Class: SSH

Inherits:
Object
  • Object
show all
Includes:
FakePOpen, Open4
Defined in:
lib/ssh.rb,
lib/ssh_test.rb

Overview

SSH provides a simple streaming ssh command runner. That’s it. This is a one trick pony.

ssh = SSH.new "example.com", "/var/log"
puts ssh.run "ls"

SSH was extracted from rake-remote_task which was extracted from vlad.

SSH’s idea contributed by Joel Parker Henderson.

Defined Under Namespace

Classes: CommandFailedError, Error

Constant Summary collapse

VERSION = 
"1.1.0"

Instance Attribute Summary collapse

Attributes included from FakePOpen

#action, #commands, #error, #input, #output

Instance Method Summary collapse

Methods included from FakePOpen

#popen4, #select

Constructor Details

#initialize(target_host = nil, target_dir = nil) ⇒ SSH

Returns a new instance of SSH.



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# File 'lib/ssh.rb', line 32

def initialize target_host = nil, target_dir = nil
  self.ssh_cmd       = "ssh"
  self.ssh_flags     = []
  self.target_host   = target_host
  self.target_dir    = target_dir

  self.sudo_prompt   = /^Password:/
  self.sudo_password = nil
end

Instance Attribute Details

#ssh_cmd ⇒ Object

Returns the value of attribute ssh_cmd.



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# File 'lib/ssh.rb', line 29

def ssh_cmd
  @ssh_cmd
end

#ssh_flags ⇒ Object

Returns the value of attribute ssh_flags.



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# File 'lib/ssh.rb', line 29

def ssh_flags
  @ssh_flags
end

#sudo_password ⇒ Object

Returns the value of attribute sudo_password.



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# File 'lib/ssh.rb', line 30

def sudo_password
  @sudo_password
end

#sudo_prompt ⇒ Object

Returns the value of attribute sudo_prompt.



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# File 'lib/ssh.rb', line 30

def sudo_prompt
  @sudo_prompt
end

#target_dir ⇒ Object

Returns the value of attribute target_dir.



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# File 'lib/ssh.rb', line 29

def target_dir
  @target_dir
end

#target_host ⇒ Object

Returns the value of attribute target_host.



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# File 'lib/ssh.rb', line 29

def target_host
  @target_host
end

Instance Method Details

#empty_streams(pid, inn, out, err) ⇒ Object 



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# File 'lib/ssh.rb', line 68

def empty_streams pid, inn, out, err
  result  = []
  inn.sync   = true
  streams    = [out, err]
  out_stream = {
    out => $stdout,
    err => $stderr,
  }

  # Handle process termination ourselves
  status = nil
  Thread.start do
    status = Process.waitpid2(pid).last
  end

  until streams.empty? do
    # don't busy loop
    selected, = select streams, nil, nil, 0.1

    next if selected.nil? or selected.empty?

    selected.each do |stream|
      if stream.eof? then
        streams.delete stream if status # we've quit, so no more writing
        next
      end

      data = stream.readpartial(1024)
      out_stream[stream].write data

      if stream == err and data =~ sudo_prompt then
        inn.puts sudo_password
        data << "\n"
        $stderr.write "\n"
      end

      result << data
    end
  end

  return status, result
end

#run(command) ⇒ Object 



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# File 'lib/ssh.rb', line 42

def run command
  command = "cd #{target_dir} && #{command}" if target_dir
  cmd     = [ssh_cmd, ssh_flags, target_host, command].flatten

  if $DEBUG then
    trace = [ssh_cmd, ssh_flags, target_host, "'#{command}'"]
    warn trace.flatten.join ' '
  end

  pid, inn, out, err = popen4(*cmd)

  status, result = empty_streams pid, inn, out, err

  unless status.success? then
    e = status.exitstatus
    c = cmd.join ' '
    raise(CommandFailedError.new(status), "Failed with status #{e}: #{c}")
  end

  result.join
ensure
  inn.close rescue nil
  out.close rescue nil
  err.close rescue nil
end