On 30/09/2010 15:23, Phil Mayers wrote:
def loop(): d = maybeDeferred(doStuff) d.addErrback(partial(log.err,_why='Unhandled scheduled exception'))
So, how come my log.err doesn't get used for the AttributeError on connector?
If you mean in your most recent "test_looping.py" example, it still uses reactor.callLater. The call stack has gone away by the time the call is made, so the exception just propagates up to the top level, where it's logged.
So, I appear to be back to the case where I can either gracefully handle the exception *or* gracefully handle the errback, but not both?
I honestly think a more complete example showing the real Twisted API that's causing you unhandled errors would help here.
Unfortunately, you neither want to see, nor am I allowed to publish to a mailing list, that several hundred lines of proprietary code I'd need to post... As far as the original error goes, we hit the problem using twisted.protocols.ftp.FTPClient to ftp a file up to a remote host. That remote host only accepts active ftp transfers. As a result of either of both of our firewall or FTPClient not handling active ftp and only handling passive ftp, we end up seeing the following logging as the scheduler dies: 2010-09-27 15:30:16,340 ERROR : log (24331|7f2e47b4d6e0): Unhandled exception sending schedule transmission Traceback (most recent call last): File "Twisted-8.2.0-py2.5-linux-x86_64.egg/twisted/python/context.py", line 37, in callWithContext return func(*args,**kw) File "Twisted-8.2.0-py2.5-linux-x86_64.egg/twisted/internet/selectreactor.py", line 146, in _doReadOrWrite why = getattr(selectable, method)() File "Twisted-8.2.0-py2.5-linux-x86_64.egg/twisted/internet/tcp.py", line 631, in doConnect self.failIfNotConnected(error.getConnectError((err, strerror(err)))) File "Twisted-8.2.0-py2.5-linux-x86_64.egg/twisted/internet/tcp.py", line 588, in failIfNotConnected del self.connector --- <exception caught here> --- File "ourcode.py", line 180, in checkSchedule yield self.sendTransmissions(...) exceptions.GeneratorExit: 2010-09-27 15:30:28,428 ERROR : log (24331|7f2e47b4d6e0): Unhandled error in Deferred: 2010-09-27 15:30:28,584 ERROR : log (24331|7f2e47b4d6e0): Unhandled Error Traceback (most recent call last): Failure: twisted.protocols.ftp.FTPError: ('Connection Failed', <twisted.python.failure.Failure <class 'twisted.internet.error.ConnectError'>>) I can't quite make sense of the above, which is why I distilled it down to as-small-as-possible a piece of code that shows the type of exceptions and errbacks I need to deal with... cheers, Chris -- Simplistix - Content Management, Batch Processing & Python Consulting - http://www.simplistix.co.uk