Java tutorial
/* * Druid - a distributed column store. * Copyright (C) 2012 Metamarkets Group Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ package com.metamx.druid.realtime.plumber; import com.fasterxml.jackson.annotation.JacksonInject; import com.fasterxml.jackson.annotation.JsonCreator; import com.fasterxml.jackson.annotation.JsonProperty; import com.google.common.base.Function; import com.google.common.base.Joiner; import com.google.common.base.Preconditions; import com.google.common.base.Predicates; import com.google.common.base.Throwables; import com.google.common.collect.Iterables; import com.google.common.collect.Lists; import com.google.common.collect.Maps; import com.google.common.primitives.Ints; import com.google.common.util.concurrent.ListeningExecutorService; import com.google.common.util.concurrent.MoreExecutors; import com.google.common.util.concurrent.ThreadFactoryBuilder; import com.metamx.common.Pair; import com.metamx.common.concurrent.ScheduledExecutors; import com.metamx.common.guava.FunctionalIterable; import com.metamx.druid.Query; import com.metamx.druid.TimelineObjectHolder; import com.metamx.druid.VersionedIntervalTimeline; import com.metamx.druid.client.DataSegment; import com.metamx.druid.client.DruidServer; import com.metamx.druid.client.ServerView; import com.metamx.druid.coordination.DataSegmentAnnouncer; import com.metamx.druid.guava.ThreadRenamingCallable; import com.metamx.druid.guava.ThreadRenamingRunnable; import com.metamx.druid.index.QueryableIndex; import com.metamx.druid.index.QueryableIndexSegment; import com.metamx.druid.index.Segment; import com.metamx.druid.index.v1.IndexGranularity; import com.metamx.druid.index.v1.IndexIO; import com.metamx.druid.index.v1.IndexMerger; import com.metamx.druid.loading.DataSegmentPusher; import com.metamx.druid.partition.SingleElementPartitionChunk; import com.metamx.druid.query.MetricsEmittingQueryRunner; import com.metamx.druid.query.QueryRunner; import com.metamx.druid.query.QueryRunnerFactory; import com.metamx.druid.query.QueryRunnerFactoryConglomerate; import com.metamx.druid.query.QueryToolChest; import com.metamx.druid.query.segment.SegmentDescriptor; import com.metamx.druid.query.segment.SpecificSegmentQueryRunner; import com.metamx.druid.query.segment.SpecificSegmentSpec; import com.metamx.druid.realtime.FireDepartmentMetrics; import com.metamx.druid.realtime.FireHydrant; import com.metamx.druid.realtime.Schema; import com.metamx.druid.realtime.SegmentPublisher; import com.metamx.emitter.EmittingLogger; import com.metamx.emitter.service.ServiceEmitter; import com.metamx.emitter.service.ServiceMetricEvent; import org.apache.commons.io.FileUtils; import org.joda.time.DateTime; import org.joda.time.Duration; import org.joda.time.Interval; import org.joda.time.Period; import javax.annotation.Nullable; import java.io.File; import java.io.FilenameFilter; import java.io.IOException; import java.util.Arrays; import java.util.Comparator; import java.util.List; import java.util.Map; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; /** */ public class RealtimePlumberSchool implements PlumberSchool { private static final EmittingLogger log = new EmittingLogger(RealtimePlumberSchool.class); private static final ListeningExecutorService EXEC = MoreExecutors.sameThreadExecutor(); private final Period windowPeriod; private final File basePersistDirectory; private final IndexGranularity segmentGranularity; private final Object handoffCondition = new Object(); private ServiceEmitter emitter; private volatile VersioningPolicy versioningPolicy = null; private volatile RejectionPolicyFactory rejectionPolicyFactory = null; private volatile QueryRunnerFactoryConglomerate conglomerate = null; private volatile DataSegmentPusher dataSegmentPusher = null; private volatile DataSegmentAnnouncer segmentAnnouncer = null; private volatile SegmentPublisher segmentPublisher = null; private volatile ServerView serverView = null; @JsonCreator public