/*
* Copyright (C) 2006-2016 DLR, Germany
*
* All rights reserved
*
* http://www.rcenvironment.de/
*/
package de.rcenvironment.core.utils.ssh.jsch.executor;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import de.rcenvironment.core.utils.executor.RCECommandLineExecutor;
/**
* A {@link CommandLineExecutor} that delegates execution over an established JSch connection to an RCE instance. The
* current implementation expects the remote system to provide an RCE command console.
*
* @author Brigitte Boden
* @author Robert Mischke
*/
public class JSchRCECommandLineExecutor implements RCECommandLineExecutor {
private static final String EXCEPTION_MESSAGE_NOT_RUNNING = "Not running";
private static final String EXCEPTION_MESSAGE_ALREADY_RUNNING = "Already running";
private static final int TERMINATION_POLLING_INTERVAL_MSEC = 1000;
private Session jschSession;
private ChannelExec executionChannel;
private Log log = LogFactory.getLog(getClass());
private InputStream stdoutStream;
private InputStream stderrStream;
/**
* @param jschSession an established JSch session
*/
public JSchRCECommandLineExecutor(Session jschSession) {
this.jschSession = jschSession;
}
@Override
public InputStream getStderr() throws IOException {
if (executionChannel == null) {
throw new IllegalStateException(EXCEPTION_MESSAGE_NOT_RUNNING);
}
return stderrStream;
}
@Override
public InputStream getStdout() throws IOException {
if (executionChannel == null) {
throw new IllegalStateException(EXCEPTION_MESSAGE_NOT_RUNNING);
}
return stdoutStream;
}
@Override
public void start(String commandString) throws IOException {
start(commandString, null);
}
@Override
public void start(String commandString, InputStream stdinStream) throws IOException {
if (executionChannel != null) {
throw new IllegalStateException(EXCEPTION_MESSAGE_ALREADY_RUNNING);
}
StringBuilder command = new StringBuilder();
command.append(commandString);
try {
executionChannel = (ChannelExec) jschSession.openChannel("exec");
String fullCommand = command.toString();
log.debug("Full invocation command: " + fullCommand);
executionChannel.setCommand(fullCommand);
if (stdinStream != null) {
executionChannel.setInputStream(stdinStream);
}
stdoutStream = executionChannel.getInputStream();
stderrStream = executionChannel.getExtInputStream();
executionChannel.connect();
} catch (JSchException e) {
throw new IOException(e);
}
}
@Override
public int waitForTermination() throws IOException, InterruptedException {
if (executionChannel == null) {
throw new IllegalStateException(EXCEPTION_MESSAGE_NOT_RUNNING);
}
try {
while (!executionChannel.isClosed()) {
Thread.sleep(TERMINATION_POLLING_INTERVAL_MSEC);
}
return executionChannel.getExitStatus();
} finally {
// note: this is called AFTER getExitStatus during normal execution flow
executionChannel.disconnect();
executionChannel = null;
}
}
}