Re: [log4perl-devel] Change in behavior when upgrading to 1.26 and perl 5.10.0
Mike Schilli wrote:
Thanks for the detailed description, here's what's happening:
This change in behavior was caused by a patch introduced with
Log-Log4perl-1.19 in
http://github.com/mschilli/log4perl/commit/35d86ae53859424ea3ac357eaf0f15d9e69f4bed
in September 2008. A detailed description of the issue at the time is
available in
http://rt.cpan.org/Ticket/Display.html?id=38356
on the request tracker. It fixed problems with the caller_depth, but it
also introduced a change to get_logger() which bumped up the caller()
level to obtain the category (aka package name) of the calling package.
This is probably a good opportunity to rethink how Log4perl wrapper
classes should be implemented.
To implement a L4p wrapper class correctly, it needs to provide the
following four methods:
1 Wrap::get_logger()
2 Wrap::get_logger( $package )
3 Wrap-get_logger()
4 Wrap-get_logger( $package )
Calls #1 and #3 are supposed to obtain a logger with the category of the
calling package, not the category of the wrapper package. This is
especially difficult in case #3, as Log4perl doesn't know if Wrap is
a Log4perl wrapper or if it's the #2 signature where $package is an
application package called Wrap.
Another complication is that we don't know how Wrap is implemented.
Is it relaying the get_logger() call to Log4perl by implementing its own
get_logger function? Or is it simply inheriting from Log4perl?
I've put together a fix to resolve this, please check out the
documentation:
http://github.com/mschilli/log4perl/commit/8ad3fbae60a4667aba848eb545c66339aeff161a
As this might break backward compatibility with earlier versions of
Log4perl, I'm interested in hearing what you think about it, feedback
definitely welcome. If I don't hear anything back, it'll go out with the
next release.
You can play around with the new implementation, here's the tarball:
http://github.com/mschilli/log4perl/tarball/wrapper_fix
Also, I've opened a bug on RT to track this issue:
https://rt.cpan.org/Ticket/Display.html?id=52913
Give it a spin!
-- Mike
Mike Schilli m...@perlmeister.com
Thank you Mike. I've tried this now and it appears to fix the change in
behaviour I reported and does not appear to break anything else I can
see. I am now using the tarball you provided and will report if I see
anything. I will also update the rt later today.
Thanks again
Martin
--
Martin J. Evans
Easysoft Limited
http://www.easysoft.com
On Wed, 9 Dec 2009, Martin Evans wrote:
Mike Schilli wrote:
On Wed, 9 Dec 2009, Martin Evans wrote:
Since the upgrade we are getting no logging in one of the files we
expected to get it. After a bit of searching around I discovered the
module we were using was doing this:
local $Log::Log4perl::caller_depth = $Log::Log4perl::caller_depth + 1;
$h{logger} = Log::Log4perl-get_logger();
and the fix was to change the order of those lines.
Thanks for reporting this, although I have a hard time imaginining how
increasing the caller_depth and then getting a logger would be different
from what you'd get if you did it in the reverse order. Not to mention
that it's puzzling why this would change the logging behavior, as
caller_depth is used mainly for cosmetic reasons in certain features
of the pattern layout.
Can you provide a snippet of code that reproduces the problem in full?
That would really help track down the root of the problem.
Thanks!
-- Mike
Mike Schilli
m...@perlmeister.com
It was ending up with main and the category in the following code
instead of DBIx::Log4perl.
sub get_logger { # Get an instance (shortcut)
