Java tutorial
/* * Copyright 2016 Red Hat, Inc. * * Red Hat 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.arquillian.cube.kubernetes.impl.utils; import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.URL; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; import java.util.Map; import java.util.function.Function; import org.apache.commons.io.FileUtils; import org.arquillian.cube.impl.util.Strings; import org.arquillian.cube.kubernetes.api.Logger; /** * A helper class for running external processes * <p> * This class is a cut down version taken from the [Fabric8 Maven Plugin](https://github.com/fabric8io/fabric8-maven-plugin/blob/master/core/src/main/java/io/fabric8/maven/core/util/ProcessUtil.java) */ public class ProcessUtil { public static int runCommand(final Logger log, URL scriptUrl) throws IOException { return runCommand(log, scriptUrl, Collections.emptyMap()); } public static int runCommand(final Logger log, URL scriptUrl, Map<String, String> env) throws IOException { File scriptFile = File.createTempFile("arquillian-cube-script", getSuffix()); FileUtils.copyURLToFile(scriptUrl, scriptFile); scriptFile.setExecutable(true, false); return runCommand(log, getCommand(), Arrays.asList(new String[] { scriptFile.getAbsolutePath() }), env, true); } public static int runCommand(final Logger log, String command, List<String> args, Map<String, String> env, boolean withShutdownHook) throws IOException { String[] commandWithArgs = prepareCommandArray(command, args); String[] envp = prepareEnvp(env); Process process = Runtime.getRuntime().exec(commandWithArgs, envp); if (withShutdownHook) { addShutdownHook(log, process, command); } List<Thread> threads = startLoggingThreads(process, log, command + " " + Strings.join(args, " ")); try { int answer = process.waitFor(); joinThreads(threads, log); return answer; } catch (InterruptedException e) { return process.exitValue(); } } private static void joinThreads(List<Thread> threads, Logger log) { for (Thread thread : threads) { try { thread.join(); } catch (InterruptedException e) { log.warn("Caught " + e.getMessage()); } } } // ========================================================================================================== private static void addShutdownHook(final Logger log, final Process process, final String command) { Runtime.getRuntime().addShutdownHook(new Thread(command) { @Override public void run() { if (process != null) { log.info("Terminating process [" + command + "]"); try { process.destroy(); } catch (Exception e) { log.error("Failed to terminate process [" + command + "]"); } } } }); } private static String[] prepareCommandArray(String command, List<String> args) { List<String> nCmd = Strings.splitAndTrimAsList(command, " "); List<String> nArgs = args != null ? args : new ArrayList<String>(); String[] commandWithArgs = new String[nCmd.size() + nArgs.size()]; for (int i = 0; i < nCmd.size(); i++) { commandWithArgs[i] = nCmd.get(i); } for (int i = 0; i < nArgs.size(); i++) { commandWithArgs[i + nCmd.size()] = nArgs.get(i); } return commandWithArgs; } private static String[] prepareEnvp(Map<String, String> env) { ; String[] envp = new String[env.size()]; int i = 0; for (Map.Entry<String, String> entry : env.entrySet()) { envp[i++] = entry.getKey() + "=" + entry.getValue(); } return envp; } private static void processOutput(InputStream inputStream, Function<String, Void> function) throws IOException { try (BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) { String line = null; while ((line = reader.readLine()) != null) { function.apply(line); } } } private static List<Thread> startLoggingThreads(final Process process, final Logger log, final String commandDesc) { List<Thread> threads = new ArrayList<>(); threads.add(startOutputLoggingThread(process, log, commandDesc)); threads.add(startErrorLoggingThread(process, log, commandDesc)); return threads; } private static Thread startErrorLoggingThread(final Process process, final Logger log, final String commandDesc) { Thread logThread = new Thread("[ERR] " + commandDesc) { @Override public void run() { try { processOutput(process.getErrorStream(), createErrorHandler(log)); } catch (IOException e) { log.error("Failed to read error stream from [" + commandDesc + "] : [" + e.getMessage() + "]"); } } }; logThread.setDaemon(true); logThread.start(); return logThread; } private static Thread startOutputLoggingThread(final Process process, final Logger log, final String commandDesc) { Thread logThread = new Thread("[OUT] " + commandDesc) { @Override public void run() { try { processOutput(process.getInputStream(), createOutputHandler(log)); } catch (IOException e) { log.error("Failed to read output stream from [" + commandDesc + "] : [" + e.getMessage() + "]"); } } }; logThread.setDaemon(true); logThread.start(); return logThread; } private static Function<String, Void> createOutputHandler(final Logger log) { return new Function<String, Void>() { @Override public Void apply(String outputLine) { log.info(outputLine); return null; } }; } private static Function<String, Void> createErrorHandler(final Logger log) { return new Function<String, Void>() { @Override public Void apply(String outputLine) { log.error(outputLine); return null; } }; } public static boolean isWindows() { return System.getProperty("os.name").toLowerCase().contains("windows"); } private static final String getCommand() { if (isWindows()) { return "cmd /c start"; } else { return "/bin/sh -c"; } } private static final String getSuffix() { if (isWindows()) { return ".bat"; } else { return ".sh"; } } }