simple-ssh

simple-ssh

A wrapper for the ssh2 client module by Brian White which makes it easier to run a sequence of commands over SSH.

Requirements

• node.js -- v0.8.7 or newer

Install

npm install simple-ssh

Examples

• Echoing out a users PATH:

var SSH = require('simple-ssh');

var ssh = new SSH({
    host: 'localhost',
    user: 'username',
    pass: 'password'
});

ssh.exec('echo $PATH', {
    out: function(stdout) {
        console.log(stdout);
    }
}).start();

/*** Using the `args` options instead ***/
ssh.exec('echo', {
    args: ['$PATH'],
    out: function(stdout) {
        console.log(stdout);
    }
}).start();

• Connecting with the active SSH Agent with Agent Forwarding

var ssh = new ssh({
    host: 'localhost',
    user: 'username',
    agent: process.env.SSH_AUTH_SOCK,
    agentForward: true
})

• Capturing error output:

ssh.exec('this-does-not-exist', {
    err: function(stderr) {
        console.log(stderr); // this-does-not-exist: command not found
    }
}).start();

• Capturing error codes:

ssh.exec('exit 69', {
    exit: function(code) {
        console.log(code); // 69
    }
}).start();

• Chaining commands together:

ssh
    .exec('echo "Node.js"', {
        out: console.log.bind(console)
    })
    .exec('echo "is"', {
        out: console.log.bind(console)
    })
    .exec('echo "awesome!"', {
        out: console.log.bind(console)
    })
    .start();

// Output:
// Node.js
// is
// awesome!

• Get the number of commands:

ssh
    .exec('exit 1')
    .exec('exit 2')
    .exec('exit 3');

console.log(ssh.count()); // 3

• Running a command using sudo

ssh.exec('sudo echo "Pseudo-sudo"', {
    pty: true,
    out: console.log.bind(console)
}).start();

• Resetting a connection and the commands

// Echos out any messages the user sent in if 10 or more have been queued
var msgInterval = setInterval(function() {
    if (ssh.count() > 10) {
        ssh.start();
    }
}, 1000);

socket.on('message', function(msg) {
    // If a 'reset' message is received, clear previous messages
    if (msg === 'reset') {
        ssh.reset(function(err) {
            if (err) {
                throw err;
            }

            ssh.exec('echo "reset"');
        });
    } else {
        ssh.exec('echo "' + msg + '"');
    }
});

• Listening for additional events

ssh.on('error', function(err) {
    console.log('Oops, something went wrong.');
    console.log(err);
    ssh.end();
});

• Event handlers can be chained as well

ssh
    .on('error', onSSHError)
    .on('ready', onSSHReady);

---

API

Functions

• Constructor( [ config ] )
  • config { Object }:
    • config.host { String }: Hostname
    • config.port { Number }: Port number (default: 22)
    • config.user { String }: Username
    • config.pass { String }: Password
    • config.timeout { Number }: Connection timeout in milliseconds (default: 10000)
    • config.key { String }: SSH key
    • config.passphrase { String }: Passphrase
    • config.baseDir { String }: Base directory. If this is set, each command will be preceeded by cd ${this.baseDir}
    • config.agent { String }: Connects with the given SSH agent. If this is set, no need to specify a private key or password.
    • config.agentForward { Boolean }: Set to true to connect with agent forwarding.
• exec( command, [ options ] ): Adds a command to the stack
  • command { String }: Command to be executed
  • options { Object }:
    • options.args { String[] }: Additional command line arguments (default: null)
    • options.out { Function( stdout ) }: stdout handler
      • stdout { String }: Output streamed through stdout
    • options.err { Function( stderr ) }: stderr handler
      • stderr { String }: Output streamed through stderr
    • options.exit { Function( code, stdout, stderr ) }: Exit handler
      • code { Number }: Exit code
      • stdout { String }: All of the standard output concatenated together
      • stderr { String }: All of the error output concatenated together
    • options.pty { Boolean }: Allocates a pseudo-tty, useful for command which require sudo (default: false)
• on( event, callback ): Add a listener for the specified event (Courtesy of @alexjab)
  • event { String }: Event to listen to
  • callback { Function }: Executed on the event
• start( [ options ] ): Starts executing the commands
  • options { Object }:
    • options.success { Function() }: Called on successful connection
    • options.fail { Function( err ) }: Called if the connection failed
      • err { Error }: Error information
• reset( [ callback ] ): Clears the command queue and resets the current connection
  • callback { Function( err ) }: Called when the connection has been successfully reset
    • err { Error }: Error information
• end(): Ends the SSH session (this is automatically called at the end of a command queue).

Properties

• host { String }: Host to connect to
• port { Number }: Port to connect through (default: 22)
• user { String }: User name
• pass { String }: Password
• timeout { Number }: Connection timeout in milliseconds (default: 10000)
• key { String }: SSH key
• baseDir { String }: If set, will change directory to baseDir before each command

Flow Control

Sometimes you may find yourself needing to change which commands are executed. The flow can be changed by returning false from an exit handler.

Note: This only works if false is explicitly returned. "Falsy" values are not sufficient (since undefined is implicitly returned and it's "falsy").

• Ending prematurely:

ssh
    .exec('pwd', {
        exit: function() {
            return false;
        }
    })
    .exec('echo "Not executed"')
    .start();

• Running a new queue of commands:

ssh
    .exec('exit', {
        args: [ Math.round(Math.random()) ],
        exit: function(code) {
            if (code === 1) {
                // Setup the new command queue
                ssh.exec('echo "new queue"');
                return false;
            }
        }
    })
    .exec('exit 0', {
        exit: function() {
            console.log('Previous command did not return false');
        }
    })
    .start();