From: Daniel Berger <djberg96@...>
Date: 2008-08-27T05:09:09+09:00
Subject: Re: open3 and background processes



On Aug 26, 1:37 pm, Gennady Bystritsky <Gennady.Bystrit...@quest.com>
wrote:
> IO.readlines will try to read out everything until EOF, hence it "hangs" for long running background processes. Can you use IO.readline instead and modify your spawned program to output a one line message to indicate success? Then it will catch both errors and successful runs.

Ah, ok. This seems to work fine:

program = File.join(Dir.pwd, "miniserver.rb")

cmd = "ruby #{program} &"

Open3.popen3(cmd) do |stdin, stdout, stderr|
   # Use readline, since readlines waits until EOF
   error = stderr.readline

   if error
      error = [error] << stderr.readlines # Get the rest
   end

   puts error if error
end

puts "Done"

Many thanks,

Dan