RealtimePlumberSchool(@JsonProperty("windowPeriod") Period windowPeriod, @JsonProperty("basePersistDirectory") File basePersistDirectory, @JsonProperty("segmentGranularity") IndexGranularity segmentGranularity) { this.windowPeriod = windowPeriod; this.basePersistDirectory = basePersistDirectory; this.segmentGranularity = segmentGranularity; this.versioningPolicy = new IntervalStartVersioningPolicy(); this.rejectionPolicyFactory = new ServerTimeRejectionPolicyFactory(); Preconditions.checkNotNull(windowPeriod, "RealtimePlumberSchool requires a windowPeriod."); Preconditions.checkNotNull(basePersistDirectory, "RealtimePlumberSchool requires a basePersistDirectory."); Preconditions.checkNotNull(segmentGranularity, "RealtimePlumberSchool requires a segmentGranularity."); } @JsonProperty("versioningPolicy") public void setVersioningPolicy(VersioningPolicy versioningPolicy) { this.versioningPolicy = versioningPolicy; } @JsonProperty("rejectionPolicy") public void setRejectionPolicyFactory(RejectionPolicyFactory factory) { this.rejectionPolicyFactory = factory; } @JacksonInject("queryRunnerFactoryConglomerate") public void setConglomerate(QueryRunnerFactoryConglomerate conglomerate) { this.conglomerate = conglomerate; } @JacksonInject("segmentPusher") public void setDataSegmentPusher(DataSegmentPusher dataSegmentPusher) { this.dataSegmentPusher = dataSegmentPusher; } @JacksonInject("segmentAnnouncer") public void setSegmentAnnouncer(DataSegmentAnnouncer segmentAnnouncer) { this.segmentAnnouncer = segmentAnnouncer; } @JacksonInject("segmentPublisher") public void setSegmentPublisher(SegmentPublisher segmentPublisher) { this.segmentPublisher = segmentPublisher; } @JacksonInject("serverView") public void setServerView(ServerView serverView) { this.serverView = serverView; } @JacksonInject("serviceEmitter") public void setServiceEmitter(ServiceEmitter emitter) { this.emitter = emitter; } @Override public Plumber findPlumber(final Schema schema, final FireDepartmentMetrics metrics) { verifyState(); final RejectionPolicy rejectionPolicy = rejectionPolicyFactory.create(windowPeriod); log.info("Creating plumber using rejectionPolicy[%s]", rejectionPolicy); return new Plumber() { private volatile boolean stopped = false; private volatile ExecutorService persistExecutor = null; private volatile ScheduledExecutorService scheduledExecutor = null; private final Map<Long, Sink> sinks = Maps.newConcurrentMap(); private final VersionedIntervalTimeline<String, Sink> sinkTimeline = new VersionedIntervalTimeline<String, Sink>( String.CASE_INSENSITIVE_ORDER); @Override public void startJob() { computeBaseDir(schema).mkdirs(); initializeExecutors(); bootstrapSinksFromDisk(); registerServerViewCallback(); startPersistThread(); } @Override public Sink getSink(long timestamp) { if (!rejectionPolicy.accept(timestamp)) { return null; } final long truncatedTime = segmentGranularity.truncate(timestamp); Sink retVal = sinks.get(truncatedTime); if (retVal == null) { final Interval sinkInterval = new Interval(new DateTime(truncatedTime), segmentGranularity.increment(new DateTime(truncatedTime))); retVal = new Sink(sinkInterval, schema, versioningPolicy.getVersion(sinkInterval)); try { segmentAnnouncer.announceSegment(retVal.getSegment()); sinks.put(truncatedTime, retVal); sinkTimeline.add(retVal.getInterval(), retVal.getVersion(), new SingleElementPartitionChunk<Sink>(retVal)); } catch (IOException e) { log.makeAlert(e, "Failed to announce new segment[%s]", schema.getDataSource()) .addData("interval", retVal.getInterval()).emit(); } } return retVal; } @Override public <T> QueryRunner<T> getQueryRunner(final Query<T> query) { final QueryRunnerFactory<T, Query<T>> factory = conglomerate.findFactory(query); final QueryToolChest<T, Query<T>> toolchest = factory.getToolchest(); final Function<Query<T>, ServiceMetricEvent.Builder> builderFn = new Function<Query<T>, ServiceMetricEvent.Builder>() { @Override public ServiceMetricEvent.Builder apply(@Nullable Query<T> input) { return