On Fri, Jul 24, 2009 at 9:35 AM, Peter Westlakepeter.westlake@pobox.com wrote:
Hello,
I'm having trouble with an AMP connection that doesn't fire the Deferred returned by callRemote. The AMP command copies files from the client (called a "worker" in the code below) to a server ("controller"). It sends a chunk of text at a time - 16K originally, but I tried smaller amounts too. The server appends the text to a queue to be written; it shouldn't take long, because it doesn't do the I/O synchronously, just starts a thread.
"justs starts a thread"? Where are you starting a thread in the code example you've posted?
What happens is that the client calls callRemote, but the Deferred that callRemote returns is never fired. I know the command reaches the server, because the client keeps track of how many bytes have been sent successfully, and the file on the server is bigger than that. I know that the Deferred doesn't fire, because I can examine it using a manhole and it has called = False.
There are no error messages in the log. That's consistent with the Deferred not firing, because the error callback (self.next_or_retry) would log a message if the remote command failed.
So, what can possibly be happening? And how can I find out?
All suggestions most gratefully received.
Please post a complete example; I don't see methods on client code below such as send_next() or next_or_retry(). It's hard to help without a complete example. In general, though, if you're trying to debug Deferreds you might try setting debugging with defer.setDebugging(1).
Peter.
Client-side code:
class ConnectionBuffer(object): """Class to store AMP commands and retry them after network outages. ... """
def send(self, adv_arg, *a, **kw): if self.protocol: # call_d is here purely to make the Deferred accessible when debugging. self.call_d = self.protocol.callRemote(*a, **kw).addBoth(self.next_or_retry, adv_arg)
def connected(self, protocol): self.protocol = protocol self.send_next()
def disconnected(self): self.protocol = None
Server:
class ControllerProtocol(amp.AMP): """Protocol used by the controller to communicate with a worker. ... """
def logoutput(self, product, branch, site, job, action, number, data, stream): """Receive stdout or stderr from an action running on a worker.""" actid = (product, branch, site, job, action) ac = self.factory.controller.actions.find(actid) ac.instances[number].logfile[stream].write(data) return {'status': True} commands.LogOutput.responder(logoutput)
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