Exceptions raised in @app.route-decorated functions are passed to log.err twice

[philmayers]

The "processing_failed" function calls log.err on any exception:

https://github.com/twisted/klein/blob/master/klein/resource.py#L125

...but it also calls t.web Request.processingFailed which also calls log.err:

https://github.com/twisted/twisted/blob/trunk/twisted/web/server.py#L314

But the failure is also passed to log.err when the Deferred is garbage-collected.

This means errors/tracebacks are logged twice - not useful.

[philmayers]

Actually that can't be quite right, because it calls return right after request.processingFailed. But I am seeing double-logging of tracebacks.

[philmayers]

Ok, have checked the call stacks for the two log.err calls

One is in Request.processingFailed as above, the other is when the deferred is garbage-collected ("Unhandled error in deferred")

Since klein is generating the deferred for me here e.g.

@route('/foo')
def func(request):
return 'bar'

...gets wrapped by maybeDeferred, I can't add an errback to "eat" the deferred

[iffy]

@philmayers does the new handle_errors decorator let you achieve what you want? https://github.com/twisted/klein/blob/master/klein/app.py#L183

[brighid]

No comment from reporter: this probably is safe to close.