On Thu, Dec 9, 2010 at 12:27 AM, Antoine Pitrou <solip...@pitrou.net> wrote: > On Wed, 8 Dec 2010 12:15:53 +0000 (UTC) > Vinay Sajip <vinay_sa...@yahoo.co.uk> wrote: >> See my comments to Nick Coghlan's post about getting messages out when you >> can't >> raise an exception. I think the case is not as common as you suggest >> (because in >> many instances, you would raise an exception to signal an error). > > I'm not talking specifically about exceptions, but about errors in > general. If the case wasn't common, I'm not sure why the error() and > critical() methods would exist at all. > > (of course I'm assuming error() is meant to output error messages. If > that's a wrong interpretation then I'm a bit puzzled :-))
As I see it, there aren't many cases at the *library* level where logging errors is more appropriate than raising exceptions: - operations where there is no outer exception handler, and the library knows it (e.g. callback processing) - methods that are guaranteed not to raise exceptions (e.g. top level event handlers) Some batch processing operations may also work that way, but those are a little more questionable (it may be better to report a result summary and leave it up to the application to decide what to do with any errors encountered along the way) However, it *is* the case that logging is currently ill-suited to tasks that are otherwise handled by writing directly to sys.stderr. I suspect that has influenced some people's views of its suitability for use in published libraries, even though it doesn't actually affect most libraries (I suspect it is a significant chunk of what underlay my reservations about using logging in library code). Since the standard library *does* include modules that currently write to stderr, then adjusting logging to make it better suited to this task will help us as well as anyone else with similar problems. That said, while I think Vinay's suggested "handler of last resort" solution is a good one and something we should be doing for 3.2, I'm also happy to let the idea bake for at least a few weeks. Cheers, Nick. P.S. On a completely unrelated note, has anyone thought about creating a write-only TextIO stream that outputs received writes via the logging module? -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
