EventMachine compatible Net::SSH
Ruby
Pull request Compare This branch is 83 commits behind simulacre:master.
Latest commit 82637d8 Apr 25, 2012 Mark Bryars Maintain buffer per shell
Fixes #4 - wait_for consumes too much data

README.md

EM-SSH

Em-ssh is a net-ssh adapter for EventMachine. For the most part you can take any net-ssh code you have and run it in the EventMachine reactor.

Em-ssh is not associated with the Jamis Buck's net-ssh library. Please report any bugs with em-ssh to https://github.com/simulacre/em-ssh/issues

Installation

gem install em-ssh

Synopsis

EM.run do
  EM::Ssh.start(host, user, :password => password) do |ssh|
    # capture all stderr and stdout output from a remote process
    ssh.exec!('uname -a').tap {|r| puts "\nuname: #{r}"}

    # capture only stdout matching a particular pattern
    stdout = ""
    ssh.exec!("ls -l /home") do |channel, stream, data|
      stdout << data if stream == :stdout
    end
    puts "\n#{stdout}"

    # run multiple processes in parallel to completion
    ssh.exec('ping -c 1 www.google.com')
    ssh.exec('ping -c 1 www.yahoo.com')
    ssh.exec('ping -c 1 www.rakuten.co.jp')

    #open a new channel and configure a minimal set of callbacks, then wait for the channel to finishes (closees).
    channel = ssh.open_channel do |ch|
      ch.exec "/usr/local/bin/ruby /path/to/file.rb" do |ch, success|
        raise "could not execute command" unless success

        # "on_data" is called when the process writes something to stdout
        ch.on_data do |c, data|
          $stdout.print data
        end

        # "on_extended_data" is called when the process writes something to stderr
        ch.on_extended_data do |c, type, data|
          $stderr.print data
        end

        ch.on_close { puts "done!" }
      end
    end

    channel.wait

    ssh.close
    EM.stop
  end
end

See http://net-ssh.github.com/ssh/v2/api/index.html

Shell

Em-ssh provides an expect-like shell abstraction layer on top of net-ssh in EM::Ssh::Shell

Example

require 'em-ssh/shell'
EM.run {
  EM::Ssh::Shell.new(host, 'caleb', "") do |shell|
    shell.should be_a(EventMachine::Ssh::Shell)
    shell.wait_for(']$')
    shell.send_and_wait('uname -a', ']$')
    shell.wait_for(']$')
    shell.send_and_wait('/sbin/ifconfig -a', ']$')
    timer.cancel
    EM.stop
  end
}

Synchrony Example

require 'em-ssh/shell'
EM.run {
    Fiber.new {
        shell = EM::Ssh::Shell.new(host, 'caleb', '')
        shell.wait_for(']$')
        shell.send_and_wait('sudo su -', 'password for caleb: ')
        shell.send_and_wait('password', ']$')
        output = shell.send_and_wait('/etc/init.d/openvpn restart', ']$')
        # ...
        shell.send_and_wait('exit', ']$')
        shell.send_data('exit')
    }.resume
}

Other Examples

See bin/em-ssh for an example of a basic replacement for system ssh.

See bin/em-ssh-shell for a more complex example usage of Shell.

Known Issues

Em-ssh relies on Fibers. MRI 1.9.2-p290 on OSX Lion has been known to segfault when using Fibers.

Copyright

Copyright (c) 2011 Caleb Crane

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Portions of this software are Copyright (c) 2008 Jamis Buck