From: "list. rb" <list.rb@...>
Date: 2008-10-21T11:42:20+09:00
Subject: Re: Block method to yield stdout?

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On Mon, Oct 20, 2008 at 5:13 PM, Mark Thomas <mark@thomaszone.com> wrote:

> On Oct 20, 2:19 pm, "List.rb" <list...@gmail.com> wrote:
>
> > In my Task class, I would like to create a block method such as
> > 'Task.monitor(mode="stdout")', which would yield the stdout for that
> > task from that point forward. -- similar to tail -f
>
> Have you seen File::Tail?
> http://file-tail.rubyforge.org/doc/index.html
>
> -- Mark.
>
>
Thanks Mark for replying. Yes I have used Tail before but what I'm looking
for is more along the lines of a non-blocking version of IO#readlines

Currently, I do this on the server side:

def spawn(job)
   task = Task.new(job)
   queue = Queue.new
   Thread.new(queue) {|q|
       pipe = IO.popen(task.job.cmd)
       q.push(pipe)
       q.push(pipe.pid)
       task.pid = pipe.pid
       begin
           Thread.new {
             task.output = pipe.readlines
             pipe.close
             task.exitstatus = $?.exitstatus
             task.history << {:completed => Time.now}
           }
        rescue => e
            q.push e
       end
    }
    queue.clear
    self.tasks.push(task)
    return task
end

Since IO#readlines blocks, I am not sure how to tap into the process output
:-(

Thanks again

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