From: x1 <caldridge@...>
Date: 2005-12-04T08:03:19+09:00
Subject: Re: Problem with method that starts process, yields pid then yields return code

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:

DRb.start_service
sleep =  DRbObject.new(nil, 'druby://server:2001').execute("ruby -e
'sleep 3 and exit 43'")
p sleep.pid
p sleep.wait

I tried everything I could think of but the script kept breaking.
Here's what I've got that DOES work:

require 'drb'
require 'thread'

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

hostname = `hostname`.chomp
port = "4501"

#DRb.start_service "druby://#{hostname}:#{port}", Execute.new
#DRb.thread.join

job = Execute.new("cmd /c ruby -e 'sleep 3 and exit 42'")
puts job.cmd
puts job.pid
puts job.wait

If I uncomment the DRb lines, the server starts but clients throw an error :(



On 12/2/05, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
> On Sat, 3 Dec 2005, x1 wrote:
>
> > it seems to work!!
> >
> > Let me spend some time trying to make sense of it... Thanks
> > soooooooooooooooo much!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> > *grins*
>
> great.
>
> i learned a bit too : didn't know about pipe.pid
>
> cheers.
>
> -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
> ===============================================================================
>
>
>