[obtu]

You're listening for two file descriptor events, so you need some sort of event loop. select can do it but it's low-level; and since there can be only one event loop per program, your choices are frameworks and not simply libraries.

Here's a way to do it with Twisted (docs here: http://twistedmatrix.com/documents/current/core/howto/proces... ):

  from twisted.internet import reactor, protocol

  class PrintAndLogProtocol(protocol.ProcessProtocol):
      def outReceived(self, data):
          # print and log
      errReceived = outReceived

  reactor.spawnProcess(PrintAndLogProtocol(),
       '/path/to/exe', ['exe', 'arg1', 'arg2'])
  reactor.run()