toolchest.makeMetricBuilder(query); } }; List<TimelineObjectHolder<String, Sink>> querySinks = Lists.newArrayList(); for (Interval interval : query.getIntervals()) { querySinks.addAll(sinkTimeline.lookup(interval)); } return toolchest.mergeResults(factory.mergeRunners(EXEC, FunctionalIterable.create(querySinks) .transform(new Function<TimelineObjectHolder<String, Sink>, QueryRunner<T>>() { @Override public QueryRunner<T> apply(TimelineObjectHolder<String, Sink> holder) { final Sink theSink = holder.getObject().getChunk(0).getObject(); return new SpecificSegmentQueryRunner<T>(new MetricsEmittingQueryRunner<T>(emitter, builderFn, factory.mergeRunners(EXEC, Iterables.transform(theSink, new Function<FireHydrant, QueryRunner<T>>() { @Override public QueryRunner<T> apply(FireHydrant input) { return factory.createRunner(input.getSegment()); } }))), new SpecificSegmentSpec(new SegmentDescriptor(holder.getInterval(), theSink.getSegment().getVersion(), theSink.getSegment().getShardSpec().getPartitionNum()))); } }))); } @Override public void persist(final Runnable commitRunnable) { final List<Pair<FireHydrant, Interval>> indexesToPersist = Lists.newArrayList(); for (Sink sink : sinks.values()) { if (sink.swappable()) { indexesToPersist.add(Pair.of(sink.swap(), sink.getInterval())); } } log.info("Submitting persist runnable for dataSource[%s]", schema.getDataSource()); persistExecutor.execute(new ThreadRenamingRunnable( String.format("%s-incremental-persist", schema.getDataSource())) { @Override public void doRun() { for (Pair<FireHydrant, Interval> pair : indexesToPersist) { metrics.incrementRowOutputCount(persistHydrant(pair.lhs, schema, pair.rhs)); } commitRunnable.run(); } }); } // Submits persist-n-merge task for a Sink to the persistExecutor private void persistAndMerge(final long truncatedTime, final Sink sink) { final String threadName = String.format("%s-%s-persist-n-merge", schema.getDataSource(), new DateTime(truncatedTime)); persistExecutor.execute(new ThreadRenamingRunnable(threadName) { @Override public void doRun() { final Interval interval = sink.getInterval(); for (FireHydrant hydrant : sink) { if (!hydrant.hasSwapped()) { log.info("Hydrant[%s] hasn't swapped yet, swapping. Sink[%s]", hydrant, sink); final int rowCount = persistHydrant(hydrant, schema, interval); metrics.incrementRowOutputCount(rowCount); } } final File mergedTarget = new File(computePersistDir(schema, interval), "merged"); if (mergedTarget.exists()) { log.info("Skipping already-merged sink: %s", sink); return; } File mergedFile = null; try { List<QueryableIndex> indexes = Lists.newArrayList(); for (FireHydrant fireHydrant : sink) { Segment segment = fireHydrant.getSegment(); final QueryableIndex queryableIndex = segment.asQueryableIndex(); log.info("Adding hydrant[%s]", fireHydrant); indexes.add(queryableIndex); } mergedFile = IndexMerger.mergeQueryableIndex(indexes, schema.getAggregators(), mergedTarget); QueryableIndex index = IndexIO.loadIndex(mergedFile); DataSegment segment = dataSegmentPusher.push(mergedFile, sink.getSegment() .withDimensions(Lists.newArrayList(index.getAvailableDimensions()))); segmentPublisher.publishSegment(segment); } catch (IOException e) { log.makeAlert(e, "Failed to persist merged index[%s]", schema.getDataSource()) .addData("interval", interval).emit(); } if (mergedFile != null) { try { if (mergedFile != null) { log.info("Deleting Index File[%s]", mergedFile); FileUtils.deleteDirectory(mergedFile); } } catch (IOException e) { log.warn(e, "Error deleting directory[%s]", mergedFile); } } } }); } @Override public void finishJob() { log.info("Shutting down..."); for (final Map.Entry<Long, Sink> entry : sinks.entrySet()) { persistAndMerge(entry.getKey(), entry.getValue()); } while (!sinks.isEmpty()) { try { log.info("Cannot shut down yet! Sinks remaining: %s", Joiner.on(", ") .join(Iterables.transform(sinks.values(), new Function<Sink, String>() { @Override public String apply(Sink input) { return