com.datatorrent.stram.StreamingContainerManager.java Source code

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.datatorrent.stram;

import java.io.*;
import java.lang.management.ManagementFactory;
import java.lang.reflect.Field;
import java.net.InetSocketAddress;
import java.net.URI;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;

import javax.annotation.Nullable;

import com.datatorrent.netlet.util.DTThrowable;
import com.esotericsoftware.kryo.KryoException;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Objects;
import com.google.common.base.Predicate;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;

import net.engio.mbassy.bus.MBassador;
import net.engio.mbassy.bus.config.BusConfiguration;

import org.codehaus.jettison.json.JSONArray;
import org.codehaus.jettison.json.JSONException;
import org.codehaus.jettison.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;
import org.apache.commons.lang3.mutable.MutableInt;
import org.apache.commons.lang3.mutable.MutableLong;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CreateFlag;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileContext;
import org.apache.hadoop.fs.Options;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.yarn.api.ApplicationConstants;
import org.apache.hadoop.yarn.conf.YarnConfiguration;
import org.apache.hadoop.yarn.util.Clock;
import org.apache.hadoop.yarn.util.SystemClock;
import org.apache.hadoop.yarn.webapp.NotFoundException;

import com.datatorrent.api.*;
import com.datatorrent.api.Context.OperatorContext;
import com.datatorrent.api.Operator.InputPort;
import com.datatorrent.api.Operator.OutputPort;
import com.datatorrent.api.Stats.OperatorStats;
import com.datatorrent.api.annotation.Stateless;

import com.datatorrent.bufferserver.auth.AuthManager;
import com.datatorrent.bufferserver.util.Codec;
import com.datatorrent.common.experimental.AppData;
import com.datatorrent.common.util.AsyncFSStorageAgent;
import com.datatorrent.common.util.FSStorageAgent;
import com.datatorrent.common.util.NumberAggregate;
import com.datatorrent.common.util.Pair;
import com.datatorrent.stram.Journal.Recoverable;
import com.datatorrent.stram.StreamingContainerAgent.ContainerStartRequest;
import com.datatorrent.stram.api.*;
import com.datatorrent.stram.api.StreamingContainerUmbilicalProtocol.*;
import com.datatorrent.stram.engine.OperatorResponse;
import com.datatorrent.stram.engine.StreamingContainer;
import com.datatorrent.stram.engine.WindowGenerator;
import com.datatorrent.stram.plan.logical.LogicalOperatorStatus;
import com.datatorrent.stram.plan.logical.LogicalPlan;
import com.datatorrent.stram.plan.logical.LogicalPlan.InputPortMeta;
import com.datatorrent.stram.plan.logical.LogicalPlan.ModuleMeta;
import com.datatorrent.stram.plan.logical.LogicalPlan.OperatorMeta;
import com.datatorrent.stram.plan.logical.LogicalPlan.OutputPortMeta;
import com.datatorrent.stram.plan.logical.LogicalPlanConfiguration;
import com.datatorrent.stram.plan.logical.Operators;
import com.datatorrent.stram.plan.logical.Operators.PortContextPair;
import com.datatorrent.stram.plan.logical.requests.LogicalPlanRequest;
import com.datatorrent.stram.plan.physical.*;
import com.datatorrent.stram.plan.physical.OperatorStatus.PortStatus;
import com.datatorrent.stram.plan.physical.PTOperator.PTInput;
import com.datatorrent.stram.plan.physical.PTOperator.PTOutput;
import com.datatorrent.stram.plan.physical.PTOperator.State;
import com.datatorrent.stram.plan.physical.PhysicalPlan.PlanContext;
import com.datatorrent.stram.util.ConfigUtils;
import com.datatorrent.stram.util.FSJsonLineFile;
import com.datatorrent.stram.util.MovingAverage.MovingAverageLong;
import com.datatorrent.stram.util.SharedPubSubWebSocketClient;
import com.datatorrent.stram.util.WebServicesClient;
import com.datatorrent.stram.webapp.*;

/**
 * Tracks topology provisioning/allocation to containers<p>
 * <br>
 * The tasks include<br>
 * Provisioning operators one container at a time. Each container gets assigned the operators, streams and its context<br>
 * Monitors run time operations including heartbeat protocol and node status<br>
 * Operator recovery and restart<br>
 * <br>
 *
 * @since 0.3.2
 */
public class StreamingContainerManager implements PlanContext {
    private final static Logger LOG = LoggerFactory.getLogger(StreamingContainerManager.class);
    public final static String GATEWAY_LOGIN_URL_PATH = "/ws/v2/login";
    public final static String BUILTIN_APPDATA_URL = "builtin";
    public final static String CONTAINERS_INFO_FILENAME_FORMAT = "containers_%d.json";
    public final static String OPERATORS_INFO_FILENAME_FORMAT = "operators_%d.json";
    public final static String APP_META_FILENAME = "meta.json";
    public final static String APP_META_KEY_ATTRIBUTES = "attributes";
    public final static String APP_META_KEY_METRICS = "metrics";
    public static final String EMBEDDABLE_QUERY_NAME_SUFFIX = ".query";

    public final static long LATENCY_WARNING_THRESHOLD_MILLIS = 10 * 60 * 1000; // 10 minutes
    public final static Recoverable SET_OPERATOR_PROPERTY = new SetOperatorProperty();
    public final static Recoverable SET_PHYSICAL_OPERATOR_PROPERTY = new SetPhysicalOperatorProperty();
    public final static int METRIC_QUEUE_SIZE = 1000;

    private final FinalVars vars;
    private final PhysicalPlan plan;
    private final Clock clock;
    private SharedPubSubWebSocketClient wsClient;
    private FSStatsRecorder statsRecorder;
    private FSEventRecorder eventRecorder;
    protected final Map<String, String> containerStopRequests = new ConcurrentHashMap<String, String>();
    protected final ConcurrentLinkedQueue<ContainerStartRequest> containerStartRequests = new ConcurrentLinkedQueue<ContainerStartRequest>();
    protected boolean forcedShutdown = false;
    private final ConcurrentLinkedQueue<Runnable> eventQueue = new ConcurrentLinkedQueue<Runnable>();
    private final AtomicBoolean eventQueueProcessing = new AtomicBoolean();
    private final HashSet<PTContainer> pendingAllocation = Sets.newLinkedHashSet();
    protected String shutdownDiagnosticsMessage = "";
    private long lastResourceRequest = 0;
    private final Map<String, StreamingContainerAgent> containers = new ConcurrentHashMap<String, StreamingContainerAgent>();
    private final List<Pair<PTOperator, Long>> purgeCheckpoints = new ArrayList<Pair<PTOperator, Long>>();
    private Map<OperatorMeta, Set<OperatorMeta>> checkpointGroups;
    private final Map<Long, Set<PTOperator>> shutdownOperators = new HashMap<>();
    private CriticalPathInfo criticalPathInfo;
    private final ConcurrentMap<PTOperator, PTOperator> reportStats = Maps.newConcurrentMap();
    private final AtomicBoolean deployChangeInProgress = new AtomicBoolean();
    private int deployChangeCnt;
    private MBassador<StramEvent> eventBus; // event bus for publishing stram events
    final private Journal journal;
    private RecoveryHandler recoveryHandler;
    // window id to node id to end window stats
    private final ConcurrentSkipListMap<Long, Map<Integer, EndWindowStats>> endWindowStatsOperatorMap = new ConcurrentSkipListMap<Long, Map<Integer, EndWindowStats>>();
    private final ConcurrentMap<PTOperator, PTOperator> slowestUpstreamOp = new ConcurrentHashMap<>();
    private long committedWindowId;
    // (operator id, port name) to timestamp
    private final Map<Pair<Integer, String>, Long> operatorPortLastEndWindowTimestamps = Maps.newConcurrentMap();
    private final Map<Integer, Long> operatorLastEndWindowTimestamps = Maps.newConcurrentMap();
    private long lastStatsTimestamp = System.currentTimeMillis();
    private long currentEndWindowStatsWindowId;
    private long completeEndWindowStatsWindowId;
    private final ConcurrentHashMap<String, MovingAverageLong> rpcLatencies = new ConcurrentHashMap<String, MovingAverageLong>();
    private final AtomicLong nodeToStramRequestIds = new AtomicLong(1);
    private int allocatedMemoryMB = 0;
    private List<AppDataSource> appDataSources = null;
    private final Cache<Long, Object> commandResponse = CacheBuilder.newBuilder()
            .expireAfterWrite(1, TimeUnit.MINUTES).build();
    private long lastLatencyWarningTime;
    private transient ExecutorService poolExecutor;
    private FileContext fileContext;

    //logic operator name to a queue of logical metrics. this gets cleared periodically
    private final Map<String, Queue<Pair<Long, Map<String, Object>>>> logicalMetrics = Maps.newConcurrentMap();
    //logical operator name to latest logical metrics.
    private final Map<String, Map<String, Object>> latestLogicalMetrics = Maps.newHashMap();

    //logical operator name to latest counters. exists for backward compatibility.
    private final Map<String, Object> latestLogicalCounters = Maps.newHashMap();

    private final LinkedHashMap<String, ContainerInfo> completedContainers = new LinkedHashMap<String, ContainerInfo>() {
        private static final long serialVersionUID = 201405281500L;

        @Override
        protected boolean removeEldestEntry(Map.Entry<String, ContainerInfo> eldest) {
            long expireTime = System.currentTimeMillis() - 30 * 60 * 60;
            Iterator<Map.Entry<String, ContainerInfo>> iterator = entrySet().iterator();
            while (iterator.hasNext()) {
                Map.Entry<String, ContainerInfo> entry = iterator.next();
                if (entry.getValue().finishedTime < expireTime) {
                    iterator.remove();
                }
            }
            return false;
        }
    };

    private FSJsonLineFile containerFile;
    private FSJsonLineFile operatorFile;

    private final long startTime = System.currentTimeMillis();

    private static class EndWindowStats {
        long emitTimestamp = -1;
        HashMap<String, Long> dequeueTimestamps = new HashMap<String, Long>(); // input port name to end window dequeue time
        Object counters;
        Map<String, Object> metrics;
    }

    public static class CriticalPathInfo {
        long latency;
        final LinkedList<Integer> path;

        public CriticalPathInfo() {
            this.path = new LinkedList<>();
        }

        private CriticalPathInfo(long latency, LinkedList<Integer> path) {
            this.latency = latency;
            this.path = path;
        }

        @Override
        protected Object clone() throws CloneNotSupportedException {
            return new CriticalPathInfo(this.latency, (LinkedList<Integer>) this.path.clone());
        }
    }

    private static class SetOperatorProperty implements Recoverable {
        final private String operatorName;
        final private String propertyName;
        final private String propertyValue;

        private SetOperatorProperty() {
            this(null, null, null);
        }

        private SetOperatorProperty(String operatorName, String propertyName, String propertyValue) {
            this.operatorName = operatorName;
            this.propertyName = propertyName;
            this.propertyValue = propertyValue;
        }

        @Override
        public void read(final Object object, final Input in) throws KryoException {
            final StreamingContainerManager scm = (StreamingContainerManager) object;

            final String operatorName = in.readString();
            final String propertyName = in.readString();
            final String propertyValue = in.readString();

            final OperatorMeta logicalOperator = scm.plan.getLogicalPlan().getOperatorMeta(operatorName);
            if (logicalOperator == null) {
                throw new IllegalArgumentException("Unknown operator " + operatorName);
            }

            scm.setOperatorProperty(logicalOperator, propertyName, propertyValue);
        }

        @Override
        public void write(final Output out) throws KryoException {
            out.writeString(operatorName);
            out.writeString(propertyName);
            out.writeString(propertyValue);
        }

    }

    private static class SetPhysicalOperatorProperty implements Recoverable {
        final private int operatorId;
        final private String propertyName;
        final private String propertyValue;

        private SetPhysicalOperatorProperty() {
            this(-1, null, null);
        }

        private SetPhysicalOperatorProperty(int operatorId, String propertyName, String propertyValue) {
            this.operatorId = operatorId;
            this.propertyName = propertyName;
            this.propertyValue = propertyValue;
        }

        @Override
        public void read(final Object object, final Input in) throws KryoException {
            final StreamingContainerManager scm = (StreamingContainerManager) object;

            final int operatorId = in.readInt();
            final String propertyName = in.readString();
            final String propertyValue = in.readString();

            final PTOperator o = scm.plan.getAllOperators().get(operatorId);
            if (o == null) {
                throw new IllegalArgumentException("Unknown physical operator " + operatorId);
            }
            scm.setPhysicalOperatorProperty(o, propertyName, propertyValue);
        }

        @Override
        public void write(final Output out) throws KryoException {
            out.writeInt(operatorId);
            out.writeString(propertyName);
            out.writeString(propertyValue);
        }

    }

    public StreamingContainerManager(LogicalPlan dag, Clock clock) {
        this(dag, false, clock);
    }

    public StreamingContainerManager(LogicalPlan dag) {
        this(dag, false, new SystemClock());
    }

    public StreamingContainerManager(LogicalPlan dag, boolean enableEventRecording, Clock clock) {
        this.clock = clock;
        this.vars = new FinalVars(dag, clock.getTime());
        poolExecutor = Executors.newFixedThreadPool(4);
        // setup prior to plan creation for event recording
        if (enableEventRecording) {
            this.eventBus = new MBassador<StramEvent>(BusConfiguration.Default(1, 1, 1));
        }
        this.plan = new PhysicalPlan(dag, this);
        this.journal = new Journal(this);
        init(enableEventRecording);
    }

    private StreamingContainerManager(CheckpointState checkpointedState, boolean enableEventRecording) {
        this.vars = checkpointedState.finals;
        this.clock = new SystemClock();
        poolExecutor = Executors.newFixedThreadPool(4);
        this.plan = checkpointedState.physicalPlan;
        this.eventBus = new MBassador<StramEvent>(BusConfiguration.Default(1, 1, 1));
        this.journal = new Journal(this);
        init(enableEventRecording);
    }

    private void init(boolean enableEventRecording) {
        setupWsClient();
        setupRecording(enableEventRecording);
        setupStringCodecs();

        try {
            Path file = new Path(this.vars.appPath);
            URI uri = file.toUri();
            Configuration config = new YarnConfiguration();
            fileContext = uri.getScheme() == null ? FileContext.getFileContext(config)
                    : FileContext.getFileContext(uri, config);
            saveMetaInfo();
            String fileName = String.format(CONTAINERS_INFO_FILENAME_FORMAT,
                    plan.getLogicalPlan().getValue(LogicalPlan.APPLICATION_ATTEMPT_ID));
            this.containerFile = new FSJsonLineFile(fileContext, new Path(this.vars.appPath, fileName),
                    FsPermission.getDefault());
            this.containerFile.append(getAppMasterContainerInfo());
            fileName = String.format(OPERATORS_INFO_FILENAME_FORMAT,
                    plan.getLogicalPlan().getValue(LogicalPlan.APPLICATION_ATTEMPT_ID));
            this.operatorFile = new FSJsonLineFile(fileContext, new Path(this.vars.appPath, fileName),
                    FsPermission.getDefault());
        } catch (IOException ex) {
            throw DTThrowable.wrapIfChecked(ex);
        }
    }

    public Journal getJournal() {
        return journal;
    }

    public final ContainerInfo getAppMasterContainerInfo() {
        ContainerInfo ci = new ContainerInfo();
        ci.id = System.getenv(ApplicationConstants.Environment.CONTAINER_ID.toString());
        String nmHost = System.getenv(ApplicationConstants.Environment.NM_HOST.toString());
        String nmPort = System.getenv(ApplicationConstants.Environment.NM_PORT.toString());
        String nmHttpPort = System.getenv(ApplicationConstants.Environment.NM_HTTP_PORT.toString());
        ci.state = "ACTIVE";
        ci.jvmName = ManagementFactory.getRuntimeMXBean().getName();
        ci.numOperators = 0;
        YarnConfiguration conf = new YarnConfiguration();

