jihoonson commented on a change in pull request #6901: Introduce published segment cache in broker URL: https://github.com/apache/incubator-druid/pull/6901#discussion_r252509856
########## File path: server/src/main/java/org/apache/druid/client/MetadataSegmentView.java ########## @@ -0,0 +1,200 @@ +/* + * 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 org.apache.druid.client; + +import com.fasterxml.jackson.core.type.TypeReference; +import com.fasterxml.jackson.databind.JavaType; +import com.fasterxml.jackson.databind.ObjectMapper; +import com.google.common.util.concurrent.ListenableFuture; +import com.google.inject.Inject; +import org.apache.druid.client.coordinator.Coordinator; +import org.apache.druid.discovery.DruidLeaderClient; +import org.apache.druid.guice.ManageLifecycle; +import org.apache.druid.java.util.common.DateTimes; +import org.apache.druid.java.util.common.StringUtils; +import org.apache.druid.java.util.common.concurrent.Execs; +import org.apache.druid.java.util.common.lifecycle.LifecycleStart; +import org.apache.druid.java.util.common.lifecycle.LifecycleStop; +import org.apache.druid.java.util.common.logger.Logger; +import org.apache.druid.java.util.http.client.Request; +import org.apache.druid.server.coordinator.BytesAccumulatingResponseHandler; +import org.apache.druid.timeline.DataSegment; +import org.jboss.netty.handler.codec.http.HttpMethod; +import org.joda.time.DateTime; + +import java.io.IOException; +import java.io.InputStream; +import java.util.Iterator; +import java.util.Set; +import java.util.concurrent.Callable; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentMap; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.stream.Collectors; + +/** + * This class polls the coordinator in background to keep the latest published segments. + * Provides {@link #getPublishedSegments()} for others to get segments in metadata store. + */ +@ManageLifecycle +public class MetadataSegmentView +{ + + private static final int DEFAULT_POLL_PERIOD_IN_MS = 60000; + private static final Logger log = new Logger(MetadataSegmentView.class); + + private final DruidLeaderClient coordinatorDruidLeaderClient; + private final ObjectMapper jsonMapper; + private final BytesAccumulatingResponseHandler responseHandler; + private final BrokerSegmentWatcherConfig segmentWatcherConfig; + + private final ConcurrentMap<DataSegment, DateTime> publishedSegments = new ConcurrentHashMap<>(); + private ScheduledExecutorService scheduledExec; + + @Inject + public MetadataSegmentView( + final @Coordinator DruidLeaderClient druidLeaderClient, + final ObjectMapper jsonMapper, + final BytesAccumulatingResponseHandler responseHandler, + final BrokerSegmentWatcherConfig segmentWatcherConfig + ) + { + this.coordinatorDruidLeaderClient = druidLeaderClient; + this.jsonMapper = jsonMapper; + this.responseHandler = responseHandler; + this.segmentWatcherConfig = segmentWatcherConfig; + } + + @LifecycleStart + public void start() + { + scheduledExec = Execs.scheduledSingleThreaded("MetadataSegmentView-Cache--%d"); + scheduledExec.schedule(new PollTask(), 0, TimeUnit.MILLISECONDS); + } + + @LifecycleStop + public void stop() + { + scheduledExec.shutdownNow(); + scheduledExec = null; + } + + private void poll() + { + log.info("polling published segments from coordinator"); + //get authorized published segments from coordinator + final JsonParserIterator<DataSegment> metadataSegments = getMetadataSegments( + coordinatorDruidLeaderClient, + jsonMapper, + responseHandler, + segmentWatcherConfig.getWatchedDataSources() + ); + + final DateTime timestamp = DateTimes.nowUtc(); + while (metadataSegments.hasNext()) { + final DataSegment interned = DataSegmentInterner.intern(metadataSegments.next()); + // timestamp is used to filter deleted segments + publishedSegments.put(interned, timestamp); + } + // filter the segments from cache whose timestamp is not equal to latest timestamp stored, + // since the presence of a segment with an earlier timestamp indicates that + // "that" segment is not returned by coordinator in latest poll, so it's + // likely deleted and therefore we remove it from publishedSegments + final Set<DateTime> toBeRemovedSegments = publishedSegments.values() + .stream() + .filter(v -> v != timestamp) + .collect(Collectors.toSet()); + publishedSegments.values().removeAll(toBeRemovedSegments); + + if (segmentWatcherConfig.getWatchedDataSources() != null) { + log.debug( + "filtering datasources[%s] in published segments based on broker's watchedDataSources", + segmentWatcherConfig.getWatchedDataSources() + ); + publishedSegments.keySet() + .removeIf(key -> !segmentWatcherConfig.getWatchedDataSources().contains(key.getDataSource())); + } + } + + public Iterator<DataSegment> getPublishedSegments() + { + return publishedSegments.keySet().iterator(); + } + + // Note that coordinator must be up to get segments + private static JsonParserIterator<DataSegment> getMetadataSegments( + DruidLeaderClient coordinatorClient, + ObjectMapper jsonMapper, + BytesAccumulatingResponseHandler responseHandler, + Set<String> watchedDataSources + ) + { + String query = "/druid/coordinator/v1/metadata/segments"; + if (watchedDataSources != null && !watchedDataSources.isEmpty()) { + final StringBuilder sb = new StringBuilder(); + for (String ds : watchedDataSources) { + sb.append("datasources=" + ds + "&"); Review comment: Ok. Please check https://github.com/apache/incubator-druid/pull/6901/files#r252479790. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org
