org.apache.pulsar.broker.service.DistributedIdGenerator Maven / Gradle / Ivy
/**
* 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.
*
* 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.
*
* 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);
}