abstractdog commented on code in PR #427: URL: https://github.com/apache/tez/pull/427#discussion_r2549826279
########## tez-api/src/main/java/org/apache/tez/client/registry/zookeeper/ZkAMRegistryClient.java: ########## @@ -0,0 +1,205 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.tez.client.registry.zookeeper; + +import java.io.IOException; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; +import java.util.stream.Collectors; + +import org.apache.curator.framework.CuratorFramework; +import org.apache.curator.framework.imps.CuratorFrameworkState; +import org.apache.curator.framework.recipes.cache.ChildData; +import org.apache.curator.framework.recipes.cache.TreeCache; +import org.apache.curator.framework.recipes.cache.TreeCacheEvent; +import org.apache.curator.framework.recipes.cache.TreeCacheListener; +import org.apache.curator.shaded.com.google.common.base.Charsets; +import org.apache.hadoop.classification.InterfaceAudience; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.registry.client.binding.RegistryUtils; +import org.apache.hadoop.registry.client.types.ServiceRecord; +import org.apache.hadoop.yarn.api.records.ApplicationId; +import org.apache.tez.client.registry.AMRecord; +import org.apache.tez.client.registry.AMRegistryClient; +import org.apache.tez.client.registry.AMRegistryClientListener; +import org.apache.tez.dag.api.TezConfiguration; + +import com.fasterxml.jackson.core.JsonParseException; +import com.google.common.base.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Curator/Zookeeper implementation of {@link AMRegistryClient}. + */ [email protected] +public final class ZkAMRegistryClient extends AMRegistryClient { + private static final Logger LOG = LoggerFactory.getLogger(ZkAMRegistryClient.class); + private static final Map<String, ZkAMRegistryClient> INSTANCES = new HashMap<>(); + + private final Configuration conf; + //Cache of known AMs + private final ConcurrentHashMap<String, AMRecord> amRecordCache = new ConcurrentHashMap<>(); + private CuratorFramework client; + + private ZkAMRegistryClient(final Configuration conf) { + this.conf = conf; + } + + public static synchronized ZkAMRegistryClient getClient(final Configuration conf) { + String namespace = conf.get(TezConfiguration.TEZ_AM_REGISTRY_NAMESPACE); + ZkAMRegistryClient registry = INSTANCES.get(namespace); + if (registry == null) { + registry = new ZkAMRegistryClient(conf); + INSTANCES.put(namespace, registry); + } + LOG.info("Returning tez AM registry ({}) for namespace '{}'", System.identityHashCode(registry), namespace); + return registry; + } + + /** + * Deserializes a {@link ServiceRecord} from ZooKeeper data and converts it into an {@link AMRecord} + * for caching. + * + * @param childData the ZooKeeper node data containing a serialized {@link ServiceRecord} + * @return an {@link AMRecord} constructed from the deserialized {@link ServiceRecord}, or {@code null} + * if no data is present + * @throws IOException if the data cannot be deserialized into a {@link ServiceRecord} + */ + public static AMRecord getAMRecord(final ChildData childData) throws IOException { + // not a leaf path. Only leaf path contains AMRecord + if (!childData.getPath().contains(ApplicationId.appIdStrPrefix)) { + return null; + } + byte[] data = childData.getData(); + // only the path appeared, there is no data yet + if (data.length == 0) { + return null; + } + String value = new String(data, Charsets.UTF_8); + try { + RegistryUtils.ServiceRecordMarshal marshal = new RegistryUtils.ServiceRecordMarshal(); + ServiceRecord serviceRecord = marshal.fromJson(value); + return new AMRecord(serviceRecord); + } catch (JsonParseException e) { + //Not a json AMRecord (SRV), could be some other data. + LOG.warn("Non-json data received while de-serializing AMRecord: {}. Ignoring...", value); + return null; + } + } + + public void start() throws Exception { + ZkConfig zkConf = new ZkConfig(this.conf); + client = zkConf.createCuratorFramework(); + final TreeCache cache = new TreeCache(client, zkConf.getZkNamespace()); + client.start(); + cache.start(); + cache.getListenable().addListener(new ZkRegistryListener()); + } + + @Override + public AMRecord getRecord(String appId) { + if (amRecordCache.get(appId) == null) { + return null; + } + //Return a copy + return new AMRecord(amRecordCache.get(appId)); + } + + @Override + public List<AMRecord> getAllRecords() { + return amRecordCache.values().stream().map(AMRecord::new).collect(Collectors.toList()); + } + + @Override + public synchronized void addListener(AMRegistryClientListener listener) { + getListeners().add(listener); + } + + @Override + public void close() { + client.close(); + } + + /** + * Callback listener for ZooKeeper events that updates the local cache + * when child nodes under the monitored path change. + */ + private class ZkRegistryListener implements TreeCacheListener { + + @Override + public void childEvent(final CuratorFramework clientParam, final TreeCacheEvent event) throws Exception { + Preconditions.checkArgument(clientParam != null && clientParam.getState() == CuratorFrameworkState.STARTED, + "Curator client is not started"); + + ChildData childData = event.getData(); + switch (event.getType()) { + case NODE_ADDED: + if (isEmpty(childData)) { + LOG.info("AppId allocated: {}", childData.getPath()); + } else { + AMRecord amRecord = getAMRecord(childData); + if (amRecord != null) { + LOG.info("AM registered with data: {}. Notifying {} listeners.", amRecord, getListeners().size()); + amRecordCache.put(amRecord.getApplicationId().toString(), amRecord); + notifyOnAdded(amRecord); + } + } + break; + case NODE_UPDATED: + if (isEmpty(childData)) { + throw new RuntimeException("AM updated with empty data"); + } else { + AMRecord amRecord = getAMRecord(childData); + if (amRecord != null) { + LOG.info("AM updated data: {}. Notifying {} listeners.", amRecord, getListeners().size()); + amRecordCache.put(amRecord.getApplicationId().toString(), amRecord); + notifyOnAdded(amRecord); + } + } + break; + case NODE_REMOVED: + if (isEmpty(childData)) { + LOG.info("Unused AppId unregistered: {}", childData.getPath()); + } else { + AMRecord amRecord = getAMRecord(childData); + if (amRecord != null) { + LOG.info("AM removed: {}. Notifying {} listeners.", amRecord, getListeners().size()); + amRecordCache.remove(amRecord.getApplicationId().toString(), amRecord); Review Comment: refactored amRecordCache collection key to ApplicationId according to other comments I'm adding a unit test to double check correct AMRecord equals and hashCode behavior: if they both work properly, no matter the actual AMRecord instance, event removal should work properly -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
