[log4perl-devel] RE: Log::Log4perl::Layout::PatternLayout

[Armaity.Bilimoria <Arm...@ta...>]

Mike,
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Sounds good, we could use the customized caller() function.
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Thank you,
Armaity

	-----Original Message-----
	From: Mike Schilli [mailto:msc...@ao...]=20
	Sent: Sunday, December 07, 2003 1:52 AM
	To: Armaity.Bilimoria
	Cc: m...@pe...; log4perl-devel
	Subject: RE: Log::Log4perl::Layout::PatternLayout
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	Armaity.Bilimoria wrote on 12/3/2003, 7:32 AM:=20

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		We have two levels of sub classing - A.pm is a subclass
of Log::Log4perl::Layout::PatternLayout and in this module we have
specified different layouts we need to work with. These layouts include
%d, %F, %L, %M and many other placeholders and are used for all our logs
and A.pm has been doing just fine for almost a year now.
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		This is the first time we are creating logs from the
Database and we want to leverage the code in A.pm, so we thought of
creating a subclass of A.pm named B.pm where we could use the same
layouts but=20
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		1. pass the %d placeholder the time from the database
instead of the default current_time it picks up.

	We got that one fixed. One down, two to go.
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		2. pass '' for %F %L %M and other placeholders we do not
have information for in the database.=20
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		3. pass a constant value to MDC only for the set of logs
from the database.
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		Unfortunately the only way we thought we could
accomplish that was by overriding what gets passed to these placeholders
current_time() for %d, curly_action() for %X{progname} and render() for
other placeholders, in this new Module.

	I think overriding %X{progname} wasn't necessary, setting the
MDC in your program reading out the database records should have
accomplished what you needed.
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	Overriding render() is a bit problematic, because in order to do
so you must have copied a chunk of code. Hmm, so what to do about %F and
%L ... you could set the Log::Log4perl::caller_depth to a high value and
get [undef] for all of them, but that's just awful. Another option would
be for PatternLayout to allow a customized caller() function. How's
that?
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	--=20
	-- Mike
	Mike Schilli
	m...@pe...=20