| /* |
| * 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.beam.runners.dataflow.worker.status; |
| |
| import java.io.IOException; |
| import java.io.PrintWriter; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Objects; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| import org.apache.beam.runners.dataflow.worker.status.DebugCapture.Capturable; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.annotations.VisibleForTesting; |
| |
| /** Respond to /threadz with the stack traces of all running threads. */ |
| class ThreadzServlet extends BaseStatusServlet implements Capturable { |
| |
| public ThreadzServlet() { |
| super("threadz"); |
| } |
| |
| /** |
| * Class representing the execution state of a thread. |
| * |
| * <p>Can be used in hash maps. |
| */ |
| @VisibleForTesting |
| static class Stack { |
| final StackTraceElement[] elements; |
| final Thread.State state; |
| |
| Stack(StackTraceElement[] elements, Thread.State state) { |
| this.elements = elements; |
| this.state = state; |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(Arrays.deepHashCode(elements), state); |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (other == this) { |
| return true; |
| } else if (!(other instanceof Stack)) { |
| return false; |
| } else { |
| Stack that = (Stack) other; |
| return state == that.state && Arrays.deepEquals(elements, that.elements); |
| } |
| } |
| } |
| |
| @VisibleForTesting |
| static Map<Stack, List<String>> deduplicateThreadStacks( |
| Map<Thread, StackTraceElement[]> allStacks) { |
| Map<Stack, List<String>> stacks = new HashMap<>(); |
| for (Map.Entry<Thread, StackTraceElement[]> entry : allStacks.entrySet()) { |
| Thread thread = entry.getKey(); |
| if (thread != Thread.currentThread()) { |
| Stack stack = new Stack(entry.getValue(), thread.getState()); |
| List<String> threads = stacks.get(stack); |
| if (threads == null) { |
| threads = new ArrayList<>(); |
| stacks.put(stack, threads); |
| } |
| threads.add(thread.toString()); |
| } |
| } |
| return stacks; |
| } |
| |
| @Override |
| public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException { |
| response.setContentType("text/plain;charset=utf-8"); |
| response.setStatus(HttpServletResponse.SC_OK); |
| captureData(response.getWriter()); |
| } |
| |
| @Override |
| public String pageName() { |
| return "/threadz"; |
| } |
| |
| @Override |
| public void captureData(PrintWriter writer) { |
| // First, build a map of stacks to the threads that have that stack. |
| Map<Stack, List<String>> stacks = deduplicateThreadStacks(Thread.getAllStackTraces()); |
| |
| // Then, print out each stack along with the threads that share it. Stacks with more threads |
| // are printed first. |
| stacks.entrySet().stream() |
| .sorted(Comparator.comparingInt(e -> -e.getValue().size())) |
| .forEachOrdered( |
| entry -> { |
| Stack stack = entry.getKey(); |
| List<String> threads = entry.getValue(); |
| writer.println( |
| "--- Threads (" |
| + threads.size() |
| + "): " |
| + threads |
| + " State: " |
| + stack.state |
| + " stack: ---"); |
| for (StackTraceElement element : stack.elements) { |
| writer.println(" " + element); |
| } |
| writer.println(); |
| }); |
| } |
| } |