I'm using SSHExec ant task to connect to a remote host and I depend on the environment variables that are set on the remote host in order to be able to successfully execute some commands.
<sshexec host="somehost"
username="${username}"
password="${password}"
command="set"/>
Using the task the env. variables that are outputed are not the same as the ones I get when I log in using an SSH Client.
How can I make the env. variables of the remote host avaiable for the session?
I've found out that the current SSHExeec task implementation is using JSCh's ChannelExec (remote execution of commands) instead of a ChannelShell (remote shell) as connection channel.
That means that apparentely as per JSCh's current implementation a ChannelExec doesn't load env. variables.
I'm still not sure wether this is a limitation on the protocol or on the API.
The conclusion is that as for now there's no solution for the problem, unless you implement your own Ant task.
A working draft of how it would be:
package org.apache.tools.ant.taskdefs.optional.ssh;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.io.StringReader;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.resources.FileResource;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.util.KeepAliveOutputStream;
import org.apache.tools.ant.util.TeeOutputStream;
import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
/**
* Executes a command on a remote machine via ssh.
* @since Ant 1.6 (created February 2, 2003)
*/
public class SSHExecShellSupport extends SSHBase {
private static final String COMMAND_SEPARATOR = System.getProperty("line.separator");
private static final int BUFFER_SIZE = 8192;
private static final int RETRY_INTERVAL = 500;
/** the command to execute via ssh */
private String command = null;
/** units are milliseconds, default is 0=infinite */
private long maxwait = 0;
/** for waiting for the command to finish */
private Thread thread = null;
private String outputProperty = null; // like <exec>
private File outputFile = null; // like <exec>
private boolean append = false; // like <exec>
private Resource commandResource = null;
private boolean isShellMode;
private long maxTimeWithoutAnyData = 1000*10;
private static final String TIMEOUT_MESSAGE =
"Timeout period exceeded, connection dropped.";
public long getMaxTimeWithoutAnyData() {
return maxTimeWithoutAnyData;
}
public void setMaxTimeWithoutAnyData(long maxTimeWithoutAnyData) {
this.maxTimeWithoutAnyData = maxTimeWithoutAnyData;
}
public boolean isShellMode() {
return isShellMode;
}
public void setShellMode(boolean isShellMode) {
this.isShellMode = isShellMode;
}
/**
* Constructor for SSHExecTask.
*/
public SSHExecShellSupport() {
super();
}
/**
* Sets the command to execute on the remote host.
*
* @param command The new command value
*/
public void setCommand(String command) {
this.command = command;
}
/**
* Sets a commandResource from a file
* @param f the value to use.
* @since Ant 1.7.1
*/
public void setCommandResource(String f) {
this.commandResource = new FileResource(new File(f));
}
/**
* The connection can be dropped after a specified number of
* milliseconds. This is sometimes useful when a connection may be
* flaky. Default is 0, which means "wait forever".
*
* @param timeout The new timeout value in seconds
*/
public void setTimeout(long timeout) {
maxwait = timeout;
}
/**
* If used, stores the output of the command to the given file.
*
* @param output The file to write to.
*/
public void setOutput(File output) {
outputFile = output;
}
/**
* Determines if the output is appended to the file given in
* <code>setOutput</code>. Default is false, that is, overwrite
* the file.
*
* @param append True to append to an existing file, false to overwrite.
*/
public void setAppend(boolean append) {
this.append = append;
}
/**
* If set, the output of the command will be stored in the given property.
*
* @param property The name of the property in which the command output
* will be stored.
*/
public void setOutputproperty(String property) {
outputProperty = property;
}
/**
* Execute the command on the remote host.
*
* @exception BuildException Most likely a network error or bad parameter.
