From: ara.t.howard@...
Date: 2005-12-04T08:59:53+09:00
Subject: Re: Problem with method that starts process, yields pid then yields return code

On Sun, 4 Dec 2005, x1 wrote:

> I've hacked at it and managed to learn quite a few things in the
> process but I cant seem to assign the Exec class to a DRb server to
> handle requests.
>
> Ideally, the <client> would be able to do something like:

<snip>

     harp:~ > cat servant.rb
     #! /usr/bin/env ruby
     %w( thread drb socket time yaml ).each{|lib| require lib}

     class Execute
       %w( cmd queue pipe pid thread exitstatus alive ).each{|a| attr_accessor a}
       def initialize(cmd)
         @cmd = cmd
         @queue = Queue.new
         @thread = Thread.new(queue) do |q|
           pipe = IO.popen(cmd)
           q.push pipe
           q.push pipe.pid
           begin
             loop{ stdout = pipe.gets or break }
             pipe.close
             q.push $?.exitstatus
           rescue => e
             q.push e
           end
         end
         @pipe = queue.pop
         @pid = queue.pop
         @exitstatus = nil
       end
       def wait
         @exitstatus = @queue.pop
       end
     end

     class Executioner
       def execute cmd
         Execute::new cmd
       end
     end

     mode = ARGV.shift
     hostname = Socket.gethostname
     port = 4501

     case mode
       when %r/server/i
         DRb.start_service "druby://#{ hostname }:#{ port }", Executioner.new
         DRb.thread.join

       when %r/client/i
         DRb.start_service
         executioner = DRbObject.new nil, "druby://#{ hostname }:#{ port }"
         sleep = executioner.execute "ruby -e' sleep 3 and exit 43 '"
         y "start" => Time::now.iso8601
         y "pid" => sleep.pid
         y "exitstatus" => sleep.wait
         y "finish" => Time::now.iso8601
     end



     harp:~ > ./servant.rb server &
     [1] 15727



     harp:~ > ./servant.rb client
     ---
     start: "2005-12-03T16:58:19-07:00"
     ---
     pid: 15729
     ---
     exitstatus: 43
     ---
     finish: "2005-12-03T16:58:22-07:00"


hth.


-a
-- 
===============================================================================
| ara [dot] t [dot] howard [at] noaa [dot] gov
| all happiness comes from the desire for others to be happy.  all misery
| comes from the desire for oneself to be happy.
| -- bodhicaryavatara
===============================================================================