abstractdog commented on code in PR #427: URL: https://github.com/apache/tez/pull/427#discussion_r2565261793
########## tez-dag/src/main/java/org/apache/tez/dag/api/client/registry/zookeeper/ZkAMRegistry.java: ########## @@ -0,0 +1,175 @@ +/** + * 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.dag.api.client.registry.zookeeper; + +import java.nio.charset.StandardCharsets; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; + +import org.apache.curator.RetryLoop; +import org.apache.curator.RetryPolicy; +import org.apache.curator.framework.CuratorFramework; +import org.apache.hadoop.classification.InterfaceAudience; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.registry.client.binding.RegistryUtils; +import org.apache.hadoop.yarn.api.records.ApplicationId; +import org.apache.tez.client.registry.AMRecord; +import org.apache.tez.client.registry.AMRegistry; +import org.apache.tez.client.registry.zookeeper.ZkConfig; +import org.apache.zookeeper.CreateMode; +import org.apache.zookeeper.KeeperException; +import org.apache.zookeeper.data.Stat; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Curator/Zookeeper impl of AMRegistry (for internal use only) + * Clients should use org.apache.tez.dag.api.client.registry.zookeeper.ZkAMRegistryClient instead. + */ [email protected] +public class ZkAMRegistry extends AMRegistry { + + private static final Logger LOG = LoggerFactory.getLogger(ZkAMRegistry.class); + + private final List<AMRecord> amRecords = new ArrayList<>(); + private final String externalId; + + private CuratorFramework client = null; + private String namespace = null; + private ZkConfig zkConfig = null; + private boolean started = false; + + public ZkAMRegistry(String externalId) { + super("ZkAMRegistry"); + this.externalId = externalId; + } + + @Override + public void serviceInit(Configuration conf) { + if (zkConfig == null) { + zkConfig = new ZkConfig(conf); + this.client = zkConfig.createCuratorFramework(); + this.namespace = zkConfig.getZkNamespace(); + LOG.info("AMRegistryZkImpl initialized"); + } + } + + @Override + public void serviceStart() throws Exception { + if (!started) { + client.start(); + started = true; + LOG.info("AMRegistryZkImpl started"); + } + } + + //Deletes from Zookeeper AMRecords that were added by this instance + @Override + public void serviceStop() throws Exception { + List<AMRecord> records = new ArrayList<>(amRecords); + for (AMRecord amRecord : records) { + remove(amRecord); + } + client.close(); + LOG.info("AMRegistryZkImpl shutdown"); + } + + //Serialize AMRecord to ServiceRecord and deliver the JSON bytes to + //zkNode at the path: <TEZ_AM_REGISTRY_NAMESPACE>/<appId> + @Override + public void add(AMRecord server) throws Exception { + RegistryUtils.ServiceRecordMarshal marshal = new RegistryUtils.ServiceRecordMarshal(); + String json = marshal.toJson(server.toServiceRecord()); + try { + final String path = namespace + "/" + server.getApplicationId().toString(); + client.setData().forPath(path, json.getBytes(StandardCharsets.UTF_8)); + LOG.info("Added AMRecord to zkpath {}", path); + } catch (KeeperException.NoNodeException nne) { + client.create().creatingParentContainersIfNeeded().withMode(CreateMode.EPHEMERAL) + .forPath(namespace + "/" + server.getApplicationId().toString(), json.getBytes(StandardCharsets.UTF_8)); + } + amRecords.add(server); + } + + @Override + public void remove(AMRecord server) throws Exception { + amRecords.remove(server); + final String path = namespace + "/" + server.getApplicationId().toString(); + client.delete().forPath(path); + LOG.info("Deleted AMRecord from zkpath {}", path); + } + + @Override + public ApplicationId generateNewId() throws Exception { + createNamespaceIfNotExists(); + long namespaceCreationTime = getNamespaceCreationTime(); + + boolean success = false; + long startTime = System.currentTimeMillis(); + RetryPolicy retryPolicy = zkConfig.getRetryPolicy(); + int tryId = 0; + for (int i = 0; (i < zkConfig.getCuratorMaxRetries()) && !success; i++) { + List<String> children = client.getChildren().forPath(namespace); + if (children != null && !children.isEmpty()) { + children.sort(Collections.reverseOrder()); + String last = children.getFirst(); + ApplicationId lastAppId = ApplicationId.fromString(last); + tryId = lastAppId.getId() + 1; Review Comment: thread safety is indeed concerning, I was able to reproduce the problem with a unit test case -- This is an automated message from the Apache Git Service. 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