| /** |
| * 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.util; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Facilitates hooking process termination for tests, debugging |
| * and embedding. |
| * |
| * Hadoop code that attempts to call {@link System#exit(int)} |
| * or {@link Runtime#halt(int)} MUST invoke it via these methods. |
| */ |
| @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce", "YARN"}) |
| @InterfaceStability.Unstable |
| public final class ExitUtil { |
| private static final Logger |
| LOG = LoggerFactory.getLogger(ExitUtil.class.getName()); |
| private static volatile boolean systemExitDisabled = false; |
| private static volatile boolean systemHaltDisabled = false; |
| private static volatile ExitException firstExitException; |
| private static volatile HaltException firstHaltException; |
| /** Message raised from an exit exception if none were provided: {@value}. */ |
| public static final String EXIT_EXCEPTION_MESSAGE = "ExitException"; |
| /** Message raised from a halt exception if none were provided: {@value}. */ |
| public static final String HALT_EXCEPTION_MESSAGE = "HaltException"; |
| |
| private ExitUtil() { |
| } |
| |
| /** |
| * An exception raised when a call to {@link #terminate(int)} was |
| * called and system exits were blocked. |
| */ |
| public static class ExitException extends RuntimeException |
| implements ExitCodeProvider { |
| private static final long serialVersionUID = 1L; |
| /** |
| * The status code. |
| */ |
| public final int status; |
| |
| public ExitException(int status, String msg) { |
| super(msg); |
| this.status = status; |
| } |
| |
| public ExitException(int status, |
| String message, |
| Throwable cause) { |
| super(message, cause); |
| this.status = status; |
| } |
| |
| public ExitException(int status, Throwable cause) { |
| super(cause); |
| this.status = status; |
| } |
| |
| @Override |
| public int getExitCode() { |
| return status; |
| } |
| |
| /** |
| * String value does not include exception type, just exit code and message. |
| * @return the exit code and any message |
| */ |
| @Override |
| public String toString() { |
| String message = getMessage(); |
| if (message == null) { |
| message = super.toString(); |
| } |
| return Integer.toString(status) + ": " + message; |
| } |
| } |
| |
| /** |
| * An exception raised when a call to {@link #terminate(int)} was |
| * called and system halts were blocked. |
| */ |
| public static class HaltException extends RuntimeException |
| implements ExitCodeProvider { |
| private static final long serialVersionUID = 1L; |
| public final int status; |
| |
| public HaltException(int status, Throwable cause) { |
| super(cause); |
| this.status = status; |
| } |
| |
| public HaltException(int status, String msg) { |
| super(msg); |
| this.status = status; |
| } |
| |
| public HaltException(int status, |
| String message, |
| Throwable cause) { |
| super(message, cause); |
| this.status = status; |
| } |
| |
| @Override |
| public int getExitCode() { |
| return status; |
| } |
| |
| /** |
| * String value does not include exception type, just exit code and message. |
| * @return the exit code and any message |
| */ |
| @Override |
| public String toString() { |
| String message = getMessage(); |
| if (message == null) { |
| message = super.toString(); |
| } |
| return Integer.toString(status) + ": " + message; |
| } |
| |
| } |
| |
| /** |
| * Disable the use of System.exit for testing. |
| */ |
| public static void disableSystemExit() { |
| systemExitDisabled = true; |
| } |
| |
| /** |
| * Disable the use of {@code Runtime.getRuntime().halt() } for testing. |
| */ |
| public static void disableSystemHalt() { |
| systemHaltDisabled = true; |
| } |
| |
| /** |
| * @return true if terminate has been called. |
| */ |
| public static boolean terminateCalled() { |
| // Either we set this member or we actually called System#exit |
| return firstExitException != null; |
| } |
| |
| /** |
| * @return true if halt has been called. |
| */ |
| public static boolean haltCalled() { |
| return firstHaltException != null; |
| } |
| |
| /** |
| * @return the first ExitException thrown, null if none thrown yet. |
| */ |
| public static ExitException getFirstExitException() { |
| return firstExitException; |
| } |
| |
| /** |
| * @return the first {@code HaltException} thrown, null if none thrown yet. |
| */ |
| public static HaltException getFirstHaltException() { |
| return firstHaltException; |
| } |
| |
| /** |
| * Reset the tracking of process termination. This is for use in unit tests |
| * where one test in the suite expects an exit but others do not. |
| */ |
| public static void resetFirstExitException() { |
| firstExitException = null; |
| } |
| |
| public static void resetFirstHaltException() { |
| firstHaltException = null; |
| } |
| |
| /** |
| * Inner termination: either exit with the exception's exit code, |
| * or, if system exits are disabled, rethrow the exception. |