        if (nmHost != null) {
            if (nmPort != null) {
                ci.host = nmHost + ":" + nmPort;
            }
            if (nmHttpPort != null) {
                String nodeHttpAddress = nmHost + ":" + nmHttpPort;
                if (allocatedMemoryMB == 0) {
                    String url = ConfigUtils.getSchemePrefix(conf) + nodeHttpAddress + "/ws/v1/node/containers/"
                            + ci.id;
                    WebServicesClient webServicesClient = new WebServicesClient();
                    try {
                        String content = webServicesClient.process(url, String.class,
                                new WebServicesClient.GetWebServicesHandler<String>());
                        JSONObject json = new JSONObject(content);
                        int totalMemoryNeededMB = json.getJSONObject("container").getInt("totalMemoryNeededMB");
                        if (totalMemoryNeededMB > 0) {
                            allocatedMemoryMB = totalMemoryNeededMB;
                        } else {
                            LOG.warn(
                                    "Could not determine the memory allocated for the streaming application master.  Node manager is reporting {} MB from {}",
                                    totalMemoryNeededMB, url);
                        }
                    } catch (Exception ex) {
                        LOG.warn("Could not determine the memory allocated for the streaming application master",
                                ex);
                    }
                }
                ci.containerLogsUrl = ConfigUtils.getSchemePrefix(conf) + nodeHttpAddress + "/node/containerlogs/"
                        + ci.id + "/" + System.getenv(ApplicationConstants.Environment.USER.toString());
                ci.rawContainerLogsUrl = ConfigUtils.getRawContainerLogsUrl(conf, nodeHttpAddress,
                        plan.getLogicalPlan().getAttributes().get(LogicalPlan.APPLICATION_ID), ci.id);
            }
        }
        ci.memoryMBAllocated = allocatedMemoryMB;
        ci.memoryMBFree = ((int) (Runtime.getRuntime().freeMemory() / (1024 * 1024)));
        ci.lastHeartbeat = -1;
        ci.startedTime = startTime;
        ci.finishedTime = -1;
        return ci;
    }

    public void updateRPCLatency(String containerId, long latency) {
        if (vars.rpcLatencyCompensationSamples > 0) {
            MovingAverageLong latencyMA = rpcLatencies.get(containerId);
            if (latencyMA == null) {
                final MovingAverageLong val = new MovingAverageLong(vars.rpcLatencyCompensationSamples);
                latencyMA = rpcLatencies.putIfAbsent(containerId, val);
                if (latencyMA == null) {
                    latencyMA = val;
                }
            }
            latencyMA.add(latency);
        }
    }

    private void setupRecording(boolean enableEventRecording) {
        if (this.vars.enableStatsRecording) {
            statsRecorder = new FSStatsRecorder();
            statsRecorder.setBasePath(this.vars.appPath + "/" + LogicalPlan.SUBDIR_STATS);
            statsRecorder.setup();
        }
        if (enableEventRecording) {
            eventRecorder = new FSEventRecorder(plan.getLogicalPlan().getValue(LogicalPlan.APPLICATION_ID));
            eventRecorder.setBasePath(this.vars.appPath + "/" + LogicalPlan.SUBDIR_EVENTS);
            eventRecorder.setWebSocketClient(wsClient);
            eventRecorder.setup();
            eventBus.subscribe(eventRecorder);
        }
    }

    private void setupStringCodecs() {
        Map<Class<?>, Class<? extends StringCodec<?>>> codecs = this.plan.getLogicalPlan().getAttributes()
                .get(Context.DAGContext.STRING_CODECS);
        StringCodecs.loadConverters(codecs);
    }

    private void setupWsClient() {
        String gatewayAddress = plan.getLogicalPlan().getValue(LogicalPlan.GATEWAY_CONNECT_ADDRESS);
        boolean gatewayUseSsl = plan.getLogicalPlan().getValue(LogicalPlan.GATEWAY_USE_SSL);
        String gatewayUserName = plan.getLogicalPlan().getValue(LogicalPlan.GATEWAY_USER_NAME);
        String gatewayPassword = plan.getLogicalPlan().getValue(LogicalPlan.GATEWAY_PASSWORD);

        if (gatewayAddress != null) {
            try {
                wsClient = new SharedPubSubWebSocketClient(
                        (gatewayUseSsl ? "wss://" : "ws://") + gatewayAddress + "/pubsub", 500);
                if (gatewayUserName != null && gatewayPassword != null) {
                    wsClient.setLoginUrl(
                            (gatewayUseSsl ? "https://" : "http://") + gatewayAddress + GATEWAY_LOGIN_URL_PATH);
                    wsClient.setUserName(gatewayUserName);
                    wsClient.setPassword(gatewayPassword);
                }
                wsClient.setup();
            } catch (Exception ex) {
                LOG.warn("Cannot establish websocket connection to {}", gatewayAddress, ex);
            }
        }
    }

    public void teardown() {
        if (eventBus != null) {
            eventBus.shutdown();
        }
        if (eventRecorder != null) {
            eventRecorder.teardown();
        }
        if (statsRecorder != null) {
            statsRecorder.teardown();
        }

        IOUtils.closeQuietly(containerFile);
        IOUtils.closeQuietly(operatorFile);
        if (poolExecutor != null) {
            poolExecutor.shutdown();
        }
    }

    public void subscribeToEvents(Object listener) {
        if (eventBus != null) {
            eventBus.subscribe(listener);
        }
    }

    public PhysicalPlan getPhysicalPlan() {
        return plan;
    }

    public long getCommittedWindowId() {
        return committedWindowId;
    }

    public boolean isGatewayConnected() {
        return wsClient != null && wsClient.isConnectionOpen();
    }

    public SharedPubSubWebSocketClient getWsClient() {
        return wsClient;
    }

    private String convertAppDataUrl(String url) {
        if (BUILTIN_APPDATA_URL.equals(url)) {
            return url;
        }
        /*else if (url != null) {      String messageProxyUrl = this.plan.getLogicalPlan().getAttributes().get(Context.DAGContext.APPLICATION_DATA_MESSAGE_PROXY_URL);
          if (messageProxyUrl != null) {
            StringBuilder convertedUrl = new StringBuilder(messageProxyUrl);
            convertedUrl.append("?url=");
            try {
              convertedUrl.append(URLEncoder.encode(url, "UTF-8"));
              return convertedUrl.toString();
            } catch (UnsupportedEncodingException ex) {
              LOG.warn("URL {} cannot be encoded", url);
            }
          }
        }
         */
        LOG.warn("App Data URL {} cannot be converted for the client.", url);
        return url;
    }

    private final Object appDataSourcesLock = new Object();

    public List<AppDataSource> getAppDataSources() {
        synchronized (appDataSourcesLock) {
            if (appDataSources == null) {
                appDataSources = new ArrayList<AppDataSource>();
                operators: for (LogicalPlan.OperatorMeta operatorMeta : plan.getLogicalPlan().getAllOperators()) {
                    Map<LogicalPlan.InputPortMeta, LogicalPlan.StreamMeta> inputStreams = operatorMeta
                            .getInputStreams();
                    Map<LogicalPlan.OutputPortMeta, LogicalPlan.StreamMeta> outputStreams = operatorMeta
                            .getOutputStreams();

                    String queryOperatorName = null;
                    String queryUrl = null;
                    String queryTopic = null;

                    boolean hasEmbeddedQuery = false;

                    //Discover embeddable query connectors
                    if (operatorMeta.getOperator() instanceof AppData.Store<?>) {
                        AppData.Store<?> store = (AppData.Store<?>) operatorMeta.getOperator();
                        AppData.EmbeddableQueryInfoProvider<?> embeddableQuery = store
                                .getEmbeddableQueryInfoProvider();

                        if (embeddableQuery != null) {
                            hasEmbeddedQuery = true;
                            queryOperatorName = operatorMeta.getName() + EMBEDDABLE_QUERY_NAME_SUFFIX;
                            queryUrl = embeddableQuery.getAppDataURL();
                            queryTopic = embeddableQuery.getTopic();
                        }
                    }

                    //Discover separate query operators
                    LOG.warn("DEBUG: looking at operator {} {}", operatorMeta.getName(),
                            Thread.currentThread().getId());
                    for (Map.Entry<LogicalPlan.InputPortMeta, LogicalPlan.StreamMeta> entry : inputStreams
                            .entrySet()) {
                        LogicalPlan.InputPortMeta portMeta = entry.getKey();
                        if (portMeta.isAppDataQueryPort()) {
                            if (queryUrl == null) {
                                OperatorMeta queryOperatorMeta = entry.getValue().getSource().getOperatorMeta();
                                if (queryOperatorMeta.getOperator() instanceof AppData.ConnectionInfoProvider) {
                                    if (!hasEmbeddedQuery) {
                                        AppData.ConnectionInfoProvider queryOperator = (AppData.ConnectionInfoProvider) queryOperatorMeta
                                                .getOperator();
                                        queryOperatorName = queryOperatorMeta.getName();
                                        queryUrl = queryOperator.getAppDataURL();
                                        queryTopic = queryOperator.getTopic();
                                    } else {
                                        LOG.warn(
                                                "An embeddable query connector and the {} query operator were discovered. "
                                                        + "The query operator will be ignored and the embeddable query connector will be used instead.",
                                                operatorMeta.getName());
                                    }
                                }
                            } else {
                                LOG.warn("Multiple query ports found in operator {}. Ignoring the App Data Source.",
                                        operatorMeta.getName());
                                continue operators;
                            }
                        }
                    }

                    for (Map.Entry<LogicalPlan.OutputPortMeta, LogicalPlan.StreamMeta> entry : outputStreams
                            .entrySet()) {
                        LogicalPlan.OutputPortMeta portMeta = entry.getKey();
                        LOG.warn("DEBUG: looking at port {} {}", portMeta.getPortName(),
                                Thread.currentThread().getId());

                        if (portMeta.isAppDataResultPort()) {
                            AppDataSource appDataSource = new AppDataSource();
                            appDataSource.setType(AppDataSource.Type.DAG);
                            appDataSource.setOperatorName(operatorMeta.getName());
                            appDataSource.setPortName(portMeta.getPortName());

                            if (queryOperatorName == null) {
                                LOG.warn(
                                        "There is no query operator for the App Data Source {}.{}. Ignoring the App Data Source.",
                                        operatorMeta.getName(), portMeta.getPortName());
                                continue;
                            }
                            appDataSource.setQueryOperatorName(queryOperatorName);
                            appDataSource.setQueryTopic(queryTopic);
                            appDataSource.setQueryUrl(convertAppDataUrl(queryUrl));
                            List<LogicalPlan.InputPortMeta> sinks = entry.getValue().getSinks();
                            if (sinks.isEmpty()) {
                                LOG.warn(
                                        "There is no result operator for the App Data Source {}.{}. Ignoring the App Data Source.",
                                        operatorMeta.getName(), portMeta.getPortName());
                                continue;
                            }
                            if (sinks.size() > 1) {
                                LOG.warn(
                                        "There are multiple result operators for the App Data Source {}.{}. Ignoring the App Data Source.",
                                        operatorMeta.getName(), portMeta.getPortName());
                                continue;
                            }
                            OperatorMeta resultOperatorMeta = sinks.get(0).getOperatorWrapper();
                            if (resultOperatorMeta.getOperator() instanceof AppData.ConnectionInfoProvider) {
                                AppData.ConnectionInfoProvider resultOperator = (AppData.ConnectionInfoProvider) resultOperatorMeta
                                        .getOperator();
                                appDataSource.setResultOperatorName(resultOperatorMeta.getName());
                                appDataSource.setResultTopic(resultOperator.getTopic());
                                appDataSource.setResultUrl(convertAppDataUrl(resultOperator.getAppDataURL()));
                                AppData.AppendQueryIdToTopic queryIdAppended = resultOperator.getClass()
                                        .getAnnotation(AppData.AppendQueryIdToTopic.class);
                                if (queryIdAppended != null && queryIdAppended.value()) {
                                    appDataSource.setResultAppendQIDTopic(true);
                                }
                            } else {
                                LOG.warn(
                                        "Result operator for the App Data Source {}.{} does not implement the right interface. Ignoring the App Data Source.",
                                        operatorMeta.getName(), portMeta.getPortName());
                                continue;
                            }
                            LOG.warn("DEBUG: Adding appDataSource {} {}", appDataSource.getName(),
                                    Thread.currentThread().getId());
                            appDataSources.add(appDataSource);
                        }
                    }
                }
            }
        }
        return appDataSources;
    }

    public Map<String, Map<String, Object>> getLatestLogicalMetrics() {
        return latestLogicalMetrics;
    }

    /**
     * Check periodically that deployed containers phone home.
     * Run from the master main loop (single threaded access).
     */
    public void monitorHeartbeat() {
        long currentTms = clock.getTime();

        // look for resource allocation timeout
        if (!pendingAllocation.isEmpty()) {
            // look for resource allocation timeout
            if (lastResourceRequest
                    + plan.getLogicalPlan().getValue(LogicalPlan.RESOURCE_ALLOCATION_TIMEOUT_MILLIS) < currentTms) {
                String msg = String.format(
                        "Shutdown due to resource allocation timeout (%s ms) waiting for %s containers",
                        currentTms - lastResourceRequest, pendingAllocation.size());
                LOG.warn(msg);
                for (PTContainer c : pendingAllocation) {
                    LOG.warn("Waiting for resource: {}m priority: {} {}", c.getRequiredMemoryMB(),
                            c.getResourceRequestPriority(), c);
                }
                shutdownAllContainers(msg);
                this.forcedShutdown = true;
            } else {
                for (PTContainer c : pendingAllocation) {
                    LOG.debug("Waiting for resource: {}m {}", c.getRequiredMemoryMB(), c);
                }
            }
        }

        // monitor currently deployed containers
        for (StreamingContainerAgent sca : containers.values()) {
            PTContainer c = sca.container;

            if (!pendingAllocation.contains(c) && c.getExternalId() != null) {
                if (sca.lastHeartbeatMillis == 0) {
                    //LOG.debug("{} {} {}", c.getExternalId(), currentTms - sca.createdMillis, this.vars.heartbeatTimeoutMillis);
                    // container allocated but process was either not launched or is not able to phone home
                    if (currentTms - sca.createdMillis > 2 * this.vars.heartbeatTimeoutMillis) {
                        LOG.info("Container {}@{} startup timeout ({} ms).", c.getExternalId(), c.host,
                                currentTms - sca.createdMillis);
                        containerStopRequests.put(c.getExternalId(), c.getExternalId());
                    }
                } else {
                    if (currentTms - sca.lastHeartbeatMillis > this.vars.heartbeatTimeoutMillis) {
                        if (!isApplicationIdle()) {
                            // request stop (kill) as process may still be hanging around (would have been detected by Yarn otherwise)
                            LOG.info("Container {}@{} heartbeat timeout ({} ms).", c.getExternalId(), c.host,
                                    currentTms - sca.lastHeartbeatMillis);
                            containerStopRequests.put(c.getExternalId(), c.getExternalId());
                        }
                    }
                }
            }
        }