##
# get_logger() can be called in the following ways:
#
# (1) Log::Log4perl::get_logger() = ()
# (2) Log::Log4perl-get_logger() = (Log::Log4perl)
# (3) Log::Log4perl::get_logger($cat) = ($cat)
#
# (5) Log::Log4perl-get_logger($cat) = (Log::Log4perl, $cat)
# (6) L4pSubclass-get_logger($cat) = (L4pSubclass, $cat)
# Note that (4) L4pSubclass-get_logger() = (L4pSubclass)
# is indistinguishable from (3) and therefore can't be allowed.
# Wrapper classes always have to specify the category explicitely.
my $category;
if(@_ == 0) {
# 1
$category = scalar caller($Log::Log4perl::caller_depth);
} elsif(@_ == 1) {
# 2, 3
if($_[0] eq __PACKAGE__) {
# 2
$category = scalar caller($Log::Log4perl::caller_depth);
} else {
$category = $_[0];
}
} else {
# 5, 6
$category = $_[1];
}
# Delegate this to the logger module
return Log::Log4perl::Logger-get_logger($category);
}
Here is an example:
1.pl
use Log::Log4perl qw(get_logger :levels);
use DBIx::Log4perl;
Log::Log4perl-init_and_watch('x.conf', 60);
my $a =
Re: [log4perl-devel] Change in behavior when upgrading to 1.26 and perl 5.10.0
Mike Schilli wrote:
Thanks for the detailed description, here's what's happening:
This change in behavior was caused by a patch introduced with
Log-Log4perl-1.19 in
http://github.com/mschilli/log4perl/commit/35d86ae53859424ea3ac357eaf0f15d9e69f4bed
in September 2008. A detailed description of the issue at the time is
available in
http://rt.cpan.org/Ticket/Display.html?id=38356
on the request tracker. It fixed problems with the caller_depth, but it
also introduced a change to get_logger() which bumped up the caller()
level to obtain the category (aka package name) of the calling package.
This is probably a good opportunity to rethink how Log4perl wrapper
classes should be implemented.
To implement a L4p wrapper class correctly, it needs to provide the
following four methods:
1 Wrap::get_logger()
2 Wrap::get_logger( $package )
3 Wrap-get_logger()
4 Wrap-get_logger( $package )
Calls #1 and #3 are supposed to obtain a logger with the category of the
calling package, not the category of the wrapper package. This is
especially difficult in case #3, as Log4perl doesn't know if Wrap is
a Log4perl wrapper or if it's the #2 signature where $package is an
application package called Wrap.
Another complication is that we don't know how Wrap is implemented.
Is it relaying the get_logger() call to Log4perl by implementing its own
get_logger function? Or is it simply inheriting from Log4perl?
I've put together a fix to resolve this, please check out the
documentation:
http://github.com/mschilli/log4perl/commit/8ad3fbae60a4667aba848eb545c66339aeff161a
As this might break backward compatibility with earlier versions of
Log4perl, I'm interested in hearing what you think about it, feedback
definitely welcome. If I don't hear anything back, it'll go out with the
next release.
You can play around with the new implementation, here's the tarball:
http://github.com/mschilli/log4perl/tarball/wrapper_fix
Also, I've opened a bug on RT to track this issue:
https://rt.cpan.org/Ticket/Display.html?id=52913
Give it a spin!
-- Mike
Mike Schilli m...@perlmeister.com
Thanks Mike,
I'm on holiday now and I doubt I'll get a chance to try this properly
until the first week on January - if I do I'll let you know. Hope this
fits in with your timescales - I will try it out as soon as I can.
Martin
On Wed, 9 Dec 2009, Martin Evans wrote:
Mike Schilli wrote:
On Wed, 9 Dec 2009, Martin Evans wrote:
Since the upgrade we are getting no logging in one of the files we
expected to get it. After a bit of searching around I discovered the
module we were using was doing this:
local $Log::Log4perl::caller_depth = $Log::Log4perl::caller_depth + 1;
$h{logger} = Log::Log4perl-get_logger();
and the fix was to change the order of those lines.
Thanks for reporting this, although I have a hard time imaginining how
increasing the caller_depth and then getting a logger would be
different
from what you'd get if you did it in the reverse order. Not to mention
that it's puzzling why this would change the logging behavior, as
caller_depth is used mainly for cosmetic reasons in certain features
of the pattern layout.
Can you provide a snippet of code that reproduces the problem in full?
That would really help track down the root of the problem.
Thanks!
-- Mike
Mike Schilli
m...@perlmeister.com
It was ending up with main and the category in the following code
instead of DBIx::Log4perl.
sub get_logger { # Get an instance (shortcut)
##
# get_logger() can be called in the following ways:
#
# (1) Log::Log4perl::get_logger() = ()
# (2) Log::Log4perl-get_logger() = (Log::Log4perl)
# (3) Log::Log4perl::get_logger($cat) = ($cat)
#
# (5) Log::Log4perl-get_logger($cat) = (Log::Log4perl, $cat)
# (6) L4pSubclass-get_logger($cat) = (L4pSubclass, $cat)
# Note that (4) L4pSubclass-get_logger() = (L4pSubclass)
# is indistinguishable from (3) and therefore can't be allowed.
# Wrapper classes always have to specify the category explicitely.
my $category;
if(@_ == 0) {
# 1
$category = scalar caller($Log::Log4perl::caller_depth);
} elsif(@_ == 1) {
# 2, 3
if($_[0] eq __PACKAGE__) {
# 2
$category = scalar caller($Log::Log4perl::caller_depth);
} else {
$category = $_[0];
}
} else {
# 5, 6
$category = $_[1];
}
# Delegate this to the logger module
return Log::Log4perl::Logger-get_logger($category);
}
Here is an example:
1.pl
use Log::Log4perl qw(get_logger :levels);
use DBIx::Log4perl;
Log::Log4perl-init_and_watch('x.conf', 60);
my $a = DBIx::Log4perl-new();
Log4perl.pm (put this in a dir called DBIx)
===
package DBIx::Log4perl;
sub new
{
local
Re: [log4perl-devel] Change in behavior when upgrading to 1.26 and perl 5.10.0
On Wed, 9 Dec 2009, Martin Evans wrote:
Since the upgrade we are getting no logging in one of the files we
expected to get it. After a bit of searching around I discovered the
module we were using was doing this:
local $Log::Log4perl::caller_depth = $Log::Log4perl::caller_depth + 1;
$h{logger} = Log::Log4perl-get_logger();
and the fix was to change the order of those lines.