| * @param ee exit exception |
| */ |
| public static synchronized void terminate(ExitException ee) |
| throws ExitException { |
| int status = ee.getExitCode(); |
| String msg = ee.getMessage(); |
| if (status != 0) { |
| //exit indicates a problem, log it |
| LOG.debug("Exiting with status {}: {}", status, msg, ee); |
| LOG.info("Exiting with status {}: {}", status, msg); |
| } |
| if (systemExitDisabled) { |
| LOG.error("Terminate called", ee); |
| if (!terminateCalled()) { |
| firstExitException = ee; |
| } |
| throw ee; |
| } |
| System.exit(status); |
| } |
| |
| /** |
| * Forcibly terminates the currently running Java virtual machine. |
| * The exception argument is rethrown if JVM halting is disabled. |
| * @param ee the exception containing the status code, message and any stack |
| * trace. |
| * @throws HaltException if {@link Runtime#halt(int)} is disabled. |
| */ |
| public static synchronized void halt(HaltException ee) throws HaltException { |
| int status = ee.getExitCode(); |
| String msg = ee.getMessage(); |
| try { |
| if (status != 0) { |
| //exit indicates a problem, log it |
| LOG.debug("Halt with status {}: {}", status, msg, ee); |
| LOG.info("Halt with status {}: {}", status, msg, msg); |
| } |
| } catch (Exception ignored) { |
| // ignore exceptions here, as it may be due to an out of memory situation |
| } |
| if (systemHaltDisabled) { |
| LOG.error("Halt called", ee); |
| if (!haltCalled()) { |
| firstHaltException = ee; |
| } |
| throw ee; |
| } |
| Runtime.getRuntime().halt(status); |
| } |
| |
| /** |
| * Like {@link #terminate(int, String)} but uses the given throwable to |
| * build the message to display or throw as an |
| * {@link ExitException}. |
| * <p> |
| * @param status exit code to use if the exception is not an ExitException. |
| * @param t throwable which triggered the termination. If this exception |
| * is an {@link ExitException} its status overrides that passed in. |
| * @throws ExitException if {@link System#exit(int)} is disabled. |
| */ |
| public static void terminate(int status, Throwable t) throws ExitException { |
| if (t instanceof ExitException) { |
| terminate((ExitException) t); |
| } else { |
| terminate(new ExitException(status, t)); |
| } |
| } |
| |
| /** |
| * Forcibly terminates the currently running Java virtual machine. |
| * |
| * @param status exit code to use if the exception is not a HaltException. |
| * @param t throwable which triggered the termination. If this exception |
| * is a {@link HaltException} its status overrides that passed in. |
| * @throws HaltException if {@link System#exit(int)} is disabled. |
| */ |
| public static void halt(int status, Throwable t) throws HaltException { |
| if (t instanceof HaltException) { |
| halt((HaltException) t); |
| } else { |
| halt(new HaltException(status, t)); |
| } |
| } |
| |
| /** |
| * Like {@link #terminate(int, Throwable)} without a message. |
| * |
| * @param status exit code |
| * @throws ExitException if {@link System#exit(int)} is disabled. |
| */ |
| public static void terminate(int status) throws ExitException { |
| terminate(status, EXIT_EXCEPTION_MESSAGE); |
| } |
| |
| /** |
| * Terminate the current process. Note that terminate is the *only* method |
| * that should be used to terminate the daemon processes. |
| * |
| * @param status exit code |
| * @param msg message used to create the {@code ExitException} |
| * @throws ExitException if {@link System#exit(int)} is disabled. |
| */ |
| public static void terminate(int status, String msg) throws ExitException { |
| terminate(new ExitException(status, msg)); |
| } |
| |
| /** |
| * Forcibly terminates the currently running Java virtual machine. |
| * @param status status code |
| * @throws HaltException if {@link Runtime#halt(int)} is disabled. |
| */ |
| public static void halt(int status) throws HaltException { |
| halt(status, HALT_EXCEPTION_MESSAGE); |
| } |
| |
| /** |
| * Forcibly terminates the currently running Java virtual machine. |
| * @param status status code |
| * @param message message |
| * @throws HaltException if {@link Runtime#halt(int)} is disabled. |
| */ |
| public static void halt(int status, String message) throws HaltException { |
| halt(new HaltException(status, message)); |
| } |
| |
| /** |
| * Handler for out of memory events -no attempt is made here |
| * to cleanly shutdown or support halt blocking; a robust |
| * printing of the event to stderr is all that can be done. |
| * @param oome out of memory event |
| */ |
| public static void haltOnOutOfMemory(OutOfMemoryError oome) { |
| //After catching an OOM java says it is undefined behavior, so don't |
| //even try to clean up or we can get stuck on shutdown. |
| try { |
| System.err.println("Halting due to Out Of Memory Error..."); |
| } catch (Throwable err) { |
| //Again we done want to exit because of logging issues. |
| } |
| Runtime.getRuntime().halt(-1); |
| } |
| } |