| /* |
| * 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.pulsar.broker.service; |
| |
| import java.util.concurrent.atomic.AtomicLong; |
| import org.apache.pulsar.metadata.api.coordination.CoordinationService; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Generate unique ids across multiple nodes. |
| * <p> |
| * Each node has an instance of this class and uses the same z-node. At startup each node gets assigned a unique id, |
| * using ZK sequential nodes. |
| * <p> |
| * After that, each node can just use a local counter and combine, the application prefix, its own instance id and with |
| * the counter incremental value to obtain a globally unique id. |
| */ |
| public class DistributedIdGenerator { |
| |
| private final String prefix; |
| private final long generatorInstanceId; |
| private final AtomicLong counter; |
| |
| /** |
| * |
| * @param cs |
| * {@link CoordinationService} |
| * @param path |
| * path of the z-node used to track the generators ids |
| * @param prefix |
| * prefix to prepend to the generated id. Having a unique prefix can make the id globally unique |
| * @throws Exception |
| */ |
| public DistributedIdGenerator(CoordinationService cs, String path, String prefix) throws Exception { |
| this.prefix = prefix; |
| this.counter = new AtomicLong(0); |
| this.generatorInstanceId = cs.getNextCounterValue(path).get(); |
| log.info("Broker distributed id generator started with instance id {}-{}", prefix, generatorInstanceId); |
| } |
| |
| public String getNextId() { |
| return String.format("%s-%d-%d", prefix, generatorInstanceId, counter.getAndIncrement()); |
| } |
| |
| private static final Logger log = LoggerFactory.getLogger(DistributedIdGenerator.class); |
| } |