Got some problems when using logging Filter

[Vinay Sajip]

On Nov 17, 9:06 am, sword <john... at gmail.com> wrote:
> On Nov 16, 10:50 pm, Peter Otten <__pete... at web.de> wrote:
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> > sword wrote:
> > > Thanks for your reply. I tried to edit the source a bit, now the
> > > main.py looks like this:
> > > #main.py
> > > importlogging
> > > fromloggingimport Filter
> > > import a
> > > import b
>
> > >logging.basicConfig(level=logging.DEBUG)
> > > root =logging.getLogger()
> > > root.addFilter(Filter("GoneWithTheWind")) #so I suppose no log msg
> > > would pass this filter
>
> > > logger =logging.getLogger("main")
> > > logger.debug("main process")
> > > a.print_log()
> > > b.print_log()
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> > > ####
> > > And It still prints out all the log msg. :(
>
> > Here's a little demo to explore how filtering works:
>
> > $ cat demo.py
> > importlogging
> > class Filter(logging.Filter):
> >     def filter(self, record):
> >         print "applying filter", self.name
> >         return True
>
> >logging.basicConfig()
>
> > loggers = [logging.getLogger(path) for path in ["", "a", "a.b"]]
> > for logger in loggers:
> >     logger.addFilter(Filter("filter@" + logger.name))
>
> > [handler] =logging.getLogger().handlers
> > handler.addFilter(Filter("filter at handler"))
>
> > for logger in loggers:
> >     logger.critical("whatever")
> > $ python demo.py
> > applying filter filter at root
> > applying filter filter at handler
> > CRITICAL:root:whatever
> > applying filter filter at a
> > applying filter filter at handler
> > CRITICAL:a:whatever
> > applying filter fil... at a.b
> > applying filter filter at handler
> > CRITICAL:a.b:whatever
> > $
>
> > As you can infer from the output only the filter(s) of the original logger
> > and of the handler(s) are applied.
>
> Thanks, so if I want to see my own log out of all logs produced by
> different module in the project, I should addFilter to each
> corresponding logger. I thought I could add Filter in root and filter
> out only the interested info from it before.

Or you can add a filter to the handler (but then you can't use
basicConfig() to configure it - you need to do it explicitly).

Regards,

Vinay Sajip