*/
public void execute() throws BuildException {
if (getHost() == null) {
throw new BuildException("Host is required.");
}
if (getUserInfo().getName() == null) {
throw new BuildException("Username is required.");
}
if (getUserInfo().getKeyfile() == null
&& getUserInfo().getPassword() == null) {
throw new BuildException("Password or Keyfile is required.");
}
if (command == null && commandResource == null) {
throw new BuildException("Command or commandResource is required.");
}
if(isShellMode){
shellMode();
} else {
commandMode();
}
}
private void shellMode() {
final Object lock = new Object();
Session session = null;
try {
session = openSession();
final Channel channel=session.openChannel("shell");
final PipedOutputStream pipedOS = new PipedOutputStream();
PipedInputStream pipedIS = new PipedInputStream(pipedOS);
final Thread commandProducerThread = new Thread("CommandsProducerThread"){
public void run() {
BufferedReader br = null;
try {
br = new BufferedReader(new InputStreamReader(commandResource.getInputStream()));
String singleCmd;
synchronized (lock) {
lock.wait(); // waits for the reception of the very first data (before commands are issued)
while ((singleCmd = br.readLine()) != null) {
singleCmd += COMMAND_SEPARATOR;
log("cmd : " + singleCmd, Project.MSG_INFO);
pipedOS.write(singleCmd.getBytes());
lock.notify();
try {
lock.wait();
} catch (InterruptedException e) {
log(e, Project.MSG_VERBOSE);
break;
}
}
log("Finished producing commands", Project.MSG_VERBOSE);
}
} catch (IOException e) {
log(e, Project.MSG_VERBOSE);
} catch (InterruptedException e) {
log(e, Project.MSG_VERBOSE);
} finally {
FileUtils.close(br);
}
}
};
ByteArrayOutputStream out = new ByteArrayOutputStream();
final TeeOutputStream tee = new TeeOutputStream(out, new KeepAliveOutputStream(System.out));
channel.setOutputStream(tee);
channel.setExtOutputStream(tee);
channel.setInputStream(pipedIS);
channel.connect();
// waits for it to finish receiving data response and then ask for another the producer to issue one more command
thread = new Thread("DataReceiverThread") {
public void run() {
long lastTimeConsumedData = System.currentTimeMillis(); // initializes the watch
try {
InputStream in = channel.getInputStream();
byte[] tmp = new byte[1024];
while (true) {
if(thread == null){ // works with maxTimeout (for the whole task to complete)
break;
}
while (in.available() > 0) {
int i = in.read(tmp, 0, 1024);
lastTimeConsumedData = System.currentTimeMillis();
if (i < 0){
break;
}
tee.write(tmp, 0, i);
}
if (channel.isClosed()) {
log("exit-status: " + channel.getExitStatus(), Project.MSG_INFO);
log("channel.isEOF(): " + channel.isEOF(), Project.MSG_VERBOSE);
log("channel.isConnected(): " + channel.isConnected(), Project.MSG_VERBOSE);
throw new BuildException("Connection lost."); // NOTE: it also can happen that if one of the command are "exit" the channel will be closed!
}
synchronized(lock){
long elapsedTimeWithoutData = (System.currentTimeMillis() - lastTimeConsumedData);
if (elapsedTimeWithoutData > maxTimeWithoutAnyData) {
log(elapsedTimeWithoutData / 1000 + " secs elapsed without any data reception. Notifying command producer.", Project.MSG_VERBOSE);
lock.notify(); // command producer is waiting for this
try {
lock.wait(500); // wait til we have new commands.
Thread.yield();
log("Continuing consumer loop. commandProducerThread.isAlive()?" + commandProducerThread.isAlive(), Project.MSG_VERBOSE);
if(!commandProducerThread.isAlive()){
log("No more commands to be issued and it's been too long without data reception. Exiting consumer.", Project.MSG_VERBOSE);
break;
}
} catch (InterruptedException e) {
log(e, Project.MSG_VERBOSE);
break;
}
lastTimeConsumedData = System.currentTimeMillis(); // resets watch
}
}
}
} catch (IOException e) {
throw new BuildException(e);
}
}
};
thread.start();
commandProducerThread.start();
thread.join(maxwait);
if (thread.isAlive()) {
// ran out of time
thread = null;
if (getFailonerror()) {
throw new BuildException(TIMEOUT_MESSAGE);
} else {
log(TIMEOUT_MESSAGE, Project.MSG_ERR);
}
} else {
//success
if (outputFile != null) {
writeToFile(out.toString(), append, outputFile);
}
// this is the wrong test if the remote OS is OpenVMS,
// but there doesn't seem to be a way to detect it.