        // events that may modify the plan
        processEvents();

        committedWindowId = updateCheckpoints(false);
        calculateEndWindowStats();
        if (this.vars.enableStatsRecording) {
            recordStats(currentTms);
        }
    }

    private void recordStats(long currentTms) {
        try {
            statsRecorder.recordContainers(containers, currentTms);
            statsRecorder.recordOperators(getOperatorInfoList(), currentTms);
        } catch (Exception ex) {
            LOG.warn("Exception caught when recording stats", ex);
        }
    }

    private void calculateEndWindowStats() {
        if (!endWindowStatsOperatorMap.isEmpty()) {
            Set<Integer> allCurrentOperators = plan.getAllOperators().keySet();

            if (endWindowStatsOperatorMap.size() > this.vars.maxWindowsBehindForStats) {
                LOG.warn("Some operators are behind for more than {} windows! Trimming the end window stats map",
                        this.vars.maxWindowsBehindForStats);
                while (endWindowStatsOperatorMap.size() > this.vars.maxWindowsBehindForStats) {
                    LOG.debug(
                            "Removing incomplete end window stats for window id {}. Collected operator set: {}. Complete set: {}",
                            endWindowStatsOperatorMap.firstKey(),
                            endWindowStatsOperatorMap.get(endWindowStatsOperatorMap.firstKey()).keySet(),
                            allCurrentOperators);
                    endWindowStatsOperatorMap.remove(endWindowStatsOperatorMap.firstKey());
                }
            }
            //logicalMetrics.clear();
            int numOperators = allCurrentOperators.size();
            Long windowId = endWindowStatsOperatorMap.firstKey();
            while (windowId != null) {
                Map<Integer, EndWindowStats> endWindowStatsMap = endWindowStatsOperatorMap.get(windowId);
                Set<Integer> endWindowStatsOperators = endWindowStatsMap.keySet();

                aggregateMetrics(windowId, endWindowStatsMap);
                criticalPathInfo = findCriticalPath();

                if (allCurrentOperators.containsAll(endWindowStatsOperators)) {
                    if (endWindowStatsMap.size() < numOperators) {
                        if (windowId < completeEndWindowStatsWindowId) {
                            LOG.debug("Disregarding stale end window stats for window {}", windowId);
                            endWindowStatsOperatorMap.remove(windowId);
                        } else {
                            break;
                        }
                    } else {
                        endWindowStatsOperatorMap.remove(windowId);
                        currentEndWindowStatsWindowId = windowId;
                    }
                } else {
                    // the old stats contains operators that do not exist any more
                    // this is probably right after a partition happens.
                    LOG.debug(
                            "Stats for non-existent operators detected. Disregarding end window stats for window {}",
                            windowId);
                    endWindowStatsOperatorMap.remove(windowId);
                }
                windowId = endWindowStatsOperatorMap.higherKey(windowId);
            }
        }
    }

    private void aggregateMetrics(long windowId, Map<Integer, EndWindowStats> endWindowStatsMap) {
        Collection<OperatorMeta> logicalOperators = getLogicalPlan().getAllOperators();
        //for backward compatibility
        for (OperatorMeta operatorMeta : logicalOperators) {
            @SuppressWarnings("deprecation")
            Context.CountersAggregator aggregator = operatorMeta.getValue(OperatorContext.COUNTERS_AGGREGATOR);
            if (aggregator == null) {
                continue;
            }
            Collection<PTOperator> physicalOperators = plan.getAllOperators(operatorMeta);
            List<Object> counters = Lists.newArrayList();
            for (PTOperator operator : physicalOperators) {
                EndWindowStats stats = endWindowStatsMap.get(operator.getId());
                if (stats != null && stats.counters != null) {
                    counters.add(stats.counters);
                }
            }
            if (counters.size() > 0) {
                @SuppressWarnings("deprecation")
                Object aggregate = aggregator.aggregate(counters);
                latestLogicalCounters.put(operatorMeta.getName(), aggregate);
            }
        }

        for (OperatorMeta operatorMeta : logicalOperators) {
            AutoMetric.Aggregator aggregator = operatorMeta.getMetricAggregatorMeta() != null
                    ? operatorMeta.getMetricAggregatorMeta().getAggregator()
                    : null;
            if (aggregator == null) {
                continue;
            }
            Collection<PTOperator> physicalOperators = plan.getAllOperators(operatorMeta);
            List<AutoMetric.PhysicalMetricsContext> metricPool = Lists.newArrayList();

            for (PTOperator operator : physicalOperators) {
                EndWindowStats stats = endWindowStatsMap.get(operator.getId());
                if (stats != null && stats.metrics != null) {
                    PhysicalMetricsContextImpl physicalMetrics = new PhysicalMetricsContextImpl(operator.getId(),
                            stats.metrics);
                    metricPool.add(physicalMetrics);
                }
            }
            if (metricPool.isEmpty()) {
                //nothing to aggregate
                continue;
            }
            Map<String, Object> lm = aggregator.aggregate(windowId, metricPool);

            if (lm != null && lm.size() > 0) {
                Queue<Pair<Long, Map<String, Object>>> windowMetrics = logicalMetrics.get(operatorMeta.getName());
                if (windowMetrics == null) {
                    windowMetrics = new LinkedBlockingQueue<Pair<Long, Map<String, Object>>>(METRIC_QUEUE_SIZE) {
                        private static final long serialVersionUID = 1L;

                        @Override
                        public boolean add(Pair<Long, Map<String, Object>> longMapPair) {
                            if (remainingCapacity() <= 1) {
                                remove();
                            }
                            return super.add(longMapPair);
                        }
                    };
                    logicalMetrics.put(operatorMeta.getName(), windowMetrics);
                }
                LOG.debug("Adding to logical metrics for {}", operatorMeta.getName());
                windowMetrics.add(new Pair<Long, Map<String, Object>>(windowId, lm));
                Map<String, Object> oldValue = latestLogicalMetrics.put(operatorMeta.getName(), lm);
                if (oldValue == null) {
                    try {
                        saveMetaInfo();
                    } catch (IOException ex) {
                        LOG.error(
                                "Cannot save application meta info to DFS. App data sources will not be available.",
                                ex);
                    }
                }
            }
        }
    }

    /**
     * This method is for saving meta information about this application in HDFS -- the meta information that generally
     * does not change across multiple attempts
     */
    private void saveMetaInfo() throws IOException {
        Path file = new Path(this.vars.appPath, APP_META_FILENAME + "." + System.nanoTime());
        try (FSDataOutputStream os = fileContext.create(file, EnumSet.of(CreateFlag.CREATE, CreateFlag.OVERWRITE),
                Options.CreateOpts.CreateParent.createParent())) {
            JSONObject top = new JSONObject();
            JSONObject attributes = new JSONObject();
            for (Map.Entry<Attribute<?>, Object> entry : this.plan.getLogicalPlan().getAttributes().entrySet()) {
                attributes.put(entry.getKey().getSimpleName(), entry.getValue());
            }
            JSONObject autoMetrics = new JSONObject();
            for (Map.Entry<String, Map<String, Object>> entry : latestLogicalMetrics.entrySet()) {
                autoMetrics.put(entry.getKey(), new JSONArray(entry.getValue().keySet()));
            }
            top.put(APP_META_KEY_ATTRIBUTES, attributes);
            top.put(APP_META_KEY_METRICS, autoMetrics);
            os.write(top.toString().getBytes());
        } catch (JSONException ex) {
            throw new RuntimeException(ex);
        }
        Path origPath = new Path(this.vars.appPath, APP_META_FILENAME);
        fileContext.rename(file, origPath, Options.Rename.OVERWRITE);
    }

    public Queue<Pair<Long, Map<String, Object>>> getWindowMetrics(String operatorName) {
        return logicalMetrics.get(operatorName);
    }

    private CriticalPathInfo findCriticalPath() {
        CriticalPathInfo result = null;
        List<PTOperator> leafOperators = plan.getLeafOperators();
        Map<PTOperator, CriticalPathInfo> cache = new HashMap<>();
        for (PTOperator leafOperator : leafOperators) {
            CriticalPathInfo cpi = findCriticalPathHelper(leafOperator, cache);
            if (result == null || result.latency < cpi.latency) {
                result = cpi;
            }
        }
        return result;
    }

    private CriticalPathInfo findCriticalPathHelper(PTOperator operator, Map<PTOperator, CriticalPathInfo> cache) {
        CriticalPathInfo cpi = cache.get(operator);
        if (cpi != null) {
            return cpi;
        }
        PTOperator slowestUpstreamOperator = slowestUpstreamOp.get(operator);
        if (slowestUpstreamOperator != null) {
            cpi = findCriticalPathHelper(slowestUpstreamOperator, cache);
            try {
                cpi = (CriticalPathInfo) cpi.clone();
            } catch (CloneNotSupportedException ex) {
                throw new RuntimeException();
            }
        } else {
            cpi = new CriticalPathInfo();
        }
        cpi.latency += operator.stats.getLatencyMA();
        cpi.path.addLast(operator.getId());
        cache.put(operator, cpi);
        return cpi;
    }

    public int processEvents() {
        for (PTOperator o : reportStats.keySet()) {
            List<OperatorStats> stats = o.stats.listenerStats.poll();
            if (stats != null) {
                // append into single list
                List<OperatorStats> moreStats;
                while ((moreStats = o.stats.listenerStats.poll()) != null) {
                    stats.addAll(moreStats);
                }
            }
            o.stats.lastWindowedStats = stats;
            o.stats.operatorResponses = null;
            if (!o.stats.responses.isEmpty()) {
                o.stats.operatorResponses = new ArrayList<>();
                StatsListener.OperatorResponse operatorResponse;
                while ((operatorResponse = o.stats.responses.poll()) != null) {
                    o.stats.operatorResponses.add(operatorResponse);
                }
            }
            if (o.stats.lastWindowedStats != null) {
                // call listeners only with non empty window list
                if (o.statsListeners != null) {
                    plan.onStatusUpdate(o);
                }
            }
            reportStats.remove(o);
        }

        if (!this.shutdownOperators.isEmpty()) {
            synchronized (this.shutdownOperators) {
                Iterator<Map.Entry<Long, Set<PTOperator>>> it = shutdownOperators.entrySet().iterator();
                while (it.hasNext()) {
                    Map.Entry<Long, Set<PTOperator>> windowAndOpers = it.next();
                    if (windowAndOpers.getKey().longValue() <= this.committedWindowId
                            || checkDownStreamOperators(windowAndOpers)) {
                        LOG.info("Removing inactive operators at window {} {}",
                                Codec.getStringWindowId(windowAndOpers.getKey()), windowAndOpers.getValue());
                        for (PTOperator oper : windowAndOpers.getValue()) {
                            plan.removeTerminatedPartition(oper);
                        }
                        it.remove();
                    }
                }
            }
        }

        if (!eventQueue.isEmpty()) {
            for (PTOperator oper : plan.getAllOperators().values()) {
                if (oper.getState() != PTOperator.State.ACTIVE) {
                    LOG.debug("Skipping plan updates due to inactive operator {} {}", oper, oper.getState());
                    return 0;
                }
            }
        }

        int count = 0;
        Runnable command;
        while ((command = this.eventQueue.poll()) != null) {
            eventQueueProcessing.set(true);
            try {
                command.run();
                count++;
            } catch (Exception e) {
                // TODO: handle error
                LOG.error("Failed to execute {}", command, e);
            }
            eventQueueProcessing.set(false);
        }

        if (count > 0) {
            try {
                checkpoint();
            } catch (Exception e) {
                throw new RuntimeException("Failed to checkpoint state.", e);
            }
        }

        return count;
    }

    private boolean checkDownStreamOperators(Map.Entry<Long, Set<PTOperator>> windowAndOpers) {
        // Check if all downStream operators are at higher window Ids, then operator can be removed from dag
        Set<PTOperator> downStreamOperators = getPhysicalPlan().getDependents(windowAndOpers.getValue());
        for (PTOperator oper : downStreamOperators) {
            long windowId = oper.stats.currentWindowId.get();
            if (windowId < windowAndOpers.getKey().longValue()) {
                return false;
            }
        }
        return true;
    }

    /**
     * Schedule container restart. Called by Stram after a container was terminated
     * and requires recovery (killed externally, or after heartbeat timeout). <br>
     * Recovery will resolve affected operators (within the container and
     * everything downstream with respective recovery checkpoint states).
     * Dependent operators will be undeployed and buffer server connections reset prior to
     * redeploy to recovery checkpoint.
     *
     * @param containerId
     */
    public void scheduleContainerRestart(String containerId) {
        StreamingContainerAgent cs = this.getContainerAgent(containerId);
        if (cs == null || cs.shutdownRequested) {
            // the container is no longer used / was released by us
            return;
        }

        LOG.info("Initiating recovery for {}@{}", containerId, cs.container.host);

        cs.container.setState(PTContainer.State.KILLED);
        cs.container.bufferServerAddress = null;
        cs.container.setResourceRequestPriority(-1);
        cs.container.setAllocatedMemoryMB(0);
        cs.container.setAllocatedVCores(0);

        // resolve dependencies
        UpdateCheckpointsContext ctx = new UpdateCheckpointsContext(clock, false, getCheckpointGroups());
        for (PTOperator oper : cs.container.getOperators()) {
            updateRecoveryCheckpoints(oper, ctx);
        }
        includeLocalUpstreamOperators(ctx);

        // redeploy cycle for all affected operators
        LOG.info("Affected operators {}", ctx.visited);
        deploy(Collections.<PTContainer>emptySet(), ctx.visited, Sets.newHashSet(cs.container), ctx.visited);
    }

    /**
     * Transitively add operators that are container local to the dependency set.
     * (All downstream operators were traversed during checkpoint update.)
     *
     * @param ctx
     */
    private void includeLocalUpstreamOperators(UpdateCheckpointsContext ctx) {
        Set<PTOperator> newOperators = Sets.newHashSet();
        // repeat until no more local upstream operators are found
        do {
            newOperators.clear();
            for (PTOperator oper : ctx.visited) {
                for (PTInput input : oper.getInputs()) {
                    if (input.source.source.getContainer() == oper.getContainer()) {
                        if (!ctx.visited.contains(input.source.source)) {
                            newOperators.add(input.source.source);
                        }
                    }
                }
            }
            if (!newOperators.isEmpty()) {
                for (PTOperator oper : newOperators) {
                    updateRecoveryCheckpoints(oper, ctx);
                }
            }
        } while (!newOperators.isEmpty());
    }

    public void removeContainerAgent(String containerId) {
        LOG.debug("Removing container agent {}", containerId);
        StreamingContainerAgent containerAgent = containers.remove(containerId);
        if (containerAgent != null) {
            // record operator stop for this container
            for (PTOperator oper : containerAgent.container.getOperators()) {
                StramEvent ev = new StramEvent.StopOperatorEvent(oper.getName(), oper.getId(), containerId);
                recordEventAsync(ev);
            }
            containerAgent.container.setFinishedTime(System.currentTimeMillis());
            containerAgent.container.setState(PTContainer.State.KILLED);
            completedContainers.put(containerId, containerAgent.getContainerInfo());
        }
    }

    public Collection<ContainerInfo> getCompletedContainerInfo() {
        return Collections.unmodifiableCollection(completedContainers.values());
    }

    public static class ContainerResource {
        public final String containerId;
        public final String host;
        public final int memoryMB;
        public final int vCores;
        public final int priority;
        public final String nodeHttpAddress;

        public ContainerResource(int priority, String containerId, String host, int memoryMB, int vCores,
                String nodeHttpAddress) {
            this.containerId = containerId;
            this.host = host;
            this.memoryMB = memoryMB;
            this.vCores = vCores;
            this.priority = priority;
            this.nodeHttpAddress = nodeHttpAddress;

        }

        /**
         * @return String
         */
        @Override
        public String toString() {
            return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE)
                    .append("containerId", this.containerId).append("host", this.host)
                    .append("memoryMB", this.memoryMB).toString();
        }

    }

    /**
     * Assign operators to allocated container resource.
     *
     * @param resource
     * @param bufferServerAddr
     * @return streaming container agent
     */
    public StreamingContainerAgent assignContainer(ContainerResource resource, InetSocketAddress bufferServerAddr) {
        PTContainer container = null;
        // match container waiting for resource
        for (PTContainer c : pendingAllocation) {
            if (c.getState() == PTContainer.State.NEW || c.getState() == PTContainer.State.KILLED) {
                if (c.getResourceRequestPriority() == resource.priority) {
                    container = c;
                    break;
                }
            }
        }

        if (container == null) {
            LOG.debug("No container matching allocated resource {}", resource);
            LOG.debug("Containers waiting for allocation {}", pendingAllocation);
            return null;
        }

        pendingAllocation.remove(container);
        container.setState(PTContainer.State.ALLOCATED);
        if (container.getExternalId() != null) {
            LOG.info("Removing container agent {}", container.getExternalId());
            this.containers.remove(container.getExternalId());
        }
        container.setExternalId(resource.containerId);
        container.host = resource.host;
        container.bufferServerAddress = bufferServerAddr;
        if (UserGroupInformation.isSecurityEnabled()) {
            byte[] token = AuthManager.generateToken();
            container.setBufferServerToken(token);
        }
        container.nodeHttpAddress = resource.nodeHttpAddress;
        container.setAllocatedMemoryMB(resource.memoryMB);
        container.setAllocatedVCores(resource.vCores);
        container.setStartedTime(-1);
        container.setFinishedTime(-1);
        writeJournal(container.getSetContainerState());