input.getSegment().getIdentifier(); } }))); synchronized (handoffCondition) { while (!sinks.isEmpty()) { handoffCondition.wait(); } } } catch (InterruptedException e) { throw Throwables.propagate(e); } } // scheduledExecutor is shutdown here, but persistExecutor is shutdown when the // ServerView sends it a new segment callback if (scheduledExecutor != null) { scheduledExecutor.shutdown(); } stopped = true; } private void initializeExecutors() { if (persistExecutor == null) { persistExecutor = Executors.newFixedThreadPool(1, new ThreadFactoryBuilder().setDaemon(true).setNameFormat("plumber_persist_%d").build()); } if (scheduledExecutor == null) { scheduledExecutor = Executors.newScheduledThreadPool(1, new ThreadFactoryBuilder() .setDaemon(true).setNameFormat("plumber_scheduled_%d").build()); } } private void bootstrapSinksFromDisk() { for (File sinkDir : computeBaseDir(schema).listFiles()) { Interval sinkInterval = new Interval(sinkDir.getName().replace("_", "/")); //final File[] sinkFiles = sinkDir.listFiles(); // To avoid reading and listing of "merged" dir final File[] sinkFiles = sinkDir.listFiles(new FilenameFilter() { @Override public boolean accept(File dir, String fileName) { return !(Ints.tryParse(fileName) == null); } }); Arrays.sort(sinkFiles, new Comparator<File>() { @Override public int compare(File o1, File o2) { try { return Ints.compare(Integer.parseInt(o1.getName()), Integer.parseInt(o2.getName())); } catch (NumberFormatException e) { log.error(e, "Couldn't compare as numbers? [%s][%s]", o1, o2); return o1.compareTo(o2); } } }); try { List<FireHydrant> hydrants = Lists.newArrayList(); for (File segmentDir : sinkFiles) { log.info("Loading previously persisted segment at [%s]", segmentDir); // Although this has been tackled at start of this method. // Just a doubly-check added to skip "merged" dir. from being added to hydrants // If 100% sure that this is not needed, this check can be removed. if (Ints.tryParse(segmentDir.getName()) == null) { continue; } hydrants.add( new FireHydrant(new QueryableIndexSegment(null, IndexIO.loadIndex(segmentDir)), Integer.parseInt(segmentDir.getName()))); } Sink currSink = new Sink(sinkInterval, schema, versioningPolicy.getVersion(sinkInterval), hydrants); sinks.put(sinkInterval.getStartMillis(), currSink); sinkTimeline.add(currSink.getInterval(), currSink.getVersion(), new SingleElementPartitionChunk<Sink>(currSink)); segmentAnnouncer.announceSegment(currSink.getSegment()); } catch (IOException e) { log.makeAlert(e, "Problem loading sink[%s] from disk.", schema.getDataSource()) .addData("interval", sinkInterval).emit(); } } } private void registerServerViewCallback() { serverView.registerSegmentCallback(persistExecutor, new ServerView.BaseSegmentCallback() { @Override public ServerView.CallbackAction segmentAdded(DruidServer server, DataSegment segment) { if (stopped) { log.info("Unregistering ServerViewCallback"); persistExecutor.shutdown(); return ServerView.CallbackAction.UNREGISTER; } if ("realtime".equals(server.getType())) { return ServerView.CallbackAction.CONTINUE; } log.debug("Checking segment[%s] on server[%s]", segment, server); if (schema.getDataSource().equals(segment.getDataSource())) { final Interval interval = segment.getInterval(); for (Map.Entry<Long, Sink> entry : sinks.entrySet()) { final Long sinkKey = entry.getKey(); if (interval.contains(sinkKey)) { final Sink sink = entry.getValue(); log.info("Segment[%s] matches sink[%s] on server[%s]", segment, sink, server); final String segmentVersion = segment.getVersion(); final String sinkVersion = sink.getSegment().getVersion(); if (segmentVersion.compareTo(sinkVersion) >= 0) { log.info("Segment version[%s] >= sink version[%s]", segmentVersion, sinkVersion); try { segmentAnnouncer.unannounceSegment(sink.getSegment()); FileUtils .deleteDirectory(computePersistDir(schema, sink.getInterval())); log.info("Removing sinkKey %d for segment %s", sinkKey, sink.getSegment().getIdentifier()); sinks.remove(sinkKey); sinkTimeline.remove(sink.getInterval(), sink.getVersion(), new