com.cloudera.llama.am.impl.PhasingOutRMConnector.java Source code

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Here is the source code for com.cloudera.llama.am.impl.PhasingOutRMConnector.java

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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.cloudera.llama.am.impl;

import com.cloudera.llama.am.api.LlamaAM;
import com.cloudera.llama.am.api.NodeInfo;
import com.cloudera.llama.am.spi.RMConnector;
import com.cloudera.llama.am.spi.RMListener;
import com.cloudera.llama.am.spi.RMResource;
import com.cloudera.llama.util.LlamaException;
import com.cloudera.llama.util.UUID;
import com.codahale.metrics.MetricRegistry;
import org.apache.hadoop.conf.Configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

/**
 * <code>PhasingOutRMConnector</code> implementation that handles the token expiry
 * issue in RM.
 */
/**
 * <code>PhasingOutRMConnector</code> implementation that handles the token
 * expiry issue in RM. It recycles the underneath RM connector after a fixed
 * interval.
 * <p/>
 * The following property drive the logic of this class:
 * <ul>
 * <li>{@link LlamaAM#RM_CONNECTOR_RECYCLE_INTERVAL_KEY}</li>
 * </ul>
 */

public class PhasingOutRMConnector implements RMConnector, Runnable {
    private static final Logger LOG = LoggerFactory.getLogger(PhasingOutRMConnector.class);
    private final ScheduledFuture<?> future;
    private final RmConnectorCreator newConnectorCreator;

    private Configuration conf;
    private MetricRegistry metricRegistry;
    private RMListener listener;

    private RMConnector active;
    private RMConnector previous;

    synchronized RMConnector[] getConnectors() {
        if (previous != null) {
            return new RMConnector[] { active, previous };
        } else {
            return new RMConnector[] { active };
        }
    }

    public interface RmConnectorCreator {
        RMConnector create();
    };

    public PhasingOutRMConnector(Configuration conf, ScheduledExecutorService stp,
            RmConnectorCreator newConnectorCreator) throws LlamaException {
        this.conf = conf;
        this.newConnectorCreator = newConnectorCreator;
        this.active = newConnectorCreator.create();

        long interval = conf.getLong(LlamaAM.RM_CONNECTOR_RECYCLE_INTERVAL_KEY,
                LlamaAM.RM_CONNECTOR_RECYCLE_INTERVAL_DEFAULT);
        this.future = stp.scheduleAtFixedRate(this, interval, interval, TimeUnit.MINUTES);
    }

    @Override
    public void setMetricRegistry(MetricRegistry metricRegistry) {
        this.metricRegistry = metricRegistry;
        for (RMConnector connector : getConnectors()) {
            connector.setMetricRegistry(metricRegistry);
        }
    }

    @Override
    public boolean hasResources() {
        for (RMConnector connector : getConnectors()) {
            if (connector.hasResources()) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void deleteAllReservations() throws LlamaException {
        active.deleteAllReservations();
    }

    @Override
    public void setRMListener(RMListener listener) {
        this.listener = listener;
        for (RMConnector connector : getConnectors()) {
            connector.setRMListener(listener);
        }
    }

    @Override
    public void start() throws LlamaException {
        active.start();

    }

    @Override
    public void stop() {
        for (RMConnector connector : getConnectors()) {
            connector.stop();
        }
        future.cancel(true);
    }

    @Override
    public void register(String queue) throws LlamaException {
        active.register(queue);
    }

    @Override
    public void unregister() {
        for (RMConnector connector : getConnectors()) {
            connector.unregister();
        }
    }

    @Override
    public List<NodeInfo> getNodes() throws LlamaException {
        return active.getNodes();
    }

    @Override
    public void reserve(Collection<RMResource> resources) throws LlamaException {
        active.reserve(resources);
    }

    @Override
    public void release(Collection<RMResource> resources, boolean doNotCache) throws LlamaException {
        for (RMConnector connector : getConnectors()) {
            connector.release(resources, doNotCache);
            doNotCache = true;
        }
    }

    @Override
    public boolean reassignResource(Object rmResourceId, UUID resourceId) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void emptyCache() throws LlamaException {
        for (RMConnector connector : getConnectors()) {
            connector.emptyCache();
        }
    }

    public RMConnector getConnector() {
        return this.active;
    }

    @Override
    public void run() {
        LOG.trace("Running the phaseout for RM connector");
        // We need to create a new connector and discard the old one.
        RMConnector newConnector = null;
        newConnector = newConnectorCreator.create();
        newConnector.setRMListener(listener);
        newConnector.setMetricRegistry(metricRegistry);

        List<RMConnector> oldConnectors = new ArrayList<RMConnector>();
        synchronized (this) {
            oldConnectors.add(previous);
            if (!active.hasResources()) {
                oldConnectors.add(active);
                active = null;
            }
            previous = active;
            active = newConnector;
        }
        for (RMConnector old : oldConnectors) {
            if (old != null) {
                if (old.hasResources()) {
                    LOG.warn("The previous RMConnector for queue still has resources which "
                            + "were not released yet.");
                }
                LOG.trace("Stopping the old RM connector {}.", old);
                old.stop();
            }
        }
    }
}