log("Exit status (not reliable): " + channel.getExitStatus(), Project.MSG_INFO);
// int ec = channel.getExitStatus(); FIXME
// if (ec != 0) {
// String msg = "Remote command failed with exit status " + ec;
// if (getFailonerror()) {
// throw new BuildException(msg);
// } else {
// log(msg, Project.MSG_ERR);
// }
// }
}
} catch (Exception e){
throw new BuildException(e);
} finally {
if (session != null && session.isConnected()) {
session.disconnect();
}
}
}
private void commandMode() {
Session session = null;
try {
session = openSession();
/* called once */
if (command != null) {
log("cmd : " + command, Project.MSG_INFO);
ByteArrayOutputStream out = executeCommand(session, command);
if (outputProperty != null) {
//#bugzilla 43437
getProject().setNewProperty(outputProperty, command + " : " + out);
}
} else { // read command resource and execute for each command
try {
BufferedReader br = new BufferedReader(
new InputStreamReader(commandResource.getInputStream()));
String cmd;
String output = "";
while ((cmd = br.readLine()) != null) {
log("cmd : " + cmd, Project.MSG_INFO);
ByteArrayOutputStream out = executeCommand(session, cmd);
output += cmd + " : " + out + "\n";
}
if (outputProperty != null) {
//#bugzilla 43437
getProject().setNewProperty(outputProperty, output);
}
FileUtils.close(br);
} catch (IOException e) {
throw new BuildException(e);
}
}
} catch (JSchException e) {
throw new BuildException(e);
} finally {
if (session != null && session.isConnected()) {
session.disconnect();
}
}
}
private ByteArrayOutputStream executeCommand(Session session, String cmd)
throws BuildException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
TeeOutputStream tee = new TeeOutputStream(out, new KeepAliveOutputStream(System.out));
try {
final ChannelExec channel;
session.setTimeout((int) maxwait);
/* execute the command */
channel = (ChannelExec) session.openChannel("exec");
channel.setCommand(cmd);
channel.setOutputStream(tee);
channel.setExtOutputStream(tee);
channel.connect();
// wait for it to finish
thread =
new Thread() {
public void run() {
while (!channel.isClosed()) {
if (thread == null) {
return;
}
try {
sleep(RETRY_INTERVAL);
} catch (Exception e) {
// ignored
}
}
}
};
thread.start();
thread.join(maxwait);
if (thread.isAlive()) {
// ran out of time
thread = null;
if (getFailonerror()) {
throw new BuildException(TIMEOUT_MESSAGE);
} else {
log(TIMEOUT_MESSAGE, Project.MSG_ERR);
}
} else {
//success
if (outputFile != null) {
writeToFile(out.toString(), append, outputFile);
}
// this is the wrong test if the remote OS is OpenVMS,
// but there doesn't seem to be a way to detect it.
int ec = channel.getExitStatus();
if (ec != 0) {
String msg = "Remote command failed with exit status " + ec;
if (getFailonerror()) {
throw new BuildException(msg);
} else {
log(msg, Project.MSG_ERR);
}
}
}
} catch (BuildException e) {
throw e;
} catch (JSchException e) {
if (e.getMessage().indexOf("session is down") >= 0) {
if (getFailonerror()) {
throw new BuildException(TIMEOUT_MESSAGE, e);
} else {
log(TIMEOUT_MESSAGE, Project.MSG_ERR);
}
} else {
if (getFailonerror()) {
throw new BuildException(e);
} else {
log("Caught exception: " + e.getMessage(),
Project.MSG_ERR);
}
}
} catch (Exception e) {
if (getFailonerror()) {
throw new BuildException(e);
} else {
log("Caught exception: " + e.getMessage(), Project.MSG_ERR);
}
}
return out;
}
/**
* Writes a string to a file. If destination file exists, it may be
* overwritten depending on the "append" value.
*
* @param from string to write
* @param to file to write to
* @param append if true, append to existing file, else overwrite
* @exception Exception most likely an IOException
*/
private void writeToFile(String from, boolean append, File to)
throws IOException {
FileWriter out = null;
try {
out = new FileWriter(to.getAbsolutePath(), append);
StringReader in = new StringReader(from);
char[] buffer = new char[BUFFER_SIZE];
int bytesRead;
while (true) {
bytesRead = in.read(buffer);
if (bytesRead == -1) {
break;
}
out.write(buffer, 0, bytesRead);
}
out.flush();
} finally {
if (out != null) {
out.close();
}
}
}
}