/*
 * Copyright (c) 2014 Red Hat, Inc. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 * which is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 */

package io.vertx.core.impl;

import io.vertx.core.VertxException;
import io.vertx.core.logging.Logger;
import io.vertx.core.logging.LoggerFactory;

import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;
import java.util.WeakHashMap;
import java.util.concurrent.TimeUnit;

Author:Tim Fox
/** * @author <a href="http://tfox.org">Tim Fox</a> */
public class BlockedThreadChecker {
A checked task.
/** * A checked task. */
public interface Task { long startTime(); long maxExecTime(); TimeUnit maxExecTimeUnit(); } private static final Logger log = LoggerFactory.getLogger(BlockedThreadChecker.class); private final Map<Thread, Task> threads = new WeakHashMap<>(); private final Timer timer; // Need to use our own timer - can't use event loop for this BlockedThreadChecker(long interval, TimeUnit intervalUnit, long warningExceptionTime, TimeUnit warningExceptionTimeUnit) { timer = new Timer("vertx-blocked-thread-checker", true); timer.schedule(new TimerTask() { @Override public void run() { synchronized (BlockedThreadChecker.this) { long now = System.nanoTime(); for (Map.Entry<Thread, Task> entry : threads.entrySet()) { long execStart = entry.getValue().startTime(); long dur = now - execStart; final long timeLimit = entry.getValue().maxExecTime(); TimeUnit maxExecTimeUnit = entry.getValue().maxExecTimeUnit(); long val = maxExecTimeUnit.convert(dur, TimeUnit.NANOSECONDS); if (execStart != 0 && val >= timeLimit) { final String message = "Thread " + entry + " has been blocked for " + (dur / 1_000_000) + " ms, time limit is " + TimeUnit.MILLISECONDS.convert(timeLimit, maxExecTimeUnit) + " ms"; if (warningExceptionTimeUnit.convert(dur, TimeUnit.NANOSECONDS) <= warningExceptionTime) { log.warn(message); } else { VertxException stackTrace = new VertxException("Thread blocked"); stackTrace.setStackTrace(entry.getKey().getStackTrace()); log.warn(message, stackTrace); } } } } } }, intervalUnit.toMillis(interval), intervalUnit.toMillis(interval)); } public synchronized void registerThread(Thread thread, Task checked) { threads.put(thread, checked); } public void close() { timer.cancel(); } }