vaguerent/lib/vagrant/ssh/session.rb
2011-01-12 15:29:53 -08:00

108 lines
3.6 KiB
Ruby

module Vagrant
class SSH
# A helper class which wraps around `Net::SSH::Connection::Session`
# in order to provide basic command error checking while still
# providing access to the actual session object.
class Session
include Util::Retryable
attr_reader :session
def initialize(session)
@session = session
end
# Opens a shell with this SSH session, which forces things like the
# `/etc/profile` script to load, and for state to exist between commands,
# and so on. The overhead on this is much higher than simply calling
# {#exec!} and should really only be called when settings for the terminal
# may be needed (for things such as a PATH modifications and so on).
def shell
session.shell do |sh|
sh.on_process_run do |sh, process|
# Enable error checking by default
process.properties[:error_check] = true if !process.properties.has_key?(:error_check)
process.on_finish do |p|
# By default when a process finishes we want to check the exit
# status so we can properly raise an exception
self.check_exit_status(p.exit_status, p.command, p.properties) if p.properties[:error_check]
end
end
yield sh
# Exit and wait. We don't run shell commands in the background.
sh.execute "exit", :error_check => false
sh.wait!
end
end
# Executes a given command and simply returns true/false if the
# command succeeded or not.
def test?(command)
exec!(command) do |ch, type, data|
return true if type == :exit_status && data == 0
end
false
end
# Executes a given command on the SSH session and blocks until
# the command completes. This is an almost line for line copy of
# the actual `exec!` implementation, except that this
# implementation also reports `:exit_status` to the block if given.
def exec!(command, options=nil, &block)
options = { :error_check => true }.merge(options || {})
block ||= Proc.new do |ch, type, data|
check_exit_status(data, command, options) if type == :exit_status && options[:error_check]
ch[:result] ||= ""
ch[:result] << data if [:stdout, :stderr].include?(type)
end
retryable(:tries => 5, :on => IOError, :sleep => 0.5) do
metach = session.open_channel do |channel|
channel.exec(command) do |ch, success|
raise "could not execute command: #{command.inspect}" unless success
# Output stdout data to the block
channel.on_data do |ch2, data|
block.call(ch2, :stdout, data)
end
# Output stderr data to the block
channel.on_extended_data do |ch2, type, data|
block.call(ch2, :stderr, data)
end
# Output exit status information to the block
channel.on_request("exit-status") do |ch2, data|
block.call(ch2, :exit_status, data.read_long)
end
end
end
metach.wait
metach[:result]
end
end
# Checks for an erroroneous exit status and raises an exception
# if so.
def check_exit_status(exit_status, command, options=nil)
if exit_status != 0
options = {
:_error_class => Errors::VagrantError,
:_key => :ssh_bad_exit_status,
:command => command
}.merge(options || {})
raise options[:_error_class], options
end
end
end
end
end