log4perl-devel

[log4perl-devel] Can caller_depth be set per logger

[Martin J. E. <mar...@ea...>]

Hi,

I mailed this question some months ago and did not get any response so I 
thought I'd have one last go slightly reworded.

I have many different loggers in the same application in the program 
itself and various modules. One module is a wrapper class around DBI and 
has to set the caller_depth to 2 but caller_depth seems to be global and 
hence this affects all other loggers in the same program. Is there any 
way to set caller_depth per logger?

My precise example was in my post on this list 3-dec-07.

Thanks

Martin
-- 
Martin J. Evans
Easysoft Limited
http://www.easysoft.com

Re: [log4perl-devel] Can caller_depth be set per logger

[Kevin M. G. <cp...@go...>]

Martin,

Have you tried something like this?  It would go in each wrapper method
in your st.pm and db.pm, at the beginning of the method:

	local $Log::Log4perl::caller_depth =
                   $Log::Log4perl::caller_depth + 2;

It's a package variable, so no, there is no other way to set it per-logger.

There's some discussion of this in the FAQ ("perldoc Log::Log4perl::FAQ").




Martin J. Evans wrote:
> Hi,
> 
> I mailed this question some months ago and did not get any response so I 
> thought I'd have one last go slightly reworded.
> 
> I have many different loggers in the same application in the program 
> itself and various modules. One module is a wrapper class around DBI and 
> has to set the caller_depth to 2 but caller_depth seems to be global and 
> hence this affects all other loggers in the same program. Is there any 
> way to set caller_depth per logger?
> 
> My precise example was in my post on this list 3-dec-07.
> 
> Thanks
> 
> Martin

Re: [log4perl-devel] Can caller_depth be set per logger

[Martin E. <mar...@ea...>]

Thanks for the reply Kevin.

Kevin M. Goess wrote:
> Martin,
> 
> Have you tried something like this?  It would go in each wrapper method
> in your st.pm and db.pm, at the beginning of the method:
> 
> 	local $Log::Log4perl::caller_depth =
>                    $Log::Log4perl::caller_depth + 2;

I should have said I knew I could do this but a) there are an awful lot 
of methods b) when logging is not enabled each method has the overhead 
of the above statement for nothing.

> It's a package variable, so no, there is no other way to set it per-logger.

Shame.

> There's some discussion of this in the FAQ ("perldoc Log::Log4perl::FAQ").

I haven't yet looked at the code - do you know how difficult it would be 
to make caller_depth per logger?

Martin
-- 
Martin J. Evans
Easysoft Limited
http://www.easysoft.com

> Martin J. Evans wrote:
>> Hi,
>>
>> I mailed this question some months ago and did not get any response so I 
>> thought I'd have one last go slightly reworded.
>>
>> I have many different loggers in the same application in the program 
>> itself and various modules. One module is a wrapper class around DBI and 
>> has to set the caller_depth to 2 but caller_depth seems to be global and 
>> hence this affects all other loggers in the same program. Is there any 
>> way to set caller_depth per logger?
>>
>> My precise example was in my post on this list 3-dec-07.
>>
>> Thanks
>>
>> Martin
> 
> 

Re: [log4perl-devel] Can caller_depth be set per logger

[Kevin M. G. <cp...@go...>]

>> 	local $Log::Log4perl::caller_depth =
>>                    $Log::Log4perl::caller_depth + 2;
>
> I should have said I knew I could do this but a) there
> are an awful lot of methods b) when logging is not
> enabled each method has the overhead of the above
> statement for nothing.

Well, that's true, but the overhead is dwarfed by what it's already
costing you to subclass the DBI methods.  On my box I can process
196,002 child-method calls per second, and that decreases to 176,991
calls per second when adding the manipulation of $caller_depth.  On the
other hand, calling the parent method would have run at 1,689,189 per
second.

And you could probably improve the performance of manipulating
$caller_depth by skipping it unless $h->{logger}->is_debug is true.

call_local:  3 wallclock secs ( 1.92 usr +  0.00 sys =  1.92 CPU) @
2604166.67/s (n=5000000)
child_with_local: 29 wallclock secs (28.19 usr +  0.06 sys = 28.25 CPU)
@ 176991.15/s (n=5000000)
childmethod: 26 wallclock secs (25.47 usr +  0.04 sys = 25.51 CPU) @
196001.57/s (n=5000000)
supermethod:  3 wallclock secs ( 2.95 usr +  0.01 sys =  2.96 CPU) @
1689189.19/s (n=5000000)

----------------
use strict;
use Benchmark;

$Log::Log4perl::caller_depth = 0;

{ package testpackage;
  sub runmethod {}
}

{ package child::testpackage;
  push our @ISA, 'testpackage';
  sub runmethod {
     my($sth, @args) = @_;
     my $h = $sth->{private_DBIx_Log4perl};
     my $res = $sth->SUPER::runmethod(@args);
  }
  #the same thing, but with a local() call added
  sub runmethod_with_local {
     my($sth, @args) = @_;
     local $Log::Log4perl::caller_depth =
                    $Log::Log4perl::caller_depth + 2
        if ;
     my $h = $sth->{private_DBIx_Log4perl};
     my $res = $sth->SUPER::runmethod(@args);
  }
}

my $dbh = {};
bless $dbh, 'testpackage';
my $dbhX = {private_DBIX_Log4perl => 1};
bless $dbhX, 'child::testpackage';


my @args = (1,2,3);
timethese( 5000000, {
    supermethod =>      sub { $dbh->runmethod(@args) },
    childmethod =>      sub { $dbhX->runmethod(@args) },
    child_with_local => sub { $dbhX->runmethod_with_local(@args) },
    call_local =>      sub { local $Log::Log4perl::caller_depth =
                    $Log::Log4perl::caller_depth + 2; },

});