Java tutorial
/* * 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.zeppelin.interpreter.remote; import org.apache.commons.exec.*; import org.apache.commons.exec.environment.EnvironmentUtils; import org.apache.zeppelin.helium.ApplicationEventListener; import org.apache.zeppelin.interpreter.InterpreterException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.OutputStream; import java.util.Map; /** * This class manages start / stop of remote interpreter process */ public class RemoteInterpreterManagedProcess extends RemoteInterpreterProcess implements ExecuteResultHandler { private static final Logger logger = LoggerFactory.getLogger(RemoteInterpreterManagedProcess.class); private final String interpreterRunner; private DefaultExecutor executor; private ExecuteWatchdog watchdog; boolean running = false; private int port = -1; private final String interpreterDir; private final String localRepoDir; private Map<String, String> env; public RemoteInterpreterManagedProcess(String intpRunner, String intpDir, String localRepoDir, Map<String, String> env, int connectTimeout, RemoteInterpreterProcessListener listener, ApplicationEventListener appListener) { super(new RemoteInterpreterEventPoller(listener, appListener), connectTimeout); this.interpreterRunner = intpRunner; this.env = env; this.interpreterDir = intpDir; this.localRepoDir = localRepoDir; } RemoteInterpreterManagedProcess(String intpRunner, String intpDir, String localRepoDir, Map<String, String> env, RemoteInterpreterEventPoller remoteInterpreterEventPoller, int connectTimeout) { super(remoteInterpreterEventPoller, connectTimeout); this.interpreterRunner = intpRunner; this.env = env; this.interpreterDir = intpDir; this.localRepoDir = localRepoDir; } @Override public String getHost() { return "localhost"; } @Override public int getPort() { return port; } @Override public void start(String userName, Boolean isUserImpersonate) { // start server process try { port = RemoteInterpreterUtils.findRandomAvailablePortOnAllLocalInterfaces(); } catch (IOException e1) { throw new InterpreterException(e1); } CommandLine cmdLine = CommandLine.parse(interpreterRunner); cmdLine.addArgument("-d", false); cmdLine.addArgument(interpreterDir, false); cmdLine.addArgument("-p", false); cmdLine.addArgument(Integer.toString(port), false); if (isUserImpersonate && !userName.equals("anonymous")) { cmdLine.addArgument("-u", false); cmdLine.addArgument(userName, false); } cmdLine.addArgument("-l", false); cmdLine.addArgument(localRepoDir, false); executor = new DefaultExecutor(); ByteArrayOutputStream cmdOut = new ByteArrayOutputStream(); ProcessLogOutputStream processOutput = new ProcessLogOutputStream(logger); processOutput.setOutputStream(cmdOut); executor.setStreamHandler(new PumpStreamHandler(processOutput)); watchdog = new ExecuteWatchdog(ExecuteWatchdog.INFINITE_TIMEOUT); executor.setWatchdog(watchdog); try { Map procEnv = EnvironmentUtils.getProcEnvironment(); procEnv.putAll(env); logger.info("Run interpreter process {}", cmdLine); executor.execute(cmdLine, procEnv, this); running = true; } catch (IOException e) { running = false; throw new InterpreterException(e); } long startTime = System.currentTimeMillis(); while (System.currentTimeMillis() - startTime < getConnectTimeout()) { if (!running) { try { cmdOut.flush(); } catch (IOException e) { // nothing to do } throw new InterpreterException(new String(cmdOut.toByteArray())); } try { if (RemoteInterpreterUtils.checkIfRemoteEndpointAccessible("localhost", port)) { break; } else { try { Thread.sleep(500); } catch (InterruptedException e) { logger.error("Exception in RemoteInterpreterProcess while synchronized reference " + "Thread.sleep", e); } } } catch (Exception e) { if (logger.isDebugEnabled()) { logger.debug("Remote interpreter not yet accessible at localhost:" + port); } } } processOutput.setOutputStream(null); } public void stop() { if (isRunning()) { logger.info("kill interpreter process"); watchdog.destroyProcess(); } executor = null; watchdog = null; running = false; logger.info("Remote process terminated"); } @Override public void onProcessComplete(int exitValue) { logger.info("Interpreter process exited {}", exitValue); running = false; } @Override public void onProcessFailed(ExecuteException e) { logger.info("Interpreter process failed {}", e); running = false; } public boolean isRunning() { return running; } private static class ProcessLogOutputStream extends LogOutputStream { private Logger logger; OutputStream out; public ProcessLogOutputStream(Logger logger) { this.logger = logger; } @Override protected void processLine(String s, int i) { this.logger.debug(s); } @Override public void write(byte[] b) throws IOException { super.write(b); if (out != null) { synchronized (this) { if (out != null) { out.write(b); } } } } @Override public void write(byte[] b, int offset, int len) throws IOException { super.write(b, offset, len); if (out != null) { synchronized (this) { if (out != null) { out.write(b, offset, len); } } } } public void setOutputStream(OutputStream out) { synchronized (this) { this.out = out; } } } }