| /* |
| * 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.samza.zk; |
| |
| import com.google.common.base.Preconditions; |
| import org.apache.samza.coordinator.ClusterMembership; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| public class ZkClusterMembership implements ClusterMembership { |
| |
| public static final Logger LOG = LoggerFactory.getLogger(ZkClusterMembership.class); |
| public static final String PROCESSORS_PATH = "processors"; |
| private final ZkUtils zkUtils; |
| private final String processorsPath; |
| private final String participantId; |
| private final ZkKeyBuilder keyBuilder; |
| |
| public ZkClusterMembership(String participantId, ZkUtils zkUtils) { |
| Preconditions.checkNotNull(participantId, "ParticipantId cannot be null"); |
| Preconditions.checkNotNull(zkUtils, "ZkUtils cannot be null"); |
| this.zkUtils = zkUtils; |
| this.participantId = participantId; |
| this.keyBuilder = zkUtils.getKeyBuilder(); |
| processorsPath = String.format("%s/%s", keyBuilder.getRootPath(), PROCESSORS_PATH); |
| zkUtils.validatePaths(new String[] {processorsPath}); |
| } |
| |
| @Override |
| public String registerProcessor() { |
| String nodePath = zkUtils.getZkClient().createEphemeralSequential(processorsPath + "/", participantId); |
| LOG.info("created ephemeral node. Registered the processor in the cluster."); |
| return ZkKeyBuilder.parseIdFromPath(nodePath); |
| } |
| |
| @Override |
| public int getNumberOfProcessors() { |
| return zkUtils.getZkClient().getChildren(processorsPath).size(); |
| } |
| |
| @Override |
| public void unregisterProcessor(String processorId) { |
| if (processorId == null) { |
| LOG.warn("Can not unregister processor with null processorId"); |
| return; |
| } |
| String nodePath = processorsPath + "/" + processorId; |
| if (zkUtils.exists(nodePath)) { |
| zkUtils.getZkClient().delete(nodePath); |
| LOG.info("Ephemeral node deleted. Unregistered the processor from cluster membership."); |
| } else { |
| LOG.warn("Ephemeral node you want to delete doesnt exist. Processor with id {} is not currently registered.", processorId); |
| } |
| } |
| } |