        StreamingContainerAgent sca = new StreamingContainerAgent(container,
                newStreamingContainerContext(container), this);
        containers.put(resource.containerId, sca);
        LOG.debug("Assigned container {} priority {}", resource.containerId, resource.priority);
        return sca;
    }

    private StreamingContainerContext newStreamingContainerContext(PTContainer container) {
        try {
            int bufferServerMemory = 0;
            Iterator<PTOperator> operatorIterator = container.getOperators().iterator();

            while (operatorIterator.hasNext()) {
                bufferServerMemory += operatorIterator.next().getBufferServerMemory();
            }
            LOG.debug("Buffer Server Memory {}", bufferServerMemory);

            // the logical plan is not to be serialized via RPC, clone attributes only
            StreamingContainerContext scc = new StreamingContainerContext(
                    plan.getLogicalPlan().getAttributes().clone(), null);
            scc.attributes.put(ContainerContext.IDENTIFIER, container.getExternalId());
            scc.attributes.put(ContainerContext.BUFFER_SERVER_MB, bufferServerMemory);
            scc.attributes.put(ContainerContext.BUFFER_SERVER_TOKEN, container.getBufferServerToken());
            scc.startWindowMillis = this.vars.windowStartMillis;
            return scc;
        } catch (CloneNotSupportedException ex) {
            throw new RuntimeException("Cannot clone DAG attributes", ex);
        }
    }

    public StreamingContainerAgent getContainerAgent(String containerId) {
        StreamingContainerAgent cs = containers.get(containerId);
        if (cs == null) {
            LOG.warn("Trying to get unknown container {}", containerId);
        }
        return cs;
    }

    public Collection<StreamingContainerAgent> getContainerAgents() {
        return this.containers.values();
    }

    private void processOperatorDeployStatus(final PTOperator oper, OperatorHeartbeat ohb,
            StreamingContainerAgent sca) {
        OperatorHeartbeat.DeployState ds = null;
        if (ohb != null) {
            ds = ohb.getState();
        }

        LOG.debug("heartbeat {} {}/{} {}", oper, oper.getState(), ds, oper.getContainer().getExternalId());

        switch (oper.getState()) {
        case ACTIVE:
            // Commented out the warning below because it's expected when the operator does something
            // quickly and goes out of commission, it will report SHUTDOWN correctly whereas this code
            // is incorrectly expecting ACTIVE to be reported.
            //LOG.warn("status out of sync {} expected {} remote {}", oper, oper.getState(), ds);
            // operator expected active, check remote status
            if (ds == null) {
                sca.deployOpers.add(oper);
            } else {
                switch (ds) {
                case SHUTDOWN:
                    // schedule operator deactivation against the windowId
                    // will be processed once window is committed and all dependent operators completed processing
                    long windowId = oper.stats.currentWindowId.get();
                    if (ohb.windowStats != null && !ohb.windowStats.isEmpty()) {
                        windowId = ohb.windowStats.get(ohb.windowStats.size() - 1).windowId;
                    }
                    LOG.debug("Operator {} deactivated at window {}", oper, windowId);
                    synchronized (this.shutdownOperators) {
                        Set<PTOperator> deactivatedOpers = this.shutdownOperators.get(windowId);
                        if (deactivatedOpers == null) {
                            this.shutdownOperators.put(windowId, deactivatedOpers = new HashSet<>());
                        }
                        deactivatedOpers.add(oper);
                    }
                    sca.undeployOpers.add(oper.getId());
                    slowestUpstreamOp.remove(oper);
                    // record operator stop event
                    recordEventAsync(new StramEvent.StopOperatorEvent(oper.getName(), oper.getId(),
                            oper.getContainer().getExternalId()));
                    break;
                case FAILED:
                    processOperatorFailure(oper);
                    sca.undeployOpers.add(oper.getId());
                    slowestUpstreamOp.remove(oper);
                    recordEventAsync(new StramEvent.StopOperatorEvent(oper.getName(), oper.getId(),
                            oper.getContainer().getExternalId()));
                    break;
                case ACTIVE:
                    break;
                }
            }
            break;
        case PENDING_UNDEPLOY:
            if (ds == null) {
                // operator no longer deployed in container
                recordEventAsync(new StramEvent.StopOperatorEvent(oper.getName(), oper.getId(),
                        oper.getContainer().getExternalId()));
                oper.setState(State.PENDING_DEPLOY);
                sca.deployOpers.add(oper);
            } else {
                // operator is currently deployed, request undeploy
                sca.undeployOpers.add(oper.getId());
                slowestUpstreamOp.remove(oper);
            }
            break;
        case PENDING_DEPLOY:
            if (ds == null) {
                // operator to be deployed
                sca.deployOpers.add(oper);
            } else {
                // operator was deployed in container
                PTContainer container = oper.getContainer();
                LOG.debug("{} marking deployed: {} remote status {}", container.getExternalId(), oper, ds);
                oper.setState(PTOperator.State.ACTIVE);
                oper.stats.lastHeartbeat = null; // reset on redeploy
                oper.stats.lastWindowIdChangeTms = clock.getTime();
                recordEventAsync(
                        new StramEvent.StartOperatorEvent(oper.getName(), oper.getId(), container.getExternalId()));
            }
            break;
        default:
            //LOG.warn("Unhandled operator state {} {} remote {}", oper, oper.getState(), ds);
            if (ds != null) {
                // operator was removed and needs to be undeployed from container
                sca.undeployOpers.add(oper.getId());
                slowestUpstreamOp.remove(oper);
                recordEventAsync(new StramEvent.StopOperatorEvent(oper.getName(), oper.getId(),
                        oper.getContainer().getExternalId()));
            }
        }
    }

    private void processOperatorFailure(PTOperator oper) {
        // count failure transitions *->FAILED, applies to initialization as well as intermittent failures
        if (oper.getState() == PTOperator.State.ACTIVE) {
            oper.setState(PTOperator.State.INACTIVE);
            oper.failureCount++;
            oper.getOperatorMeta().getStatus().failureCount++;
            LOG.warn("Operator failure: {} count: {}", oper, oper.failureCount);
            Integer maxAttempts = oper.getOperatorMeta().getValue(OperatorContext.RECOVERY_ATTEMPTS);
            if (maxAttempts == null || oper.failureCount <= maxAttempts) {
                // restart entire container in attempt to recover operator
                // in the future a more sophisticated recovery strategy could
                // involve initial redeploy attempt(s) of affected operator in
                // existing container or sandbox container for just the operator
                LOG.error("Initiating container restart after operator failure {}", oper);
                containerStopRequests.put(oper.getContainer().getExternalId(), oper.getContainer().getExternalId());
            } else {
                String msg = String.format("Shutdown after reaching failure threshold for %s", oper);
                LOG.warn(msg);
                shutdownAllContainers(msg);
                forcedShutdown = true;
            }
        } else {
            // should not get here
            LOG.warn("Failed operator {} {} {} to be undeployed by container", oper, oper.getState());
        }
    }

    /**
     * process the heartbeat from each container.
     * called by the RPC thread for each container. (i.e. called by multiple threads)
     *
     * @param heartbeat
     * @return heartbeat response
     */
    @SuppressWarnings("StatementWithEmptyBody")
    public ContainerHeartbeatResponse processHeartbeat(ContainerHeartbeat heartbeat) {
        long currentTimeMillis = clock.getTime();

        final StreamingContainerAgent sca = this.containers.get(heartbeat.getContainerId());
        if (sca == null || sca.container.getState() == PTContainer.State.KILLED) {
            // could be orphaned container that was replaced and needs to terminate
            LOG.error("Unknown container {}", heartbeat.getContainerId());
            ContainerHeartbeatResponse response = new ContainerHeartbeatResponse();
            response.shutdown = true;
            return response;
        }

        //LOG.debug("{} {} {}", new Object[]{sca.container.containerId, sca.container.bufferServerAddress, sca.container.getState()});
        if (sca.container.getState() == PTContainer.State.ALLOCATED) {
            // capture dynamically assigned address from container
            if (sca.container.bufferServerAddress == null && heartbeat.bufferServerHost != null) {
                sca.container.bufferServerAddress = InetSocketAddress.createUnresolved(heartbeat.bufferServerHost,
                        heartbeat.bufferServerPort);
                LOG.info("Container {} buffer server: {}", sca.container.getExternalId(),
                        sca.container.bufferServerAddress);
            }
            final long containerStartTime = System.currentTimeMillis();
            sca.container.setState(PTContainer.State.ACTIVE);
            sca.container.setStartedTime(containerStartTime);
            sca.container.setFinishedTime(-1);
            sca.jvmName = heartbeat.jvmName;
            poolExecutor.submit(new Runnable() {
                @Override
                public void run() {
                    try {
                        containerFile.append(sca.getContainerInfo());
                    } catch (IOException ex) {
                        LOG.warn("Cannot write to container file");
                    }
                    for (PTOperator ptOp : sca.container.getOperators()) {
                        try {
                            JSONObject operatorInfo = new JSONObject();
                            operatorInfo.put("name", ptOp.getName());
                            operatorInfo.put("id", ptOp.getId());
                            operatorInfo.put("container", sca.container.getExternalId());
                            operatorInfo.put("startTime", containerStartTime);
                            operatorFile.append(operatorInfo);
                        } catch (IOException | JSONException ex) {
                            LOG.warn("Cannot write to operator file: ", ex);
                        }
                    }
                }
            });
        }

        if (heartbeat.restartRequested) {
            LOG.error("Container {} restart request", sca.container.getExternalId());
            containerStopRequests.put(sca.container.getExternalId(), sca.container.getExternalId());
        }

        sca.memoryMBFree = heartbeat.memoryMBFree;
        sca.gcCollectionCount = heartbeat.gcCollectionCount;
        sca.gcCollectionTime = heartbeat.gcCollectionTime;

        sca.undeployOpers.clear();
        sca.deployOpers.clear();
        if (!this.deployChangeInProgress.get()) {
            sca.deployCnt = this.deployChangeCnt;
        }
        Set<Integer> reportedOperators = Sets.newHashSetWithExpectedSize(sca.container.getOperators().size());

        for (OperatorHeartbeat shb : heartbeat.getContainerStats().operators) {

            long maxEndWindowTimestamp = 0;

            reportedOperators.add(shb.nodeId);
            PTOperator oper = this.plan.getAllOperators().get(shb.getNodeId());

            if (oper == null) {
                LOG.info("Heartbeat for unknown operator {} (container {})", shb.getNodeId(),
                        heartbeat.getContainerId());
                sca.undeployOpers.add(shb.nodeId);
                continue;
            }

            if (shb.requestResponse != null) {
                for (StatsListener.OperatorResponse obj : shb.requestResponse) {
                    if (obj instanceof OperatorResponse) { // This is to identify platform requests
                        commandResponse.put((Long) obj.getResponseId(), obj.getResponse());
                        LOG.debug(" Got back the response {} for the request {}", obj, obj.getResponseId());
                    } else { // This is to identify user requests
                        oper.stats.responses.add(obj);
                    }
                }
            }

            //LOG.debug("heartbeat {} {}/{} {}", oper, oper.getState(), shb.getState(), oper.getContainer().getExternalId());
            if (!(oper.getState() == PTOperator.State.ACTIVE
                    && shb.getState() == OperatorHeartbeat.DeployState.ACTIVE)) {
                // deploy state may require synchronization
                processOperatorDeployStatus(oper, shb, sca);
            }

            oper.stats.lastHeartbeat = shb;
            List<ContainerStats.OperatorStats> statsList = shb.getOperatorStatsContainer();

            if (!statsList.isEmpty()) {
                long tuplesProcessed = 0;
                long tuplesEmitted = 0;
                long totalCpuTimeUsed = 0;
                int statCount = 0;
                long maxDequeueTimestamp = -1;
                oper.stats.recordingId = null;

                final OperatorStatus status = oper.stats;
                status.statsRevs.checkout();

                for (Map.Entry<String, PortStatus> entry : status.inputPortStatusList.entrySet()) {
                    entry.getValue().recordingId = null;
                }
                for (Map.Entry<String, PortStatus> entry : status.outputPortStatusList.entrySet()) {
                    entry.getValue().recordingId = null;
                }
                for (ContainerStats.OperatorStats stats : statsList) {
                    if (stats == null) {
                        LOG.warn("Operator {} statistics list contains null element", shb.getNodeId());
                        continue;
                    }

                    /* report checkpoint-ed WindowId status of the operator */
                    if (stats.checkpoint instanceof Checkpoint) {
                        if (oper.getRecentCheckpoint() == null
                                || oper.getRecentCheckpoint().windowId < stats.checkpoint.getWindowId()) {
                            addCheckpoint(oper, (Checkpoint) stats.checkpoint);
                            if (stats.checkpointStats != null) {
                                status.checkpointStats = stats.checkpointStats;
                                status.checkpointTimeMA.add(stats.checkpointStats.checkpointTime);
                            }
                            oper.failureCount = 0;
                        }
                    }

                    oper.stats.recordingId = stats.recordingId;

                    /* report all the other stuff */

                    // calculate the stats related to end window
                    EndWindowStats endWindowStats = new EndWindowStats(); // end window stats for a particular window id for a particular node
                    Collection<ContainerStats.OperatorStats.PortStats> ports = stats.inputPorts;
                    if (ports != null) {
                        Set<String> currentInputPortSet = Sets.newHashSetWithExpectedSize(ports.size());
                        for (ContainerStats.OperatorStats.PortStats s : ports) {
                            currentInputPortSet.add(s.id);
                            PortStatus ps = status.inputPortStatusList.get(s.id);
                            if (ps == null) {
                                ps = status.new PortStatus();
                                ps.portName = s.id;
                                status.inputPortStatusList.put(s.id, ps);
                            }
                            ps.totalTuples += s.tupleCount;
                            ps.recordingId = s.recordingId;

                            tuplesProcessed += s.tupleCount;
                            endWindowStats.dequeueTimestamps.put(s.id, s.endWindowTimestamp);

                            Pair<Integer, String> operatorPortName = new Pair<>(oper.getId(), s.id);
                            Long lastEndWindowTimestamp = operatorPortLastEndWindowTimestamps.get(operatorPortName);
                            if (lastEndWindowTimestamp == null) {
                                lastEndWindowTimestamp = lastStatsTimestamp;
                            }
                            long portElapsedMillis = Math.max(s.endWindowTimestamp - lastEndWindowTimestamp, 0);
                            //LOG.debug("=== PROCESSED TUPLE COUNT for {}: {}, {}, {}, {}", operatorPortName, s.tupleCount, portElapsedMillis, operatorPortLastEndWindowTimestamps.get(operatorPortName), lastStatsTimestamp);
                            ps.tuplesPMSMA.add(s.tupleCount, portElapsedMillis);
                            ps.bufferServerBytesPMSMA.add(s.bufferServerBytes, portElapsedMillis);
                            ps.queueSizeMA.add(s.queueSize);

                            operatorPortLastEndWindowTimestamps.put(operatorPortName, s.endWindowTimestamp);
                            if (maxEndWindowTimestamp < s.endWindowTimestamp) {
                                maxEndWindowTimestamp = s.endWindowTimestamp;
                            }
                            if (s.endWindowTimestamp > maxDequeueTimestamp) {
                                maxDequeueTimestamp = s.endWindowTimestamp;
                            }
                        }
                        // need to remove dead ports, for unifiers
                        Iterator<Map.Entry<String, PortStatus>> it = status.inputPortStatusList.entrySet()
                                .iterator();
                        while (it.hasNext()) {
                            Map.Entry<String, PortStatus> entry = it.next();
                            if (!currentInputPortSet.contains(entry.getKey())) {
                                it.remove();
                            }
                        }
                    }

                    ports = stats.outputPorts;
                    if (ports != null) {
                        Set<String> currentOutputPortSet = Sets.newHashSetWithExpectedSize(ports.size());
                        for (ContainerStats.OperatorStats.PortStats s : ports) {
                            currentOutputPortSet.add(s.id);
                            PortStatus ps = status.outputPortStatusList.get(s.id);
                            if (ps == null) {
                                ps = status.new PortStatus();
                                ps.portName = s.id;
                                status.outputPortStatusList.put(s.id, ps);
                            }
                            ps.totalTuples += s.tupleCount;
                            ps.recordingId = s.recordingId;