SingleElementPartitionChunk<Sink>(sink)); synchronized (handoffCondition) { handoffCondition.notifyAll(); } } catch (IOException e) { log.makeAlert(e, "Unable to delete old segment for dataSource[%s].", schema.getDataSource()).addData("interval", sink.getInterval()) .emit(); } } } } } return ServerView.CallbackAction.CONTINUE; } }); } private void startPersistThread() { final long truncatedNow = segmentGranularity.truncate(new DateTime()).getMillis(); final long windowMillis = windowPeriod.toStandardDuration().getMillis(); log.info("Expect to run at [%s]", new DateTime().plus(new Duration(System.currentTimeMillis(), segmentGranularity.increment(truncatedNow) + windowMillis))); ScheduledExecutors.scheduleAtFixedRate(scheduledExecutor, new Duration(System.currentTimeMillis(), segmentGranularity.increment(truncatedNow) + windowMillis), new Duration(truncatedNow, segmentGranularity.increment(truncatedNow)), new ThreadRenamingCallable<ScheduledExecutors.Signal>(String.format("%s-overseer-%d", schema.getDataSource(), schema.getShardSpec().getPartitionNum())) { @Override public ScheduledExecutors.Signal doCall() { if (stopped) { log.info("Stopping merge-n-push overseer thread"); return ScheduledExecutors.Signal.STOP; } log.info("Starting merge and push."); long minTimestamp = segmentGranularity .truncate(rejectionPolicy.getCurrMaxTime().minus(windowMillis)).getMillis(); List<Map.Entry<Long, Sink>> sinksToPush = Lists.newArrayList(); for (Map.Entry<Long, Sink> entry : sinks.entrySet()) { final Long intervalStart = entry.getKey(); if (intervalStart < minTimestamp) { log.info("Adding entry[%s] for merge and push.", entry); sinksToPush.add(entry); } } for (final Map.Entry<Long, Sink> entry : sinksToPush) { persistAndMerge(entry.getKey(), entry.getValue()); } if (stopped) { log.info("Stopping merge-n-push overseer thread"); return ScheduledExecutors.Signal.STOP; } else { return ScheduledExecutors.Signal.REPEAT; } } }); } }; } private File computeBaseDir(Schema schema) { return new File(basePersistDirectory, schema.getDataSource()); } private File computePersistDir(Schema schema, Interval interval) { return new File(computeBaseDir(schema), interval.toString().replace("/", "_")); } /** * Persists the given hydrant and returns the number of rows persisted * * @param indexToPersist * @param schema * @param interval * * @return the number of rows persisted */ private int persistHydrant(FireHydrant indexToPersist, Schema schema, Interval interval) { if (indexToPersist.hasSwapped()) { log.info("DataSource[%s], Interval[%s], Hydrant[%s] already swapped. Ignoring request to persist.", schema.getDataSource(), interval, indexToPersist); return 0; } log.info("DataSource[%s], Interval[%s], persisting Hydrant[%s]", schema.getDataSource(), interval, indexToPersist); try { int numRows = indexToPersist.getIndex().size(); File persistedFile = IndexMerger.persist(indexToPersist.getIndex(), new File(computePersistDir(schema, interval), String.valueOf(indexToPersist.getCount()))); indexToPersist.swapSegment(new QueryableIndexSegment(null, IndexIO.loadIndex(persistedFile))); return numRows; } catch (IOException e) { log.makeAlert("dataSource[%s] -- incremental persist failed", schema.getDataSource()) .addData("interval", interval).addData("count", indexToPersist.getCount()).emit(); throw Throwables.propagate(e); } } private void verifyState() { Preconditions.checkNotNull(conglomerate, "must specify a queryRunnerFactoryConglomerate to do this action."); Preconditions.checkNotNull(dataSegmentPusher, "must specify a segmentPusher to do this action."); Preconditions.checkNotNull(segmentAnnouncer, "must specify a segmentAnnouncer to do this action."); Preconditions.checkNotNull(segmentPublisher, "must specify a segmentPublisher to do this action."); Preconditions.checkNotNull(serverView, "must specify a serverView to do this action."); Preconditions.checkNotNull(emitter, "must specify a serviceEmitter to do this action."); } }