edu.sdsc.inca.agent.access
Class Ssh

java.lang.Object
  edu.sdsc.inca.agent.AccessMethod
      edu.sdsc.inca.agent.access.Ssh

public class Ssh
extends AccessMethod

A class that implements AccessMethod using the SSH protocol for transferring files and running processes on remote resources. Important note: stop() does not kill the remote process currently

Author:

Shava Smallen <ssmallen@sdsc.edu>

Field Summary

static int	CHECK_PERIOD
static java.lang.String[]	SSH_IDENTITY_FILENAMES

Constructor Summary

Ssh(java.lang.String resource, edu.sdsc.inca.util.ResourcesWrapper resources)
Create a new remote process controlling it via SSH.

Method Summary

void	get(java.lang.String[] remoteFiles, java.lang.String localDir) Transfer a list of remote files to a directory on the local machine using SSH.
boolean	isActive() Checks to see if the current ssh session is active.
java.lang.String	prependHome(java.lang.String path) Given a path relative to the home directory, prepend the home directory to the path and return the new string.
void	put(java.lang.String[] localFiles, java.lang.String remoteDir) Transfer a list of local files to a directory on a remote machine using SSH.
AccessMethodOutput	run(java.lang.String executable, java.lang.String[] arguments, java.lang.String stdin, java.lang.String directory) Execute the specified process on the remote resource.
void	start(java.lang.String executable, java.lang.String[] arguments, java.lang.String stdin, java.lang.String directory) Start a process on a remote machine.
void	stop() This call should kill the remote process that was started by the start() call.

Methods inherited from class edu.sdsc.inca.agent.AccessMethod

create, get, put, run, run, start, start

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CHECK_PERIOD

public static final int CHECK_PERIOD

See Also:

Constant Field Values

SSH_IDENTITY_FILENAMES

public static final java.lang.String[] SSH_IDENTITY_FILENAMES

Constructor Detail

Ssh

public Ssh(java.lang.String resource,
           edu.sdsc.inca.util.ResourcesWrapper resources)
    throws edu.sdsc.inca.ConfigurationException

Create a new remote process controlling it via SSH. The given resource should exist in the resource configuration file and the following fields can be optionally defined: sshServer - the remote hostname [default: resource name] sshPort - alternative port of SSH server [default: SSHClient's default] sshUsername - username on remote machine [default: user.home from Java] sshPrivateKeyFile - identity to use to authenticate [default: ~/.ssh/id_dsa, ~/.ssh/id_rsa]

Parameters:

resource - The name of the resource to start the process on

resources - The resource configuration information.

Throws:

edu.sdsc.inca.ConfigurationException - if problem configuring ssh connection

Method Detail

get

public void get(java.lang.String[] remoteFiles,
                java.lang.String localDir)
         throws AccessMethodException

Transfer a list of remote files to a directory on the local machine using SSH.

Overrides:

get in class AccessMethod

Parameters:

remoteFiles - List of paths to remote files that will be transfered

localDir - Path to the directory on the local machine where the remote files will be placed

Throws:

AccessMethodException

isActive

public boolean isActive()
                 throws AccessMethodException

Checks to see if the current ssh session is active. Does not indicate whether the remote process is alive (for now).

Specified by:

isActive in class AccessMethod

Returns:

true if the SSH session is alive; false otherwise.

Throws:

AccessMethodException - if unable to determine if process is active

prependHome

public java.lang.String prependHome(java.lang.String path)

Given a path relative to the home directory, prepend the home directory to the path and return the new string.

Overrides:

prependHome in class AccessMethod

Parameters:

path - A path relative to the user's home directory

Returns:

A new string that contains the home directory prepended to the provided path.

run

public AccessMethodOutput run(java.lang.String executable,
                              java.lang.String[] arguments,
                              java.lang.String stdin,
                              java.lang.String directory)
                       throws AccessMethodException,
                              java.lang.InterruptedException

Execute the specified process on the remote resource. This call will block until the process has completed.

Specified by:

run in class AccessMethod

Parameters:

executable - Path to the remote executable.

arguments - Contains the arguments that should be passed to the executable

stdin - A string that will be passedd in as stdin to the process when it is started

directory - Path to the directory where the process will be executed from

Returns:

The stdout and stderr of the executed process in AccessMethodOutput

Throws:

AccessMethodException - if unable to execute remote process

java.lang.InterruptedException - if interrupted while running remote process

start

public void start(java.lang.String executable,
                  java.lang.String[] arguments,
                  java.lang.String stdin,
                  java.lang.String directory)
           throws AccessMethodException

Start a process on a remote machine. This is a non-blocking call. Important note: this process will not be killed on call to stop()

Specified by:

start in class AccessMethod

Parameters:

executable - Path to the remote executable.

arguments - Contains the arguments that should be passed to the executable

directory - Path to the directory where the process will be executed

stdin - A string that will be passedd in as stdin to the process when it is started

Throws:

AccessMethodException

stop

public void stop()
          throws AccessMethodException

This call should kill the remote process that was started by the start() call. However, since a remote process won't be killed when the ssh client session is closed, the remote process will persist. Will try to figure out if there is a SSH configuration mechanism that can be turned on so that the process will be killed upon disconnect. This call does disconnect the active SSH session.

Specified by:

stop in class AccessMethod

Throws:

AccessMethodException

put

public void put(java.lang.String[] localFiles,
                java.lang.String remoteDir)
         throws AccessMethodException

Transfer a list of local files to a directory on a remote machine using SSH.

Overrides:

put in class AccessMethod

Parameters:

localFiles - List of paths to local files that will be transfered

remoteDir - Path to the directory on the remote machine where the local files will be placed

Throws:

AccessMethodException