org.apache.dolphinscheduler.common.shell.AbstractShell Maven / Gradle / Ivy
/*
* 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.dolphinscheduler.common.shell;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Map;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* A base class for running a Unix command.
*
* AbstractShell can be used to run unix commands like du or
* df. It also offers facilities to gate commands by
* time-intervals.
*/
public abstract class AbstractShell {
private static final Logger logger = LoggerFactory.getLogger(AbstractShell.class);
/**
* Time after which the executing script would be timedout
*/
protected long timeOutInterval = 0L;
/**
* If or not script timed out
*/
private AtomicBoolean timedOut;
/**
* refresh interval in msec
*/
private long interval;
/**
* last time the command was performed
*/
private long lastTime;
/**
* env for the command execution
*/
private Map environment;
private File dir;
/**
* sub process used to execute the command
*/
private Process process;
private int exitCode;
/**
* If or not script finished executing
*/
private volatile AtomicBoolean completed;
public AbstractShell() {
this(0L);
}
/**
* @param interval the minimum duration to wait before re-executing the
* command.
*/
public AbstractShell(long interval ) {
this.interval = interval;
this.lastTime = (interval<0) ? 0 : -interval;
}
/**
* set the environment for the command
* @param env Mapping of environment variables
*/
protected void setEnvironment(Map env) {
this.environment = env;
}
/**
* set the working directory
* @param dir The directory where the command would be executed
*/
protected void setWorkingDirectory(File dir) {
this.dir = dir;
}
/**
* check to see if a command needs to be executed and execute if needed
* @throws IOException errors
*/
protected void run() throws IOException {
if (lastTime + interval > System.currentTimeMillis()) {
return;
}
// reset for next run
exitCode = 0;
runCommand();
}
/**
* Run a command actual work
*/
private void runCommand() throws IOException {
ProcessBuilder builder = new ProcessBuilder(getExecString());
Timer timeOutTimer = null;
ShellTimeoutTimerTask timeoutTimerTask = null;
timedOut = new AtomicBoolean(false);
completed = new AtomicBoolean(false);
if (environment != null) {
builder.environment().putAll(this.environment);
}
if (dir != null) {
builder.directory(this.dir);
}
process = builder.start();
ProcessContainer.putProcess(process);
if (timeOutInterval > 0) {
timeOutTimer = new Timer();
timeoutTimerTask = new ShellTimeoutTimerTask(
this);
//One time scheduling.
timeOutTimer.schedule(timeoutTimerTask, timeOutInterval);
}
final BufferedReader errReader =
new BufferedReader(new InputStreamReader(process
.getErrorStream()));
BufferedReader inReader =
new BufferedReader(new InputStreamReader(process
.getInputStream()));
final StringBuilder errMsg = new StringBuilder();
// read error and input streams as this would free up the buffers
// free the error stream buffer
Thread errThread = new Thread() {
@Override
public void run() {
try {
String line = errReader.readLine();
while((line != null) && !isInterrupted()) {
errMsg.append(line);
errMsg.append(System.getProperty("line.separator"));
line = errReader.readLine();
}
} catch(IOException ioe) {
logger.warn("Error reading the error stream", ioe);
}
}
};
try {
errThread.start();
} catch (IllegalStateException ise) { }
try {
// parse the output
parseExecResult(inReader);
exitCode = process.waitFor();
try {
// make sure that the error thread exits
errThread.join();
} catch (InterruptedException ie) {
logger.warn("Interrupted while reading the error stream", ie);
}
completed.set(true);
//the timeout thread handling
//taken care in finally block
if (exitCode != 0) {
throw new ExitCodeException(exitCode, errMsg.toString());
}
} catch (InterruptedException ie) {
throw new IOException(ie.toString());
} finally {
if ((timeOutTimer!=null) && !timedOut.get()) {
timeOutTimer.cancel();
}
// close the input stream
try {
inReader.close();
} catch (IOException ioe) {
logger.warn("Error while closing the input stream", ioe);
}
if (!completed.get()) {
errThread.interrupt();
}
try {
errReader.close();
} catch (IOException ioe) {
logger.warn("Error while closing the error stream", ioe);
}
ProcessContainer.removeProcess(process);
process.destroy();
lastTime = System.currentTimeMillis();
}
}
/**
*
* @return an array containing the command name and its parameters
*/
protected abstract String[] getExecString();
/**
* Parse the execution result
* @param lines lines
* @throws IOException errors
*/
protected abstract void parseExecResult(BufferedReader lines)
throws IOException;
/**
* get the current sub-process executing the given command
* @return process executing the command
*/
public Process getProcess() {
return process;
}
/** get the exit code
* @return the exit code of the process
*/
public int getExitCode() {
return exitCode;
}
/**
* Set if the command has timed out.
*
*/
private void setTimedOut() {
this.timedOut.set(true);
}
/**
* Timer which is used to timeout scripts spawned off by shell.
*/
private static class ShellTimeoutTimerTask extends TimerTask {
private AbstractShell shell;
public ShellTimeoutTimerTask(AbstractShell shell) {
this.shell = shell;
}
@Override
public void run() {
Process p = shell.getProcess();
try {
p.exitValue();
} catch (Exception e) {
//Process has not terminated.
//So check if it has completed
//if not just destroy it.
if (p != null && !shell.completed.get()) {
shell.setTimedOut();
p.destroy();
}
}
}
}
/**
* This is an IOException with exit code added.
*/
public static class ExitCodeException extends IOException {
int exitCode;
public ExitCodeException(int exitCode, String message) {
super(message);
this.exitCode = exitCode;
}
public int getExitCode() {
return exitCode;
}
}
/**
* process manage container
*
*/
public static class ProcessContainer extends ConcurrentHashMap{
private static final ProcessContainer container = new ProcessContainer();
private ProcessContainer(){
super();
}
public static final ProcessContainer getInstance(){
return container;
}
public static void putProcess(Process process){
getInstance().put(process.hashCode(), process);
}
public static int processSize(){
return getInstance().size();
}
public static void removeProcess(Process process){
getInstance().remove(process.hashCode());
}
public static void destroyAllProcess(){
Set> set = getInstance().entrySet();
for (Entry entry : set) {
try{
entry.getValue().destroy();
} catch (Exception e) {
logger.error("Destroy All Processes error", e);
}
}
logger.info("close " + set.size() + " executing process tasks");
}
}
}
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