even better timeout handling for ssh pipes

lib/hydra/master.rb

@@ -172,7 +172,7 @@ module Hydra #:nodoc:
 
         trace "Booting SSH worker"
         trace command
-        ssh = Hydra::SSH.new("#{sync.ssh_opts} #{sync.connect}", sync.remote_dir, command)
+        ssh = Hydra::SSH.new("#{sync.ssh_opts} #{sync.connect}", sync.remote_dir, command, worker['timeout'])
         return { :io => ssh, :idle => false, :type => :ssh, :connect => sync.connect }
       else
         false

lib/hydra/messaging_io.rb

@@ -11,7 +11,10 @@ module Hydra #:nodoc:
       while true
         begin
           raise IOError unless @reader
-          message = @reader.gets
+          if !@timeout || (result = Kernel.select([@reader], [], [], @timeout))
+            message = @reader.gets
+          end
+          return Message.build(:class => Hydra::Messages::Master::Shutdown) if result == nil
           return nil unless message
           return Message.build(eval(message.chomp))
         rescue SyntaxError, NameError

lib/hydra/pipe.rb

@@ -31,9 +31,10 @@ module Hydra #:nodoc:
   class Pipe
     include Hydra::MessagingIO
     # Creates a new uninitialized pipe pair.
-    def initialize
+    def initialize(timeout = nil)
       @child_read, @parent_write = IO.pipe
       @parent_read, @child_write = IO.pipe
+      @timeout = timeout
     end
 
     # Identify this side of the pipe as the child.

lib/hydra/ssh.rb

@@ -25,7 +25,8 @@ module Hydra #:nodoc:
     #   Hydra::SSH.new('-p 3022 user@server.com', '/home/user/Desktop', 'ls -l')
     # To connect to server.com as user on port 3022, then CD to their desktop, then
     # list all the files.
-    def initialize(connection_options, directory, command)
+    def initialize(connection_options, directory, command, timeout = nil)
+      @timeout = timeout
       @writer, @reader, @error = popen3(%{ssh -tt #{connection_options} 'mkdir -p #{directory} && cd #{directory} && #{command}'})
     end
   end