log4perl-devel

[log4perl-devel] Re: Fwd: Re: Log::Log4perl::NDC

[Kevin G. <ke...@go...>]

>  but could we also have a Perl API to it? Something like
> 
>     Log::Log4perl->appender_by_name("F1")->
>       layout()->define_placeholder("%K", sub { ... });
> 
> would be great for debuggability. Also, I could hook into that with something like
> 
>     Log::Log4perl->appender_by_name("F1")->
>         add_filter(sub { ... });
> 
> to get a custom filter in later and then I'd be completely happy :).

Mike, after further review, if we do something like this:

   sub Log::Log4perl::appender_by_name {
	return $Log::Log4perl::Logger::APPENDER_BY_NAME{shift};
   }

then we might create problems where the user code has a reference to an
appender, then init_and_watch() reloads everything and the user's
reference is no longer connected to anything, but the user doesn't know
it.  Do you see what I mean?  Do you think this is a problem?


--
Happy Trails. . .

Kevin M. Goess
(and Anne and Frank)
904 Carmel Ave.
Albany, CA  94706
(510)525-5217

[log4perl-devel] Re: Fwd: Re: Log::Log4perl::NDC

[<msc...@ao...>]

In a message dated 11/23/2002 7:08:31 PM Eastern Standard Time, Kevin Goess <ke...@go...> writes:

>Mike, after further review, if we do something like this:
>
>   sub Log::Log4perl::appender_by_name {
>    return $Log::Log4perl::Logger::APPENDER_BY_NAME{shift};
>   }
>
>then we might create problems where the user code has a reference to an
>appender, then init_and_watch() reloads everything and the user's
>reference is no longer connected to anything, but the user doesn't know
>it.

That's an interesting case. Maybe we should have something like the log4j folks: Their appenders can be marked "closed" which allows them to keep them around after a config reload.

Actually, this is a general problem with our implementation -- having a Perl API in parallel with a configuration file which can be reloaded and render any appender references obtained via the Perl API (even as simple as Log::Log4perl::Appender->new()) invalid. This is most likely why the reason the log4j folks have this weird notion of config file reloading, keeping then useless appenders around (but marking them 'closed' I think).

Anyway, I think that it's ok if you put appenders_by_name() in there, it's no worse than Log::Log4perl::Appender->new(). Long term we probably need to re-think the config file reloading, I think I understand now why Ceki did it the way he did it :).

-- Mike

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