                            tuplesEmitted += s.tupleCount;
                            Pair<Integer, String> operatorPortName = new Pair<>(oper.getId(), s.id);
                            Long lastEndWindowTimestamp = operatorPortLastEndWindowTimestamps.get(operatorPortName);
                            if (lastEndWindowTimestamp == null) {
                                lastEndWindowTimestamp = lastStatsTimestamp;
                            }
                            long portElapsedMillis = Math.max(s.endWindowTimestamp - lastEndWindowTimestamp, 0);
                            //LOG.debug("=== EMITTED TUPLE COUNT for {}: {}, {}, {}, {}", operatorPortName, s.tupleCount, portElapsedMillis, operatorPortLastEndWindowTimestamps.get(operatorPortName), lastStatsTimestamp);
                            ps.tuplesPMSMA.add(s.tupleCount, portElapsedMillis);
                            ps.bufferServerBytesPMSMA.add(s.bufferServerBytes, portElapsedMillis);

                            operatorPortLastEndWindowTimestamps.put(operatorPortName, s.endWindowTimestamp);
                            if (maxEndWindowTimestamp < s.endWindowTimestamp) {
                                maxEndWindowTimestamp = s.endWindowTimestamp;
                            }
                        }
                        if (ports.size() > 0) {
                            endWindowStats.emitTimestamp = ports.iterator().next().endWindowTimestamp;
                        }
                        // need to remove dead ports, for unifiers
                        Iterator<Map.Entry<String, PortStatus>> it = status.outputPortStatusList.entrySet()
                                .iterator();
                        while (it.hasNext()) {
                            Map.Entry<String, PortStatus> entry = it.next();
                            if (!currentOutputPortSet.contains(entry.getKey())) {
                                it.remove();
                            }
                        }
                    }

                    // for output operator, just take the maximum dequeue time for emit timestamp.
                    // (we don't know the latency for output operators because they don't emit tuples)
                    if (endWindowStats.emitTimestamp < 0) {
                        endWindowStats.emitTimestamp = maxDequeueTimestamp;
                    }

                    if (status.currentWindowId.get() != stats.windowId) {
                        status.lastWindowIdChangeTms = currentTimeMillis;
                        status.currentWindowId.set(stats.windowId);
                    }
                    totalCpuTimeUsed += stats.cpuTimeUsed;
                    statCount++;

                    if (oper.getOperatorMeta().getValue(OperatorContext.COUNTERS_AGGREGATOR) != null) {
                        endWindowStats.counters = stats.counters;
                    }
                    if (oper.getOperatorMeta().getMetricAggregatorMeta() != null
                            && oper.getOperatorMeta().getMetricAggregatorMeta().getAggregator() != null) {
                        endWindowStats.metrics = stats.metrics;
                    }

                    if (stats.windowId > currentEndWindowStatsWindowId) {
                        Map<Integer, EndWindowStats> endWindowStatsMap = endWindowStatsOperatorMap
                                .get(stats.windowId);
                        if (endWindowStatsMap == null) {
                            endWindowStatsMap = new ConcurrentSkipListMap<Integer, EndWindowStats>();
                            Map<Integer, EndWindowStats> endWindowStatsMapPrevious = endWindowStatsOperatorMap
                                    .putIfAbsent(stats.windowId, endWindowStatsMap);
                            if (endWindowStatsMapPrevious != null) {
                                endWindowStatsMap = endWindowStatsMapPrevious;
                            }
                        }
                        endWindowStatsMap.put(shb.getNodeId(), endWindowStats);

                        if (!oper.getInputs().isEmpty()) {
                            long latency = Long.MAX_VALUE;
                            long adjustedEndWindowEmitTimestamp = endWindowStats.emitTimestamp;
                            MovingAverageLong rpcLatency = rpcLatencies.get(oper.getContainer().getExternalId());
                            if (rpcLatency != null) {
                                adjustedEndWindowEmitTimestamp += rpcLatency.getAvg();
                            }
                            PTOperator slowestUpstream = null;
                            for (PTInput input : oper.getInputs()) {
                                PTOperator upstreamOp = input.source.source;
                                if (upstreamOp.getOperatorMeta().getOperator() instanceof Operator.DelayOperator) {
                                    continue;
                                }
                                EndWindowStats ews = endWindowStatsMap.get(upstreamOp.getId());
                                long portLatency;
                                if (ews == null) {
                                    // This is when the operator is likely to be behind too many windows. We need to give an estimate for
                                    // latency at this point, by looking at the number of windows behind
                                    int widthMillis = plan.getLogicalPlan()
                                            .getValue(LogicalPlan.STREAMING_WINDOW_SIZE_MILLIS);
                                    portLatency = (upstreamOp.stats.currentWindowId.get()
                                            - oper.stats.currentWindowId.get()) * widthMillis;
                                } else {
                                    MovingAverageLong upstreamRPCLatency = rpcLatencies
                                            .get(upstreamOp.getContainer().getExternalId());
                                    portLatency = adjustedEndWindowEmitTimestamp - ews.emitTimestamp;
                                    if (upstreamRPCLatency != null) {
                                        portLatency -= upstreamRPCLatency.getAvg();
                                    }
                                }
                                if (portLatency < 0) {
                                    portLatency = 0;
                                }
                                if (latency > portLatency) {
                                    latency = portLatency;
                                    slowestUpstream = upstreamOp;
                                }
                            }
                            status.latencyMA.add(latency);
                            slowestUpstreamOp.put(oper, slowestUpstream);
                        }

                        Set<Integer> allCurrentOperators = plan.getAllOperators().keySet();
                        int numOperators = plan.getAllOperators().size();
                        if (allCurrentOperators.containsAll(endWindowStatsMap.keySet())
                                && endWindowStatsMap.size() == numOperators) {
                            completeEndWindowStatsWindowId = stats.windowId;
                        }
                    }
                }

                status.totalTuplesProcessed.add(tuplesProcessed);
                status.totalTuplesEmitted.add(tuplesEmitted);
                OperatorMeta logicalOperator = oper.getOperatorMeta();
                LogicalOperatorStatus logicalStatus = logicalOperator.getStatus();
                if (!oper.isUnifier()) {
                    logicalStatus.totalTuplesProcessed += tuplesProcessed;
                    logicalStatus.totalTuplesEmitted += tuplesEmitted;
                }
                long lastMaxEndWindowTimestamp = operatorLastEndWindowTimestamps.containsKey(oper.getId())
                        ? operatorLastEndWindowTimestamps.get(oper.getId())
                        : lastStatsTimestamp;
                if (maxEndWindowTimestamp >= lastMaxEndWindowTimestamp) {
                    double tuplesProcessedPMSMA = 0.0;
                    double tuplesEmittedPMSMA = 0.0;
                    if (statCount != 0) {
                        //LOG.debug("CPU for {}: {} / {} - {}", oper.getId(), totalCpuTimeUsed, maxEndWindowTimestamp, lastMaxEndWindowTimestamp);
                        status.cpuNanosPMSMA.add(totalCpuTimeUsed,
                                maxEndWindowTimestamp - lastMaxEndWindowTimestamp);
                    }

                    for (PortStatus ps : status.inputPortStatusList.values()) {
                        tuplesProcessedPMSMA += ps.tuplesPMSMA.getAvg();
                    }
                    for (PortStatus ps : status.outputPortStatusList.values()) {
                        tuplesEmittedPMSMA += ps.tuplesPMSMA.getAvg();
                    }
                    status.tuplesProcessedPSMA.set(Math.round(tuplesProcessedPMSMA * 1000));
                    status.tuplesEmittedPSMA.set(Math.round(tuplesEmittedPMSMA * 1000));
                } else {
                    //LOG.warn("This timestamp for {} is lower than the previous!! {} < {}", oper.getId(), maxEndWindowTimestamp, lastMaxEndWindowTimestamp);
                }
                operatorLastEndWindowTimestamps.put(oper.getId(), maxEndWindowTimestamp);
                status.listenerStats.add(statsList);
                this.reportStats.put(oper, oper);

                status.statsRevs.commit();
            }
            if (lastStatsTimestamp < maxEndWindowTimestamp) {
                lastStatsTimestamp = maxEndWindowTimestamp;
            }
        }

        sca.lastHeartbeatMillis = currentTimeMillis;

        for (PTOperator oper : sca.container.getOperators()) {
            if (!reportedOperators.contains(oper.getId())) {
                processOperatorDeployStatus(oper, null, sca);
            }
        }

        ContainerHeartbeatResponse rsp = getHeartbeatResponse(sca);

        if (heartbeat.getContainerStats().operators.isEmpty() && isApplicationIdle()) {
            LOG.info("requesting idle shutdown for container {}", heartbeat.getContainerId());
            rsp.shutdown = true;
        } else {
            if (sca.shutdownRequested) {
                LOG.info("requesting shutdown for container {}", heartbeat.getContainerId());
                rsp.shutdown = true;
            }
        }

        List<StramToNodeRequest> requests = rsp.nodeRequests != null ? rsp.nodeRequests
                : new ArrayList<StramToNodeRequest>();
        ConcurrentLinkedQueue<StramToNodeRequest> operatorRequests = sca.getOperatorRequests();
        while (true) {
            StramToNodeRequest r = operatorRequests.poll();
            if (r == null) {
                break;
            }
            requests.add(r);
        }
        rsp.nodeRequests = requests;
        rsp.committedWindowId = committedWindowId;
        return rsp;
    }

    private ContainerHeartbeatResponse getHeartbeatResponse(StreamingContainerAgent sca) {
        ContainerHeartbeatResponse rsp = new ContainerHeartbeatResponse();
        if (this.deployChangeInProgress.get() || sca.deployCnt != this.deployChangeCnt) {
            LOG.debug("{} deferred requests due to concurrent plan change.", sca.container.toIdStateString());
            rsp.hasPendingRequests = true;
            return rsp;
        }

        if (!sca.undeployOpers.isEmpty()) {
            rsp.undeployRequest = Lists.newArrayList(sca.undeployOpers);
            rsp.hasPendingRequests = (!sca.deployOpers.isEmpty());
            return rsp;
        }

        Set<PTOperator> deployOperators = sca.deployOpers;
        if (!deployOperators.isEmpty()) {
            // deploy once all containers are running and no undeploy operations are pending.
            for (PTContainer c : getPhysicalPlan().getContainers()) {
                if (c.getState() != PTContainer.State.ACTIVE) {
                    LOG.debug("{} waiting for container activation {}", sca.container.toIdStateString(),
                            c.toIdStateString());
                    rsp.hasPendingRequests = true;
                    return rsp;
                }
                for (PTOperator oper : c.getOperators()) {
                    if (oper.getState() == PTOperator.State.PENDING_UNDEPLOY) {
                        LOG.debug("{} waiting for undeploy {} {}", sca.container.toIdStateString(),
                                c.toIdStateString(), oper);
                        rsp.hasPendingRequests = true;
                        return rsp;
                    }
                }
            }

            LOG.debug("{} deployable operators: {}", sca.container.toIdStateString(), deployOperators);
            List<OperatorDeployInfo> deployList = sca.getDeployInfoList(deployOperators);
            if (deployList != null && !deployList.isEmpty()) {
                rsp.deployRequest = deployList;
                rsp.nodeRequests = Lists.newArrayList();
                for (PTOperator o : deployOperators) {
                    rsp.nodeRequests.addAll(o.deployRequests);
                }
            }
            rsp.hasPendingRequests = false;
            return rsp;
        }
        return rsp;
    }

    private boolean isApplicationIdle() {
        if (eventQueueProcessing.get()) {
            return false;
        }
        for (StreamingContainerAgent sca : this.containers.values()) {
            if (sca.hasPendingWork()) {
                // container may have no active operators but deploy request pending
                return false;
            }
            for (PTOperator oper : sca.container.getOperators()) {
                if (!oper.stats.isIdle()) {
                    return false;
                }
            }
        }
        return true;
    }

    @SuppressWarnings("StatementWithEmptyBody")
    void addCheckpoint(PTOperator node, Checkpoint checkpoint) {
        synchronized (node.checkpoints) {
            if (!node.checkpoints.isEmpty()) {
                Checkpoint lastCheckpoint = node.checkpoints.getLast();
                // skip unless checkpoint moves
                if (lastCheckpoint.windowId != checkpoint.windowId) {
                    if (lastCheckpoint.windowId > checkpoint.windowId) {
                        // list needs to have max windowId last
                        LOG.warn("Out of sequence checkpoint {} last {} (operator {})", checkpoint, lastCheckpoint,
                                node);
                        ListIterator<Checkpoint> li = node.checkpoints.listIterator();
                        while (li.hasNext() && li.next().windowId < checkpoint.windowId) {
                            //continue;
                        }
                        if (li.previous().windowId != checkpoint.windowId) {
                            li.add(checkpoint);
                        }
                    } else {
                        node.checkpoints.add(checkpoint);
                    }
                }
            } else {
                node.checkpoints.add(checkpoint);
            }
        }
    }

    public static class UpdateCheckpointsContext {
        public final MutableLong committedWindowId = new MutableLong(Long.MAX_VALUE);
        public final Set<PTOperator> visited = new LinkedHashSet<PTOperator>();
        public final Set<PTOperator> blocked = new LinkedHashSet<PTOperator>();
        public final long currentTms;
        public final boolean recovery;
        public final Map<OperatorMeta, Set<OperatorMeta>> checkpointGroups;

        public UpdateCheckpointsContext(Clock clock) {
            this(clock, false, Collections.<OperatorMeta, Set<OperatorMeta>>emptyMap());
        }

        public UpdateCheckpointsContext(Clock clock, boolean recovery,
                Map<OperatorMeta, Set<OperatorMeta>> checkpointGroups) {
            this.currentTms = clock.getTime();
            this.recovery = recovery;
            this.checkpointGroups = checkpointGroups;
        }
    }

    /**
     * Compute checkpoints required for a given operator instance to be recovered.
     * This is done by looking at checkpoints available for downstream dependencies first,
     * and then selecting the most recent available checkpoint that is smaller than downstream.
     *
     * @param operator Operator instance for which to find recovery checkpoint
     * @param ctx      Context into which to collect traversal info
     */
    public void updateRecoveryCheckpoints(PTOperator operator, UpdateCheckpointsContext ctx) {
        if (operator.getRecoveryCheckpoint().windowId < ctx.committedWindowId.longValue()) {
            ctx.committedWindowId.setValue(operator.getRecoveryCheckpoint().windowId);
        }

        if (operator.getState() == PTOperator.State.ACTIVE && (ctx.currentTms
                - operator.stats.lastWindowIdChangeTms) > operator.stats.windowProcessingTimeoutMillis) {
            // if the checkpoint is ahead, then it is not blocked but waiting for activation (state-less recovery, at-most-once)
            if (ctx.committedWindowId.longValue() >= operator.getRecoveryCheckpoint().windowId) {
                LOG.debug("Marking operator {} blocked committed window {}, recovery window {}", operator,
                        Codec.getStringWindowId(ctx.committedWindowId.longValue()),
                        Codec.getStringWindowId(operator.getRecoveryCheckpoint().windowId));
                ctx.blocked.add(operator);
            }
        }

        // the most recent checkpoint eligible for recovery based on downstream state
        Checkpoint maxCheckpoint = Checkpoint.INITIAL_CHECKPOINT;

