| /** |
| * 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.hadoop.hdfs.server.federation.router; |
| |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.apache.hadoop.service.AbstractService; |
| import org.apache.hadoop.service.ServiceStateException; |
| import org.apache.hadoop.util.Time; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.common.util.concurrent.ThreadFactoryBuilder; |
| |
| /** |
| * Service to periodically execute a runnable. |
| */ |
| public abstract class PeriodicService extends AbstractService { |
| |
| private static final Logger LOG = |
| LoggerFactory.getLogger(PeriodicService.class); |
| |
| /** Default interval in milliseconds for the periodic service. */ |
| private static final long DEFAULT_INTERVAL_MS = TimeUnit.MINUTES.toMillis(1); |
| |
| |
| /** Interval for running the periodic service in milliseconds. */ |
| private long intervalMs; |
| /** Name of the service. */ |
| private final String serviceName; |
| |
| /** Scheduler for the periodic service. */ |
| private final ScheduledExecutorService scheduler; |
| |
| /** If the service is running. */ |
| private volatile boolean isRunning = false; |
| |
| /** How many times we run. */ |
| private long runCount; |
| /** How many errors we got. */ |
| private long errorCount; |
| /** When was the last time we executed this service successfully. */ |
| private long lastRun; |
| |
| /** |
| * Create a new periodic update service. |
| * |
| * @param name Name of the service. |
| */ |
| public PeriodicService(String name) { |
| this(name, DEFAULT_INTERVAL_MS); |
| } |
| |
| /** |
| * Create a new periodic update service. |
| * |
| * @param name Name of the service. |
| * @param interval Interval for the periodic service in milliseconds. |
| */ |
| public PeriodicService(String name, long interval) { |
| super(name); |
| this.serviceName = name; |
| this.intervalMs = interval; |
| |
| ThreadFactory threadFactory = new ThreadFactoryBuilder() |
| .setNameFormat(this.getName() + "-%d") |
| .build(); |
| this.scheduler = Executors.newScheduledThreadPool(1, threadFactory); |
| } |
| |
| /** |
| * Set the interval for the periodic service. |
| * |
| * @param interval Interval in milliseconds. |
| */ |
| protected void setIntervalMs(long interval) { |
| if (getServiceState() == STATE.STARTED) { |
| throw new ServiceStateException("Periodic service already started"); |
| } else { |
| this.intervalMs = interval; |
| } |
| } |
| |
| /** |
| * Get the interval for the periodic service. |
| * |
| * @return Interval in milliseconds. |
| */ |
| protected long getIntervalMs() { |
| return this.intervalMs; |
| } |
| |
| /** |
| * Get how many times we failed to run the periodic service. |
| * |
| * @return Times we failed to run the periodic service. |
| */ |
| protected long getErrorCount() { |
| return this.errorCount; |
| } |
| |
| /** |
| * Get how many times we run the periodic service. |
| * |
| * @return Times we run the periodic service. |
| */ |
| protected long getRunCount() { |
| return this.runCount; |
| } |
| |
| /** |
| * Get the last time the periodic service was executed. |
| * |
| * @return Last time the periodic service was executed. |
| */ |
| protected long getLastUpdate() { |
| return this.lastRun; |
| } |
| |
| @Override |
| protected void serviceStart() throws Exception { |
| super.serviceStart(); |
| LOG.info("Starting periodic service {}", this.serviceName); |
| startPeriodic(); |
| } |
| |
| @Override |
| protected void serviceStop() throws Exception { |
| stopPeriodic(); |
| LOG.info("Stopping periodic service {}", this.serviceName); |
| super.serviceStop(); |
| } |
| |
| /** |
| * Stop the periodic task. |
| */ |
| protected synchronized void stopPeriodic() { |
| if (this.isRunning) { |
| LOG.info("{} is shutting down", this.serviceName); |
| this.isRunning = false; |
| this.scheduler.shutdownNow(); |
| } |
| } |
| |
| /** |
| * Start the periodic execution. |
| */ |
| protected synchronized void startPeriodic() { |
| stopPeriodic(); |
| |
| // Create the runnable service |
| Runnable updateRunnable = new Runnable() { |
| @Override |
| public void run() { |
| LOG.debug("Running {} update task", serviceName); |
| try { |
| if (!isRunning) { |
| return; |
| } |
| periodicInvoke(); |
| runCount++; |
| lastRun = Time.now(); |
| } catch (Exception ex) { |
| errorCount++; |
| LOG.warn(serviceName + " service threw an exception", ex); |
| } |
| } |
| }; |
| |
| // Start the execution of the periodic service |
| this.isRunning = true; |
| this.scheduler.scheduleWithFixedDelay( |
| updateRunnable, 0, this.intervalMs, TimeUnit.MILLISECONDS); |
| } |
| |
| /** |
| * Method that the service will run periodically. |
| */ |
| protected abstract void periodicInvoke(); |
| } |