Thanks for reporting this, although I have a hard time imaginining how
increasing the caller_depth and then getting a logger would be different
from what you'd get if you did it in the reverse order. Not to mention
that it's puzzling why this would change the logging behavior, as
caller_depth is used mainly for cosmetic reasons in certain features
of the pattern layout.
Can you provide a snippet of code that reproduces the problem in full?
That would really help track down the root of the problem.
Thanks!
-- Mike
Mike Schilli
m...@perlmeister.com
--
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Re: [log4perl-devel] Change in behavior when upgrading to 1.26 and perl 5.10.0
Mike Schilli wrote:
On Wed, 9 Dec 2009, Martin Evans wrote:
Since the upgrade we are getting no logging in one of the files we
expected to get it. After a bit of searching around I discovered the
module we were using was doing this:
local $Log::Log4perl::caller_depth = $Log::Log4perl::caller_depth + 1;
$h{logger} = Log::Log4perl-get_logger();
and the fix was to change the order of those lines.
Thanks for reporting this, although I have a hard time imaginining how
increasing the caller_depth and then getting a logger would be different
from what you'd get if you did it in the reverse order. Not to mention
that it's puzzling why this would change the logging behavior, as
caller_depth is used mainly for cosmetic reasons in certain features
of the pattern layout.
Can you provide a snippet of code that reproduces the problem in full?
That would really help track down the root of the problem.
Thanks!
-- Mike
Mike Schilli
m...@perlmeister.com
It was ending up with main and the category in the following code
instead of DBIx::Log4perl.
sub get_logger { # Get an instance (shortcut)
##
# get_logger() can be called in the following ways:
#
# (1) Log::Log4perl::get_logger() = ()
# (2) Log::Log4perl-get_logger() = (Log::Log4perl)
# (3) Log::Log4perl::get_logger($cat) = ($cat)
#
# (5) Log::Log4perl-get_logger($cat) = (Log::Log4perl, $cat)
# (6) L4pSubclass-get_logger($cat) = (L4pSubclass, $cat)
# Note that (4) L4pSubclass-get_logger() = (L4pSubclass)
# is indistinguishable from (3) and therefore can't be allowed.
# Wrapper classes always have to specify the category explicitely.
my $category;
if(@_ == 0) {
# 1
$category = scalar caller($Log::Log4perl::caller_depth);
} elsif(@_ == 1) {
# 2, 3
if($_[0] eq __PACKAGE__) {
# 2
$category = scalar caller($Log::Log4perl::caller_depth);
} else {
$category = $_[0];
}
} else {
# 5, 6
$category = $_[1];
}
# Delegate this to the logger module
return Log::Log4perl::Logger-get_logger($category);
}
Here is an example:
1.pl
use Log::Log4perl qw(get_logger :levels);
use DBIx::Log4perl;
Log::Log4perl-init_and_watch('x.conf', 60);
my $a = DBIx::Log4perl-new();
Log4perl.pm (put this in a dir called DBIx)
===
package DBIx::Log4perl;
sub new
{
local $Log::Log4perl::caller_depth = $Log::Log4perl::caller_depth + 1;
$h = Log::Log4perl-get_logger();
$h-debug(log msg);
}
1;
x.conf
==
log4perl.logger=ERROR
log4perl.logger.Server = INFO
log4perl.logger.DBIx.Log4perl=DEBUG, X1
log4perl.appender.X1=Log::Log4perl::Appender::File
log4perl.appender.X1.filename=dbix.log
log4perl.appender.X1.mode=append
log4perl.appender.X1.utf8 = 1
log4perl.appender.X1.umask = sub { 0002 }
log4perl.appender.X1.layout=Log::Log4perl::Layout::PatternLayout
log4perl.appender.X1.layout.ConversionPattern=%d %p %F{1}:%L %M - %m%n
then run
perl -I/dir_where_DBIx_dir_is 1.pl
nothing comes out in log. Change the depth after get_logger and it works.
Martin
--
Martin J. Evans
Easysoft Limited
http://www.easysoft.com
--
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Get the facts.
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