        Set<OperatorMeta> checkpointGroup = ctx.checkpointGroups.get(operator.getOperatorMeta());
        if (checkpointGroup == null) {
            checkpointGroup = Collections.singleton(operator.getOperatorMeta());
        }
        // find intersection of checkpoints that group can collectively move to
        TreeSet<Checkpoint> commonCheckpoints = new TreeSet<>(new Checkpoint.CheckpointComparator());
        synchronized (operator.checkpoints) {
            commonCheckpoints.addAll(operator.checkpoints);
        }
        Set<PTOperator> groupOpers = new HashSet<>(checkpointGroup.size());
        boolean pendingDeploy = operator.getState() == PTOperator.State.PENDING_DEPLOY;
        if (checkpointGroup.size() > 1) {
            for (OperatorMeta om : checkpointGroup) {
                Collection<PTOperator> operators = plan.getAllOperators(om);
                for (PTOperator groupOper : operators) {
                    synchronized (groupOper.checkpoints) {
                        commonCheckpoints.retainAll(groupOper.checkpoints);
                    }
                    // visit all downstream operators of the group
                    ctx.visited.add(groupOper);
                    groupOpers.add(groupOper);
                    pendingDeploy |= operator.getState() == PTOperator.State.PENDING_DEPLOY;
                }
            }
            // highest common checkpoint
            if (!commonCheckpoints.isEmpty()) {
                maxCheckpoint = commonCheckpoints.last();
            }
        } else {
            // without logical grouping, treat partitions as independent
            // this is especially important for parallel partitioning
            ctx.visited.add(operator);
            groupOpers.add(operator);
            maxCheckpoint = operator.getRecentCheckpoint();
            if (ctx.recovery && maxCheckpoint.windowId == Stateless.WINDOW_ID && operator.isOperatorStateLess()) {
                long currentWindowId = WindowGenerator.getWindowId(ctx.currentTms, this.vars.windowStartMillis,
                        this.getLogicalPlan().getValue(LogicalPlan.STREAMING_WINDOW_SIZE_MILLIS));
                maxCheckpoint = new Checkpoint(currentWindowId, 0, 0);
            }
        }

        // DFS downstream operators
        for (PTOperator groupOper : groupOpers) {
            for (PTOperator.PTOutput out : groupOper.getOutputs()) {
                for (PTOperator.PTInput sink : out.sinks) {
                    PTOperator sinkOperator = sink.target;
                    if (groupOpers.contains(sinkOperator)) {
                        continue; // downstream operator within group
                    }
                    if (!ctx.visited.contains(sinkOperator)) {
                        // downstream traversal
                        updateRecoveryCheckpoints(sinkOperator, ctx);
                    }
                    // recovery window id cannot move backwards
                    // when dynamically adding new operators
                    if (sinkOperator.getRecoveryCheckpoint().windowId >= operator
                            .getRecoveryCheckpoint().windowId) {
                        maxCheckpoint = Checkpoint.min(maxCheckpoint, sinkOperator.getRecoveryCheckpoint());
                    }

                    if (ctx.blocked.contains(sinkOperator)) {
                        if (sinkOperator.stats.getCurrentWindowId() == operator.stats.getCurrentWindowId()) {
                            // downstream operator is blocked by this operator
                            ctx.blocked.remove(sinkOperator);
                        }
                    }
                }
            }
        }

        // find the common checkpoint that is <= downstream recovery checkpoint
        if (!commonCheckpoints.contains(maxCheckpoint)) {
            if (!commonCheckpoints.isEmpty()) {
                maxCheckpoint = Objects.firstNonNull(commonCheckpoints.floor(maxCheckpoint), maxCheckpoint);
            }
        }

        for (PTOperator groupOper : groupOpers) {
            // checkpoint frozen during deployment
            if (!pendingDeploy || ctx.recovery) {
                // remove previous checkpoints
                Checkpoint c1 = Checkpoint.INITIAL_CHECKPOINT;
                LinkedList<Checkpoint> checkpoints = groupOper.checkpoints;
                synchronized (checkpoints) {
                    if (!checkpoints.isEmpty() && (checkpoints.getFirst()).windowId <= maxCheckpoint.windowId) {
                        c1 = checkpoints.getFirst();
                        Checkpoint c2;
                        while (checkpoints.size() > 1
                                && ((c2 = checkpoints.get(1)).windowId) <= maxCheckpoint.windowId) {
                            checkpoints.removeFirst();
                            //LOG.debug("Checkpoint to delete: operator={} windowId={}", operator.getName(), c1);
                            this.purgeCheckpoints.add(new Pair<PTOperator, Long>(groupOper, c1.windowId));
                            c1 = c2;
                        }
                    } else {
                        if (ctx.recovery && checkpoints.isEmpty() && groupOper.isOperatorStateLess()) {
                            LOG.debug("Adding checkpoint for stateless operator {} {}", groupOper,
                                    Codec.getStringWindowId(maxCheckpoint.windowId));
                            c1 = groupOper.addCheckpoint(maxCheckpoint.windowId, this.vars.windowStartMillis);
                        }
                    }
                }
                //LOG.debug("Operator {} checkpoints: commit {} recent {}", new Object[] {operator.getName(), c1, operator.checkpoints});
                groupOper.setRecoveryCheckpoint(c1);
            } else {
                LOG.debug("Skipping checkpoint update {} during {}", groupOper, groupOper.getState());
            }
        }

    }

    public long windowIdToMillis(long windowId) {
        int widthMillis = plan.getLogicalPlan().getValue(LogicalPlan.STREAMING_WINDOW_SIZE_MILLIS);
        return WindowGenerator.getWindowMillis(windowId, this.vars.windowStartMillis, widthMillis);
    }

    public long getWindowStartMillis() {
        return this.vars.windowStartMillis;
    }

    private Map<OperatorMeta, Set<OperatorMeta>> getCheckpointGroups() {
        if (this.checkpointGroups == null) {
            this.checkpointGroups = new HashMap<>();
            LogicalPlan dag = this.plan.getLogicalPlan();
            dag.resetNIndex();
            LogicalPlan.ValidationContext vc = new LogicalPlan.ValidationContext();
            for (OperatorMeta om : dag.getRootOperators()) {
                this.plan.getLogicalPlan().findStronglyConnected(om, vc);
            }
            for (Set<OperatorMeta> checkpointGroup : vc.stronglyConnected) {
                for (OperatorMeta om : checkpointGroup) {
                    this.checkpointGroups.put(om, checkpointGroup);
                }
            }
        }
        return checkpointGroups;
    }

    /**
     * Visit all operators to update current checkpoint based on updated downstream state.
     * Purge older checkpoints that are no longer needed.
     */
    private long updateCheckpoints(boolean recovery) {
        UpdateCheckpointsContext ctx = new UpdateCheckpointsContext(clock, recovery, getCheckpointGroups());
        for (OperatorMeta logicalOperator : plan.getLogicalPlan().getRootOperators()) {
            //LOG.debug("Updating checkpoints for operator {}", logicalOperator.getName());
            List<PTOperator> operators = plan.getOperators(logicalOperator);
            if (operators != null) {
                for (PTOperator operator : operators) {
                    updateRecoveryCheckpoints(operator, ctx);
                }
            }
        }
        purgeCheckpoints();

        for (PTOperator oper : ctx.blocked) {
            String containerId = oper.getContainer().getExternalId();
            if (containerId != null) {
                LOG.info("Blocked operator {} container {} time {}ms", oper, oper.getContainer().toIdStateString(),
                        ctx.currentTms - oper.stats.lastWindowIdChangeTms);
                this.containerStopRequests.put(containerId, containerId);
            }
        }
        return ctx.committedWindowId.longValue();
    }

    private BufferServerController getBufferServerClient(PTOperator operator) {
        BufferServerController bsc = new BufferServerController(operator.getLogicalId());
        bsc.setToken(operator.getContainer().getBufferServerToken());
        InetSocketAddress address = operator.getContainer().bufferServerAddress;
        StreamingContainer.eventloop.connect(
                address.isUnresolved() ? new InetSocketAddress(address.getHostName(), address.getPort()) : address,
                bsc);
        return bsc;
    }

    private void purgeCheckpoints() {
        for (Pair<PTOperator, Long> p : purgeCheckpoints) {
            final PTOperator operator = p.getFirst();
            if (!operator.isOperatorStateLess()) {
                final long windowId = p.getSecond();
                Runnable r = new Runnable() {
                    @Override
                    public void run() {
                        try {
                            operator.getOperatorMeta().getValue(OperatorContext.STORAGE_AGENT)
                                    .delete(operator.getId(), windowId);
                        } catch (IOException ex) {
                            LOG.error("Failed to purge checkpoint for operator {} for windowId {}", operator,
                                    windowId, ex);
                        }
                    }
                };
                poolExecutor.submit(r);
            }
            // delete stream state when using buffer server
            for (PTOperator.PTOutput out : operator.getOutputs()) {
                if (!out.isDownStreamInline()) {
                    if (operator.getContainer().bufferServerAddress == null) {
                        // address should be null only for a new container, in which case there should not be a purge request
                        // TODO: logging added to find out how we got here
                        LOG.warn("purge request w/o buffer server address source {} container {} checkpoints {}",
                                out, operator.getContainer(), operator.checkpoints);
                        continue;
                    }

                    for (InputPortMeta ipm : out.logicalStream.getSinks()) {
                        StreamCodec<?> streamCodecInfo = StreamingContainerAgent.getStreamCodec(ipm);
                        Integer codecId = plan.getStreamCodecIdentifier(streamCodecInfo);
                        // following needs to match the concat logic in StreamingContainer
                        String sourceIdentifier = Integer.toString(operator.getId())
                                .concat(Component.CONCAT_SEPARATOR).concat(out.portName)
                                .concat(Component.CONCAT_SEPARATOR).concat(codecId.toString());
                        // delete everything from buffer server prior to new checkpoint
                        BufferServerController bsc = getBufferServerClient(operator);
                        try {
                            bsc.purge(null, sourceIdentifier, operator.checkpoints.getFirst().windowId - 1);
                        } catch (RuntimeException re) {
                            LOG.warn("Failed to purge {} {}", bsc.addr, sourceIdentifier, re);
                        }
                    }
                }
            }
        }
        purgeCheckpoints.clear();
    }

    /**
     * Mark all containers for shutdown, next container heartbeat response
     * will propagate the shutdown request. This is controlled soft shutdown.
     * If containers don't respond, the application can be forcefully terminated
     * via yarn using forceKillApplication.
     *
     * @param message
     */
    public void shutdownAllContainers(String message) {
        this.shutdownDiagnosticsMessage = message;
        LOG.info("Initiating application shutdown: {}", message);
        for (StreamingContainerAgent cs : this.containers.values()) {
            cs.shutdownRequested = true;
        }
    }

    private Map<PTContainer, List<PTOperator>> groupByContainer(Collection<PTOperator> operators) {
        Map<PTContainer, List<PTOperator>> m = new HashMap<PTContainer, List<PTOperator>>();
        for (PTOperator node : operators) {
            List<PTOperator> nodes = m.get(node.getContainer());
            if (nodes == null) {
                nodes = new ArrayList<PTOperator>();
                m.put(node.getContainer(), nodes);
            }
            nodes.add(node);
        }
        return m;
    }

    private void requestContainer(PTContainer c) {
        ContainerStartRequest dr = new ContainerStartRequest(c);
        containerStartRequests.add(dr);
        pendingAllocation.add(dr.container);
        lastResourceRequest = System.currentTimeMillis();
        for (PTOperator operator : c.getOperators()) {
            operator.setState(PTOperator.State.INACTIVE);
        }
    }

    @Override
    public void deploy(Set<PTContainer> releaseContainers, Collection<PTOperator> undeploy,
            Set<PTContainer> startContainers, Collection<PTOperator> deploy) {
        try {
            this.deployChangeInProgress.set(true);

            Map<PTContainer, List<PTOperator>> undeployGroups = groupByContainer(undeploy);

            // stop affected operators (exclude new/failed containers)
            // order does not matter, remove all operators in each container in one sweep
            for (Map.Entry<PTContainer, List<PTOperator>> e : undeployGroups.entrySet()) {
                // container may already be in failed or pending deploy state, notified by RM or timed out
                PTContainer c = e.getKey();
                if (!startContainers.contains(c) && !releaseContainers.contains(c)
                        && c.getState() != PTContainer.State.KILLED) {
                    LOG.debug("scheduling undeploy {} {}", e.getKey().getExternalId(), e.getValue());
                    for (PTOperator oper : e.getValue()) {
                        oper.setState(PTOperator.State.PENDING_UNDEPLOY);
                    }
                }
            }

            // start new containers
            for (PTContainer c : startContainers) {
                requestContainer(c);
            }

            // (re)deploy affected operators
            // can happen in parallel after buffer server for recovered publishers is reset
            Map<PTContainer, List<PTOperator>> deployGroups = groupByContainer(deploy);
            for (Map.Entry<PTContainer, List<PTOperator>> e : deployGroups.entrySet()) {
                if (!startContainers.contains(e.getKey())) {
                    // to reset publishers, clean buffer server past checkpoint so subscribers don't read stale data (including end of stream)
                    for (PTOperator operator : e.getValue()) {
                        for (PTOperator.PTOutput out : operator.getOutputs()) {
                            if (!out.isDownStreamInline()) {
                                for (InputPortMeta ipm : out.logicalStream.getSinks()) {
                                    StreamCodec<?> streamCodecInfo = StreamingContainerAgent.getStreamCodec(ipm);
                                    Integer codecId = plan.getStreamCodecIdentifier(streamCodecInfo);
                                    // following needs to match the concat logic in StreamingContainer
                                    String sourceIdentifier = Integer.toString(operator.getId())
                                            .concat(Component.CONCAT_SEPARATOR).concat(out.portName)
                                            .concat(Component.CONCAT_SEPARATOR).concat(codecId.toString());
                                    if (operator.getContainer().getState() == PTContainer.State.ACTIVE) {
                                        // TODO: unit test - find way to mock this when testing rest of logic
                                        if (operator.getContainer().bufferServerAddress.getPort() != 0) {
                                            BufferServerController bsc = getBufferServerClient(operator);
                                            // reset publisher (stale operator may still write data until disconnected)
                                            // ensures new subscriber starting to read from checkpoint will wait until publisher redeploy cycle is complete
                                            try {
                                                bsc.reset(null, sourceIdentifier, 0);
                                            } catch (Exception ex) {
                                                LOG.error("Failed to reset buffer server {} {}", sourceIdentifier,
                                                        ex);
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }

                // add to operators that we expect to deploy
                LOG.debug("scheduling deploy {} {}", e.getKey().getExternalId(), e.getValue());
                for (PTOperator oper : e.getValue()) {
                    // operator will be deployed after it has been undeployed, if still referenced by the container
                    if (oper.getState() != PTOperator.State.PENDING_UNDEPLOY) {
                        oper.setState(PTOperator.State.PENDING_DEPLOY);
                    }
                }
            }

            // stop containers that are no longer used
            for (PTContainer c : releaseContainers) {
                if (c.getExternalId() == null) {
                    continue;
                }
                StreamingContainerAgent sca = containers.get(c.getExternalId());
                if (sca != null) {
                    LOG.debug("Container marked for shutdown: {}", c);
                    // container already removed from plan
                    // TODO: monitor soft shutdown
                    sca.shutdownRequested = true;
                }
            }

        } finally {
            this.deployChangeCnt++;
            this.deployChangeInProgress.set(false);
        }
    }

    @Override
    public void recordEventAsync(StramEvent ev) {
        if (eventBus != null) {
            eventBus.publishAsync(ev);
        }
    }

