[Quickfix-developers] QuickFIX Python and Twisted

[Robert P. <rob...@gm...>]

HI Folks,

I'm trying to  build a simply gateway based on QuickFIX with the
python bindings, and the Twisted framework (http://twistedmatrix.com).
I'm finding some kind of threading issue.

My aim is to wrap the quickfix engine with a simple RPC container, so
that one can connect to the daemon and invoke calls like "start",
"stop", "subscribe to data" etc. The twisted framework provides an
asynchronous networking layer to do so.

However things seem to lock up when I invoke the
SocketInitiator.start() method. I can start up the service, and create
the QuickFIX application, and  setup and configure the various
QuickFIX components, ala:

 class MyQFService:
  def __init__
        settings     = quickfix.SessionSettings(configFile)
        application  = MyQFClient(connStr)
        storeFactory = quickfix.OdbcStoreFactory(settings)
        logFactory   = quickfix.OdbcLogFactory(settings)

        self.quickfixSettings = settings
        self.quickfixApplication = application
        self.quickfixStoreFactory = storeFactory
        self.quickfixLogFactory = logFactory

        self.quickfixInitiator = quickfix.SocketInitiator(application,
storeFactory, settings, logFactory)

 When a remote "START" command is issued, the main thread of the
twisted code calls the SocketInitiator to start the QuickFIX thread:

  def startQF(self):
        log.msg("QuickFIX Engine starting.")
        self.quickfixInitiator.start()
        log.msg("QuickFIX Engine started.")
        return defer.succeed("STARTED")

At this point, the quickfix engine thread starts, and I see logon,
heartbeats, and other admin messages. The log message immediately
after the start() call executes, and returns correctly. However, the
main thread of the Twisted application seems to block entirely, and I
don't get any response from the application on subsequent RPC
attempts. At this point the appliction also stops responding to Ctrl-C
on the command line, when before it would gracefully terminate.

It seems as if the quickfix thread has taken over, or more likely is
completely blocking the main twisted thread. Any thoughts on what
might be happening here? My first guess is that it has to do with
logging, but I can't be sure.

thanks for any insight,
rob