From: x1 <caldridge@...>
Date: 2005-12-06T10:30:51+09:00
Subject: Re: Problem with method that starts process, yields pid then yields return code

And here's the results from windows:

Desktop>process.rb client
starting @ Mon Dec 05 20:27:42 Eastern Standard Time 2005
940
Mon Dec 05 20:27:42 Eastern Standard Time 2005
43
Mon Dec 05 20:27:42 Eastern Standard Time 2005
Finished @ Mon Dec 05 20:27:42 Eastern Standard Time 2005

What's actually happening, is when this is executed:
sleep = executioner.execute "ruby -e' sleep 3 and exit 43 '"

Windows waits until the job finishes, and then continues to the next
line...(no fork I guess) Just weird how it worked in the original
example...

On 12/5/05, x1 <caldridge@gmail.com> wrote:
> So... I just restarted and booted into SUSE..
>
> The example works perfect under linux... --weird.
> To explain what I'm seeing, I added the output of Time.now directly
> after printing the pid & exit status..
>
> linux>ruby process.rb client
> ---
> start: "2005-12-05T20:20:32-05:00"
> ---
> pid: 7712
> ---
> x: "2005-12-05T20:20:32-05:00"
> ---
> exitstatus: 43
> ---
> x: "2005-12-05T20:20:35-05:00"
> ---
> finish: "2005-12-05T20:20:35-05:00"
>
> As we see, it instantly gave me the pid and took two seconds to tell
> me the exitstatus. (which is what I want) but with windows, it takes 2
> seconds to get anything back. I'll reboot and run the same script in
> windows..
>
>
> On 12/5/05, x1 <caldridge@gmail.com> wrote:
> > weird thing is, with your first example, the pid prints out before the
> > command finishes... where with the second example, nothing is printed
> > out until the command exits.
> >
> > On 12/5/05, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
> > > On Tue, 6 Dec 2005, x1 wrote:
> > >
> > > > What we have so far works, however ideally, printing the pid should not rely
> > > > on the completion of the job. The only thing that should rely on the
> > > > completion of the job would be outputting the exitstatus.
> > >
> > > but that is the exactly the case? example:
> > >
> > >    harp:~ > ruby servant.rb server &
> > >    [2] 31570
> > >
> > >
> > >    harp:~ > ruby servant.rb client
> > >    ---
> > >    start: "2005-12-05T16:29:21-07:00"
> > >    ---
> > >    pid: 31572
> > >    ---
> > >    after getting pid...: "2005-12-05T16:29:21-07:00"
> > >    ---
> > >    exitstatus: 43
> > >    ---
> > >    finish: "2005-12-05T16:29:24-07:00"
> > >
> > >
> > > note the times.  __only__ getting the exitstatus relies on job completion (by
> > > definition) and is a blocking operation.
> > >
> > > before i read more of your post make sure you understand the above.  the code
> > > again:
> > >
> > >    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, hostname, port = ARGV.shift, Socket.gethostname, 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 "after getting pid..." => Time::now.iso8601
> > >        y "exitstatus" => sleep.wait
> > >        y "finish" => Time::now.iso8601
> > >    end
> > >
> > >
> > > regarding your questions about 'initialize' and 'new' - ruby is object
> > > orientied.  everything is an object constructed from a class.  the method new,
> > > when called on a class returns an object which was created an initialized
> > > using it's initialize method.  check out the 'pickaxe' and the 'ruby way' for
> > > deep insight into ruby - you can't code without them.
> > >
> > > kind regards.
> > >
> > > -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
> > > ===============================================================================
> > >
> > >
> > > cat a.rb
> > >
> > >
> >
> >
>
>