    @Override
    public void dispatch(Runnable r) {
        this.eventQueue.add(r);
    }

    public OperatorInfo getOperatorInfo(int operatorId) {
        PTOperator o = this.plan.getAllOperators().get(operatorId);
        return o == null ? null : fillPhysicalOperatorInfo(o);
    }

    public List<OperatorInfo> getOperatorInfoList() {
        List<OperatorInfo> infoList = new ArrayList<OperatorInfo>();

        for (PTContainer container : this.plan.getContainers()) {
            for (PTOperator operator : container.getOperators()) {
                infoList.add(fillPhysicalOperatorInfo(operator));
            }
        }
        return infoList;
    }

    public LogicalOperatorInfo getLogicalOperatorInfo(String operatorName) {
        OperatorMeta operatorMeta = getLogicalPlan().getOperatorMeta(operatorName);
        if (operatorMeta == null) {
            return null;
        }
        return fillLogicalOperatorInfo(operatorMeta);
    }

    public ModuleMeta getModuleMeta(String moduleName) {
        return getModuleMeta(moduleName, getLogicalPlan());
    }

    private ModuleMeta getModuleMeta(String moduleName, LogicalPlan dag) {
        for (ModuleMeta m : dag.getAllModules()) {
            if (m.getFullName().equals(moduleName)) {
                return m;
            }
            ModuleMeta res = getModuleMeta(moduleName, m.getDag());
            if (res != null) {
                return res;
            }
        }
        return null;
    }

    public List<LogicalOperatorInfo> getLogicalOperatorInfoList() {
        List<LogicalOperatorInfo> infoList = new ArrayList<LogicalOperatorInfo>();
        Collection<OperatorMeta> allOperators = getLogicalPlan().getAllOperators();
        for (OperatorMeta operatorMeta : allOperators) {
            infoList.add(fillLogicalOperatorInfo(operatorMeta));
        }
        return infoList;
    }

    public OperatorAggregationInfo getOperatorAggregationInfo(String operatorName) {
        OperatorMeta operatorMeta = getLogicalPlan().getOperatorMeta(operatorName);
        if (operatorMeta == null) {
            return null;
        }
        return fillOperatorAggregationInfo(operatorMeta);
    }

    public static long toWsWindowId(long windowId) {
        // until console handles -1
        return windowId < 0 ? 0 : windowId;
    }

    private OperatorInfo fillPhysicalOperatorInfo(PTOperator operator) {
        OperatorInfo oi = new OperatorInfo();
        oi.container = operator.getContainer().getExternalId();
        oi.host = operator.getContainer().host;
        oi.id = Integer.toString(operator.getId());
        oi.name = operator.getName();
        oi.className = operator.getOperatorMeta().getOperator().getClass().getName();
        oi.status = operator.getState().toString();
        if (operator.isUnifier()) {
            oi.unifierClass = operator.getUnifierClass().getName();
        }
        oi.logicalName = operator.getOperatorMeta().getName();

        OperatorStatus os = operator.stats;
        oi.recordingId = os.recordingId;
        oi.totalTuplesProcessed = os.totalTuplesProcessed.get();
        oi.totalTuplesEmitted = os.totalTuplesEmitted.get();
        oi.tuplesProcessedPSMA = os.tuplesProcessedPSMA.get();
        oi.tuplesEmittedPSMA = os.tuplesEmittedPSMA.get();
        oi.cpuPercentageMA = os.cpuNanosPMSMA.getAvg() / 10000;
        oi.latencyMA = os.latencyMA.getAvg();
        oi.failureCount = operator.failureCount;
        oi.recoveryWindowId = toWsWindowId(operator.getRecoveryCheckpoint().windowId);
        oi.currentWindowId = toWsWindowId(os.currentWindowId.get());
        if (os.lastHeartbeat != null) {
            oi.lastHeartbeat = os.lastHeartbeat.getGeneratedTms();
        }
        if (os.checkpointStats != null) {
            oi.checkpointTime = os.checkpointStats.checkpointTime;
            oi.checkpointStartTime = os.checkpointStats.checkpointStartTime;
        }
        oi.checkpointTimeMA = os.checkpointTimeMA.getAvg();
        for (PortStatus ps : os.inputPortStatusList.values()) {
            PortInfo pinfo = new PortInfo();
            pinfo.name = ps.portName;
            pinfo.type = "input";
            pinfo.totalTuples = ps.totalTuples;
            pinfo.tuplesPSMA = Math.round(ps.tuplesPMSMA.getAvg() * 1000);
            pinfo.bufferServerBytesPSMA = Math.round(ps.bufferServerBytesPMSMA.getAvg() * 1000);
            pinfo.queueSizeMA = ps.queueSizeMA.getAvg();
            pinfo.recordingId = ps.recordingId;
            oi.addPort(pinfo);
        }
        for (PortStatus ps : os.outputPortStatusList.values()) {
            PortInfo pinfo = new PortInfo();
            pinfo.name = ps.portName;
            pinfo.type = "output";
            pinfo.totalTuples = ps.totalTuples;
            pinfo.tuplesPSMA = Math.round(ps.tuplesPMSMA.getAvg() * 1000);
            pinfo.bufferServerBytesPSMA = Math.round(ps.bufferServerBytesPMSMA.getAvg() * 1000);
            pinfo.recordingId = ps.recordingId;
            oi.addPort(pinfo);
        }
        oi.counters = os.getLastWindowedStats().size() > 0
                ? os.getLastWindowedStats().get(os.getLastWindowedStats().size() - 1).counters
                : null;

        oi.metrics = os.getLastWindowedStats().size() > 0
                ? os.getLastWindowedStats().get(os.getLastWindowedStats().size() - 1).metrics
                : null;
        return oi;
    }

    private LogicalOperatorInfo fillLogicalOperatorInfo(OperatorMeta operator) {
        LogicalOperatorInfo loi = new LogicalOperatorInfo();
        loi.name = operator.getName();
        loi.className = operator.getOperator().getClass().getName();
        loi.totalTuplesEmitted = operator.getStatus().totalTuplesEmitted;
        loi.totalTuplesProcessed = operator.getStatus().totalTuplesProcessed;
        loi.failureCount = operator.getStatus().failureCount;
        loi.status = new HashMap<String, MutableInt>();
        loi.partitions = new TreeSet<Integer>();
        loi.unifiers = new TreeSet<Integer>();
        loi.containerIds = new TreeSet<String>();
        loi.hosts = new TreeSet<String>();
        Collection<PTOperator> physicalOperators = getPhysicalPlan().getAllOperators(operator);
        NumberAggregate.LongAggregate checkpointTimeAggregate = new NumberAggregate.LongAggregate();
        for (PTOperator physicalOperator : physicalOperators) {
            OperatorStatus os = physicalOperator.stats;
            if (physicalOperator.isUnifier()) {
                loi.unifiers.add(physicalOperator.getId());
            } else {
                loi.partitions.add(physicalOperator.getId());

                // exclude unifier, not sure if we should include it in the future
                loi.tuplesEmittedPSMA += os.tuplesEmittedPSMA.get();
                loi.tuplesProcessedPSMA += os.tuplesProcessedPSMA.get();

                // calculate maximum latency for all partitions
                long latency = calculateLatency(physicalOperator);
                if (latency > loi.latencyMA) {
                    loi.latencyMA = latency;
                }
                checkpointTimeAggregate.addNumber(os.checkpointTimeMA.getAvg());
            }
            loi.cpuPercentageMA += os.cpuNanosPMSMA.getAvg() / 10000;
            if (os.lastHeartbeat != null
                    && (loi.lastHeartbeat == 0 || loi.lastHeartbeat > os.lastHeartbeat.getGeneratedTms())) {
                loi.lastHeartbeat = os.lastHeartbeat.getGeneratedTms();
            }
            long currentWindowId = toWsWindowId(os.currentWindowId.get());
            if (loi.currentWindowId == 0 || loi.currentWindowId > currentWindowId) {
                loi.currentWindowId = currentWindowId;
            }
            MutableInt count = loi.status.get(physicalOperator.getState().toString());
            if (count == null) {
                count = new MutableInt();
                loi.status.put(physicalOperator.getState().toString(), count);
            }
            count.increment();
            if (physicalOperator.getRecoveryCheckpoint() != null) {
                long recoveryWindowId = toWsWindowId(physicalOperator.getRecoveryCheckpoint().windowId);
                if (loi.recoveryWindowId == 0 || loi.recoveryWindowId > recoveryWindowId) {
                    loi.recoveryWindowId = recoveryWindowId;
                }
            }
            PTContainer container = physicalOperator.getContainer();
            if (container != null) {
                String externalId = container.getExternalId();
                if (externalId != null) {
                    loi.containerIds.add(externalId);
                    loi.hosts.add(container.host);
                }
            }
        }
        if (physicalOperators.size() > 0 && checkpointTimeAggregate.getAvg() != null) {
            loi.checkpointTimeMA = checkpointTimeAggregate.getAvg().longValue();
            loi.counters = latestLogicalCounters.get(operator.getName());
            loi.autoMetrics = latestLogicalMetrics.get(operator.getName());
        }

        return loi;
    }

    private OperatorAggregationInfo fillOperatorAggregationInfo(OperatorMeta operator) {
        OperatorAggregationInfo oai = new OperatorAggregationInfo();

        Collection<PTOperator> physicalOperators = getPhysicalPlan().getAllOperators(operator);
        if (physicalOperators.isEmpty()) {
            return null;
        }
        oai.name = operator.getName();

        for (PTOperator physicalOperator : physicalOperators) {
            if (!physicalOperator.isUnifier()) {
                OperatorStatus os = physicalOperator.stats;
                oai.latencyMA.addNumber(os.latencyMA.getAvg());
                oai.cpuPercentageMA.addNumber(os.cpuNanosPMSMA.getAvg() / 10000);
                oai.tuplesEmittedPSMA.addNumber(os.tuplesEmittedPSMA.get());
                oai.tuplesProcessedPSMA.addNumber(os.tuplesProcessedPSMA.get());
                oai.currentWindowId.addNumber(os.currentWindowId.get());
                oai.recoveryWindowId.addNumber(toWsWindowId(physicalOperator.getRecoveryCheckpoint().windowId));
                if (os.lastHeartbeat != null) {
                    oai.lastHeartbeat.addNumber(os.lastHeartbeat.getGeneratedTms());
                }
                oai.checkpointTime.addNumber(os.checkpointTimeMA.getAvg());
            }
        }
        return oai;
    }

    private long calculateLatency(PTOperator operator) {
        long latency = operator.stats.latencyMA.getAvg();
        long maxUnifierLatency = 0;
        for (PTOutput output : operator.getOutputs()) {
            for (PTInput input : output.sinks) {
                if (input.target.isUnifier()) {
                    long thisUnifierLatency = calculateLatency(input.target);
                    if (maxUnifierLatency < thisUnifierLatency) {
                        maxUnifierLatency = thisUnifierLatency;
                    }
                }
            }
        }
        return latency + maxUnifierLatency;
    }

    public List<StreamInfo> getStreamInfoList() {
        List<StreamInfo> infoList = new ArrayList<StreamInfo>();

        for (PTContainer container : this.plan.getContainers()) {
            for (PTOperator operator : container.getOperators()) {
                List<PTOutput> outputs = operator.getOutputs();
                for (PTOutput output : outputs) {
                    StreamInfo si = new StreamInfo();
                    si.logicalName = output.logicalStream.getName();
                    si.source.operatorId = String.valueOf(operator.getId());
                    si.source.portName = output.portName;
                    si.locality = output.logicalStream.getLocality();
                    for (PTInput input : output.sinks) {
                        StreamInfo.Port p = new StreamInfo.Port();
                        p.operatorId = String.valueOf(input.target.getId());
                        if (input.target.isUnifier()) {
                            p.portName = StreamingContainer.getUnifierInputPortName(input.portName,
                                    operator.getId(), output.portName);
                        } else {
                            p.portName = input.portName;
                        }
                        si.sinks.add(p);
                    }
                    infoList.add(si);
                }
            }
        }
        return infoList;
    }

    private static class RecordingRequestFilter implements Predicate<StramToNodeRequest> {
        final static Set<StramToNodeRequest.RequestType> MATCH_TYPES = Sets.newHashSet(
                StramToNodeRequest.RequestType.START_RECORDING, StramToNodeRequest.RequestType.STOP_RECORDING,
                StramToNodeRequest.RequestType.SYNC_RECORDING);

        @Override
        public boolean apply(@Nullable StramToNodeRequest input) {
            return input != null && MATCH_TYPES.contains(input.getRequestType());
        }

    }

    private class SetOperatorPropertyRequestFilter implements Predicate<StramToNodeRequest> {
        final String propertyKey;

        SetOperatorPropertyRequestFilter(String key) {
            this.propertyKey = key;
        }

        @Override
        public boolean apply(@Nullable StramToNodeRequest input) {
            if (input == null) {
                return false;
            }
            if (input instanceof StramToNodeSetPropertyRequest) {
                return ((StramToNodeSetPropertyRequest) input).getPropertyKey().equals(propertyKey);
            }
            return false;
        }

    }

    private void updateOnDeployRequests(PTOperator p, Predicate<StramToNodeRequest> superseded,
            StramToNodeRequest newRequest) {
        // filter existing requests
        List<StramToNodeRequest> cloneRequests = new ArrayList<StramToNodeRequest>(p.deployRequests.size());
        for (StramToNodeRequest existingRequest : p.deployRequests) {
            if (!superseded.apply(existingRequest)) {
                cloneRequests.add(existingRequest);
            }
        }
        // add new request, if any
        if (newRequest != null) {
            cloneRequests.add(newRequest);
        }
        p.deployRequests = Collections.unmodifiableList(cloneRequests);
    }

    private StreamingContainerAgent getContainerAgentFromOperatorId(int operatorId) {
        PTOperator oper = plan.getAllOperators().get(operatorId);
        if (oper != null) {
            StreamingContainerAgent sca = containers.get(oper.getContainer().getExternalId());
            if (sca != null) {
                return sca;
            }
        }
        // throw exception that propagates to web client
        throw new NotFoundException("Operator ID " + operatorId + " not found");
    }

    public void startRecording(String id, int operId, String portName, long numWindows) {
        StreamingContainerAgent sca = getContainerAgentFromOperatorId(operId);
        StramToNodeStartRecordingRequest request = new StramToNodeStartRecordingRequest();
        request.setOperatorId(operId);
        if (!StringUtils.isBlank(portName)) {
            request.setPortName(portName);
        }
        request.setNumWindows(numWindows);
        request.setId(id);
        sca.addOperatorRequest(request);
        PTOperator operator = plan.getAllOperators().get(operId);
        if (operator != null) {
            // restart on deploy
            updateOnDeployRequests(operator, new RecordingRequestFilter(), request);
        }
    }

    public void stopRecording(int operId, String portName) {
        StreamingContainerAgent sca = getContainerAgentFromOperatorId(operId);
        StramToNodeRequest request = new StramToNodeRequest();
        request.setOperatorId(operId);
        if (!StringUtils.isBlank(portName)) {
            request.setPortName(portName);
        }
        request.setRequestType(StramToNodeRequest.RequestType.STOP_RECORDING);
        sca.addOperatorRequest(request);
        PTOperator operator = plan.getAllOperators().get(operId);
        if (operator != null) {
            // no stop on deploy, but remove existing start
            updateOnDeployRequests(operator, new RecordingRequestFilter(), null);
        }
    }

    public void syncStats() {
        statsRecorder.requestSync();
    }

    public void syncEvents() {
        eventRecorder.requestSync();
    }

    public void stopContainer(String containerId) {
        this.containerStopRequests.put(containerId, containerId);
    }

    public Recoverable getSetOperatorProperty(String operatorName, String propertyName, String propertyValue) {
        return new SetOperatorProperty(operatorName, propertyName, propertyValue);
    }

    public Recoverable getSetPhysicalOperatorProperty(int operatorId, String propertyName, String propertyValue) {
        return new SetPhysicalOperatorProperty(operatorId, propertyName, propertyValue);
    }

    public void setOperatorProperty(String operatorName, String propertyName, String propertyValue) {
        OperatorMeta logicalOperator = plan.getLogicalPlan().getOperatorMeta(operatorName);
        if (logicalOperator == null) {
            throw new IllegalArgumentException("Unknown operator " + operatorName);
        }

        writeJournal(new SetOperatorProperty(operatorName, propertyName, propertyValue));

        setOperatorProperty(logicalOperator, propertyName, propertyValue);
    }

    private void setOperatorProperty(OperatorMeta logicalOperator, String propertyName, String propertyValue) {
        Map<String, String> properties = Collections.singletonMap(propertyName, propertyValue);
        LogicalPlanConfiguration.setOperatorProperties(logicalOperator.getOperator(), properties);

        List<PTOperator> operators = plan.getOperators(logicalOperator);
        for (PTOperator o : operators) {
            StramToNodeSetPropertyRequest request = new StramToNodeSetPropertyRequest();
            request.setOperatorId(o.getId());
            request.setPropertyKey(propertyName);
            request.setPropertyValue(propertyValue);
            addOperatorRequest(o, request);
            // re-apply to checkpointed state on deploy
            updateOnDeployRequests(o, new SetOperatorPropertyRequestFilter(propertyName), request);
        }
        // should probably not record it here because it's better to get confirmation from the operators first.
        // but right now, the operators do not give confirmation for the requests.  so record it here for now.
        recordEventAsync(
                new StramEvent.SetOperatorPropertyEvent(logicalOperator.getName(), propertyName, propertyValue));
    }

    /**
     * Set property on a physical operator. The property change is applied asynchronously on the deployed operator.
     *
     * @param operatorId
     * @param propertyName
     * @param propertyValue
     */
    public void setPhysicalOperatorProperty(int operatorId, String propertyName, String propertyValue) {
        PTOperator o = this.plan.getAllOperators().get(operatorId);
        if (o == null) {
            return;
        }
        writeJournal(new SetPhysicalOperatorProperty(operatorId, propertyName, propertyValue));
        setPhysicalOperatorProperty(o, propertyName, propertyValue);
    }

    private void setPhysicalOperatorProperty(PTOperator o, String propertyName, String propertyValue) {
        String operatorName = o.getName();
        StramToNodeSetPropertyRequest request = new StramToNodeSetPropertyRequest();
        request.setOperatorId(o.getId());
        request.setPropertyKey(propertyName);
        request.setPropertyValue(propertyValue);
        addOperatorRequest(o, request);
        updateOnDeployRequests(o, new SetOperatorPropertyRequestFilter(propertyName), request);

        // should probably not record it here because it's better to get confirmation from the operators first.
        // but right now, the operators do not give confirmation for the requests. so record it here for now.
        recordEventAsync(new StramEvent.SetPhysicalOperatorPropertyEvent(operatorName, o.getId(), propertyName,
                propertyValue));
    }

    @Override
    public void addOperatorRequest(PTOperator oper, StramToNodeRequest request) {
        StreamingContainerAgent sca = getContainerAgent(oper.getContainer().getExternalId());
        // yarn may not assigned resource to the container yet
        if (sca != null) {
            sca.addOperatorRequest(request);
        }
    }

    /**
     * Send requests to change logger levels to all containers
     *
     * @param changedLoggers loggers that were changed.
     */
    public void setLoggersLevel(Map<String, String> changedLoggers) {
        LOG.debug("change logger request");
        StramToNodeChangeLoggersRequest request = new StramToNodeChangeLoggersRequest();
        request.setTargetChanges(changedLoggers);
        for (StreamingContainerAgent stramChildAgent : containers.values()) {
            stramChildAgent.addOperatorRequest(request);
        }
    }

    public FutureTask<Object> getPhysicalOperatorProperty(int operatorId, String propertyName, long waitTime) {
        PTOperator o = this.plan.getAllOperators().get(operatorId);
        StramToNodeGetPropertyRequest request = new StramToNodeGetPropertyRequest();
        request.setOperatorId(operatorId);
        request.setPropertyName(propertyName);
        addOperatorRequest(o, request);
        RequestHandler task = new RequestHandler();
        task.requestId = nodeToStramRequestIds.incrementAndGet();
        task.waitTime = waitTime;
        request.requestId = task.requestId;
        FutureTask<Object> future = new FutureTask<Object>(task);
        dispatch(future);
        return future;
    }

    public Attribute.AttributeMap getApplicationAttributes() {
        LogicalPlan lp = getLogicalPlan();
        try {
            return lp.getAttributes().clone();
        } catch (CloneNotSupportedException ex) {
            throw new RuntimeException("Cannot clone DAG attributes", ex);
        }
    }

    public Attribute.AttributeMap getOperatorAttributes(String operatorId) {
        OperatorMeta logicalOperator = plan.getLogicalPlan().getOperatorMeta(operatorId);
        if (logicalOperator == null) {
            throw new IllegalArgumentException("Invalid operatorId " + operatorId);
        }
        try {
            return logicalOperator.getAttributes().clone();
        } catch (CloneNotSupportedException ex) {
            throw new RuntimeException("Cannot clone operator attributes", ex);
        }
    }

    public Attribute.AttributeMap getPortAttributes(String operatorId, String portName) {
        OperatorMeta logicalOperator = plan.getLogicalPlan().getOperatorMeta(operatorId);
        if (logicalOperator == null) {
            throw new IllegalArgumentException("Invalid operatorId " + operatorId);
        }

        Operators.PortMappingDescriptor portMap = new Operators.PortMappingDescriptor();
        Operators.describe(logicalOperator.getOperator(), portMap);
        PortContextPair<InputPort<?>> inputPort = portMap.inputPorts.get(portName);
        if (inputPort != null) {
            InputPortMeta portMeta = logicalOperator.getMeta(inputPort.component);
            try {
                return portMeta.getAttributes().clone();
            } catch (CloneNotSupportedException ex) {
                throw new RuntimeException("Cannot clone port attributes", ex);
            }
        } else {
            PortContextPair<OutputPort<?>> outputPort = portMap.outputPorts.get(portName);
            if (outputPort != null) {
                OutputPortMeta portMeta = logicalOperator.getMeta(outputPort.component);
                try {
                    return portMeta.getAttributes().clone();
                } catch (CloneNotSupportedException ex) {
                    throw new RuntimeException("Cannot clone port attributes", ex);
                }
            }
            throw new IllegalArgumentException("Invalid port name " + portName);
        }
    }

    public LogicalPlan getLogicalPlan() {
        return plan.getLogicalPlan();
    }

    /**
     * Asynchronously process the logical, physical plan and execution layer changes.
     * Caller can use the returned future to block until processing is complete.
     *
     * @param requests
     * @return future
     * @throws Exception
     */
    public FutureTask<Object> logicalPlanModification(List<LogicalPlanRequest> requests) throws Exception {
        // delegate processing to dispatch thread
        FutureTask<Object> future = new FutureTask<Object>(new LogicalPlanChangeRunnable(requests));
        dispatch(future);
        //LOG.info("Scheduled plan changes: {}", requests);
        return future;
    }

    private class LogicalPlanChangeRunnable implements java.util.concurrent.Callable<Object> {
        final List<LogicalPlanRequest> requests;

        private LogicalPlanChangeRunnable(List<LogicalPlanRequest> requests) {
            this.requests = requests;
        }

        @Override
        public Object call() throws Exception {
            // clone logical plan, for dry run and validation
            LOG.info("Begin plan changes: {}", requests);
            LogicalPlan lp = plan.getLogicalPlan();
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            LogicalPlan.write(lp, bos);
            bos.flush();
            ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
            lp = LogicalPlan.read(bis);

            PlanModifier pm = new PlanModifier(lp);
            for (LogicalPlanRequest request : requests) {
                LOG.debug("Dry run plan change: {}", request);
                request.execute(pm);
            }

            lp.validate();

            // perform changes on live plan
            pm = new PlanModifier(plan);
            for (LogicalPlanRequest request : requests) {
                request.execute(pm);

                // record an event for the request.  however, we should probably record these when we get a confirmation.
                recordEventAsync(new StramEvent.ChangeLogicalPlanEvent(request));
            }
            pm.applyChanges(StreamingContainerManager.this);
            LOG.info("Plan changes applied: {}", requests);
            return null;
        }

    }

    public CriticalPathInfo getCriticalPathInfo() {
        return criticalPathInfo;
    }

    private void checkpoint() throws IOException {
        if (recoveryHandler != null) {
            LOG.debug("Checkpointing state");
            DataOutputStream out = recoveryHandler.rotateLog();
            journal.setOutputStream(out);
            // checkpoint the state
            CheckpointState cs = new CheckpointState();
            cs.finals = this.vars;
            cs.physicalPlan = this.plan;
            recoveryHandler.save(cs);
        }
    }

    @Override
    public void writeJournal(Recoverable operation) {
        try {
            if (journal != null) {
                journal.write(operation);
            }
        } catch (Exception e) {
            throw new IllegalStateException("Failed to write to journal " + operation, e);
        }
    }

    /**
     * Get the instance for the given application. If the application directory contains a checkpoint, the state will be restored.
     *
     * @param rh
     * @param dag
     * @param enableEventRecording
     * @return instance of {@link StreamingContainerManager}
     * @throws IOException
     */
    public static StreamingContainerManager getInstance(RecoveryHandler rh, LogicalPlan dag,
            boolean enableEventRecording) throws IOException {
        try {
            CheckpointState checkpointedState = (CheckpointState) rh.restore();
            StreamingContainerManager scm;
            if (checkpointedState == null) {
                scm = new StreamingContainerManager(dag, enableEventRecording, new SystemClock());
            } else {
                // find better way to support final transient members
                PhysicalPlan plan = checkpointedState.physicalPlan;
                plan.getLogicalPlan().setAttribute(LogicalPlan.APPLICATION_ATTEMPT_ID,
                        dag.getAttributes().get(LogicalPlan.APPLICATION_ATTEMPT_ID));
                scm = new StreamingContainerManager(checkpointedState, enableEventRecording);
                for (Field f : plan.getClass().getDeclaredFields()) {
                    if (f.getType() == PlanContext.class) {
                        f.setAccessible(true);
                        try {
                            f.set(plan, scm);
                        } catch (Exception e) {
                            throw new RuntimeException("Failed to set " + f, e);
                        }
                        f.setAccessible(false);
                    }
                }
                DataInputStream logStream = rh.getLog();
                scm.journal.replay(logStream);
                logStream.close();

                // restore checkpoint info
                plan.syncCheckpoints(scm.vars.windowStartMillis, scm.clock.getTime());
                scm.committedWindowId = scm.updateCheckpoints(true);

                // at this point the physical plan has been fully restored
                // populate container agents for existing containers
                for (PTContainer c : plan.getContainers()) {
                    if (c.getExternalId() != null) {
                        LOG.debug("Restore container agent {} for {}", c.getExternalId(), c);
                        StreamingContainerAgent sca = new StreamingContainerAgent(c,
                                scm.newStreamingContainerContext(c), scm);
                        scm.containers.put(c.getExternalId(), sca);
                    } else {
                        LOG.debug("Requesting new resource for {}", c.toIdStateString());
                        scm.requestContainer(c);
                    }
                }
            }
            scm.recoveryHandler = rh;
            scm.checkpoint();
            return scm;
        } catch (IOException e) {
            throw new IllegalStateException("Failed to read checkpointed state", e);
        }
    }

    private static class FinalVars implements java.io.Serializable {
        private static final long serialVersionUID = 3827310557521807024L;
        private final long windowStartMillis;
        private final int heartbeatTimeoutMillis;
        private final String appPath;
        private final int maxWindowsBehindForStats;
        private final boolean enableStatsRecording;
        private final int rpcLatencyCompensationSamples;

        private FinalVars(LogicalPlan dag, long tms) {
            Attribute.AttributeMap attributes = dag.getAttributes();
            /* try to align to it to please eyes. */
            windowStartMillis = tms - (tms % 1000);

            if (attributes.get(LogicalPlan.APPLICATION_PATH) == null) {
                throw new IllegalArgumentException("Not set: " + LogicalPlan.APPLICATION_PATH);
            }

            this.appPath = attributes.get(LogicalPlan.APPLICATION_PATH);

            if (attributes.get(LogicalPlan.STREAMING_WINDOW_SIZE_MILLIS) == null) {
                attributes.put(LogicalPlan.STREAMING_WINDOW_SIZE_MILLIS, 500);
            }
            if (attributes.get(LogicalPlan.CHECKPOINT_WINDOW_COUNT) == null) {
                attributes.put(LogicalPlan.CHECKPOINT_WINDOW_COUNT,
                        30000 / attributes.get(LogicalPlan.STREAMING_WINDOW_SIZE_MILLIS));
            }

            this.heartbeatTimeoutMillis = dag.getValue(LogicalPlan.HEARTBEAT_TIMEOUT_MILLIS);
            this.maxWindowsBehindForStats = dag.getValue(LogicalPlan.STATS_MAX_ALLOWABLE_WINDOWS_LAG);
            this.enableStatsRecording = dag.getValue(LogicalPlan.ENABLE_STATS_RECORDING);
            this.rpcLatencyCompensationSamples = dag.getValue(LogicalPlan.RPC_LATENCY_COMPENSATION_SAMPLES);
        }

        private FinalVars(FinalVars other, LogicalPlan dag) {
            this.windowStartMillis = other.windowStartMillis;
            this.heartbeatTimeoutMillis = other.heartbeatTimeoutMillis;
            this.maxWindowsBehindForStats = other.maxWindowsBehindForStats;
            this.enableStatsRecording = other.enableStatsRecording;
            this.appPath = dag.getValue(LogicalPlan.APPLICATION_PATH);
            this.rpcLatencyCompensationSamples = other.rpcLatencyCompensationSamples;
        }

    }

    /**
     * The state that can be saved and used to recover the manager.
     */
    static class CheckpointState implements Serializable {
        private static final long serialVersionUID = 3827310557521807024L;
        private FinalVars finals;
        private PhysicalPlan physicalPlan;

        /**
         * Modify previously saved state to allow for re-launch of application.
         */
        public void setApplicationId(LogicalPlan newApp, Configuration conf) {
            LogicalPlan lp = physicalPlan.getLogicalPlan();
            String appId = newApp.getValue(LogicalPlan.APPLICATION_ID);
            String oldAppId = lp.getValue(LogicalPlan.APPLICATION_ID);
            if (oldAppId == null) {
                throw new AssertionError("Missing original application id");
            }

            lp.setAttribute(LogicalPlan.APPLICATION_ID, appId);
            lp.setAttribute(LogicalPlan.APPLICATION_PATH, newApp.assertAppPath());
            lp.setAttribute(LogicalPlan.LIBRARY_JARS, newApp.getValue(LogicalPlan.LIBRARY_JARS));
            lp.setAttribute(LogicalPlan.ARCHIVES, newApp.getValue(LogicalPlan.ARCHIVES));

            this.finals = new FinalVars(finals, lp);
            StorageAgent sa = lp.getValue(OperatorContext.STORAGE_AGENT);
            if (sa instanceof AsyncFSStorageAgent) {
                // replace the default storage agent, if present
                AsyncFSStorageAgent fssa = (AsyncFSStorageAgent) sa;
                if (fssa.path.contains(oldAppId)) {
                    fssa = new AsyncFSStorageAgent(fssa.path.replace(oldAppId, appId), conf);
                    lp.setAttribute(OperatorContext.STORAGE_AGENT, fssa);
                }
            } else if (sa instanceof FSStorageAgent) {
                // replace the default storage agent, if present
                FSStorageAgent fssa = (FSStorageAgent) sa;
                if (fssa.path.contains(oldAppId)) {
                    fssa = new FSStorageAgent(fssa.path.replace(oldAppId, appId), conf);
                    lp.setAttribute(OperatorContext.STORAGE_AGENT, fssa);
                }
            }
        }

    }

    public interface RecoveryHandler {
        /**
         * Save snapshot.
         *
         * @param state
         * @throws IOException
         */
        void save(Object state) throws IOException;

        /**
         * Restore snapshot. Must get/apply log after restore.
         *
         * @return snapshot
         * @throws IOException
         */
        Object restore() throws IOException;

        /**
         * Backup log. Call before save.
         *
         * @return output stream
         * @throws IOException
         */
        DataOutputStream rotateLog() throws IOException;

        /**
         * Get input stream for log. Call after restore.
         *
         * @return input stream
         * @throws IOException
         */
        DataInputStream getLog() throws IOException;

    }

    private class RequestHandler implements Callable<Object> {
        /*
         * The unique requestId of the request
         */
        public long requestId;
        /*
         * The maximum time this thread will wait for the response
         */
        public long waitTime = 5000;

        @Override
        @SuppressWarnings("SleepWhileInLoop")
        public Object call() throws Exception {
            Object obj;
            long expiryTime = System.currentTimeMillis() + waitTime;
            while ((obj = commandResponse.getIfPresent(requestId)) == null
                    && expiryTime > System.currentTimeMillis()) {
                Thread.sleep(100);
                LOG.debug("Polling for a response to request with Id {}", requestId);
            }
            if (obj != null) {
                commandResponse.invalidate(requestId);
                return obj;
            }
            return null;
        }
    }

    @VisibleForTesting
    protected Collection<Pair<Long, Map<String, Object>>> getLogicalMetrics(String operatorName) {
        if (logicalMetrics.get(operatorName) != null) {
            return Collections.unmodifiableCollection(logicalMetrics.get(operatorName));
        }
        return null;
    }

    @VisibleForTesting
    protected Object getLogicalCounter(String operatorName) {
        return latestLogicalCounters.get(operatorName);
    }

}