GB has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I'm trying to use log4perl and I want to log in a module which is called from multiple different script files. Irrespective of who the caller is, the module should log the message to that particular callers adapter/log file. Can this be achieved?


I'm trying to do the following.
test.pl 
my $conf = q(                                                         
+                                  
            log4perl.logger.testLog = ).$logging_level.q(, logApp
            log4perl.appender.logApp= Log::Log4perl::Appender::File   
+      
            log4perl.appender.logApp.mode= append
            log4perl.appender.logApp.syswrite= 1
            log4perl.appender.logApp.filename= test.log               
+       
            log4perl.appender.logApp.layout= Log::Log4perl::Layout::Pa
+tternLayout 
            log4perl.appender.logApp.layout.ConversionPattern   = %m %
+n
       )
Log::Log4perl->init( \$conf );                                        
+                                  
use testPackage;                                                      
+                                  
&testPackage::foo();

[download]
testPackage.pm 
package testPackage;

use Log::Log4perl qw(get_logger);
sub foo {
    $logger = Log::Log4perl->get_logger("");  # IF I PUT testLog IN TH
+E QUOTES THEN I'M GETTING THE blah IN THE CALLERS LOGS FILE
    $logger->info("blah");
}
1;

[download]
Can some monks please see this and bestow the light on this.

Replies are listed 'Best First'.
Re: log4perl in module appending to callers log file
by Khen1950fx (Canon) on Jul 28, 2011 at 04:21 UTC
    You were trying to go by the example in the doc, but you went a little too far afield. I fixed it up for you, but I can't really see what the problem is that you're having. 
    #!/usr/bin/perl

use strict;
use warnings;
use Log::Log4perl qw(get_logger);

my $conf = q(                                                         
+                            
    log4perl.category.testLog  = INFO, logApp
    log4perl.appender.logApp   = Log::Log4perl::Appender::File        
+ 
    log4perl.appender.logApp.mode     = append
    log4perl.appender.logApp.filename = test.log                      
    log4perl.appender.logApp.layout   = \
        Log::Log4perl::Layout::PatternLayout 
    log4perl.appender.logApp.layout.ConversionPattern - %m%n
);

Log::Log4perl::init(\$conf);

my $logger = get_logger('testLog');
$logger->error('This is better!');

    [download]
[reply]
[d/l]
Re: log4perl in module appending to callers log file
by wwe (Friar) on Jul 28, 2011 at 13:22 UTC
    may be you are missing to call get_logger in the main script. try this one: 
    use strict;
use warnings;
use Log::Log4perl;

my $logging_level = 'DEBUG';

my $conf = q(                                                         
+                                  
            log4perl.rootLogger = ).$logging_level.q(, logApp
            
            log4perl.appender.logApp = Log::Log4perl::Appender::File  
+       
            log4perl.appender.logApp.mode = append
            log4perl.appender.logApp.filename = 917173_test.log       
+               
            log4perl.appender.logApp.layout = Log::Log4perl::Layout::P
+atternLayout 
            log4perl.appender.logApp.layout.ConversionPattern   = %m %
+n
       );
       
Log::Log4perl->init( \$conf );                                        
+                                  
my $logger = Log::Log4perl->get_logger(); 
$logger->info("outer");
testPackage::foo(); 
$logger->info("outer");

package testPackage;

use Log::Log4perl qw(get_logger);
sub foo {
    my $logger = Log::Log4perl->get_logger();  # IF I PUT testLog IN T
+HE QUOTES THEN I'M GETTING THE blah IN THE CALLERS LOGS FILE
    $logger->info("inner");
}
1;

    [download]
    this produces following output: 
    outer 
inner 
outer

    [download]
[reply]
[d/l]
[select]
      Thanks for the reply. I wanted this behavior where called module logs to the caller script's appenders. The only logical difference I see from your code is that you have used rootLogger and I've used my logger.testLog. I'm also calling get_logger in the module but looks like calling get_logger("") in the module writes to rootLogger and not custom logger.

      And so I was not able to get the logs from the called module into the caller appenders.

      Do you know if there is any other way If I don't use the rootLogger and also doesn't specify the target logger name in the called module?
[reply]
        I'm not a guru but this is a way I used Log4Perl. I don't know a reference but I think there is a logging hierarchy in other words there is a parent logger where all other logger depend on. And the logger on the top is a root logger. Maybe called modules look for this specific logger where they can append to. This config works fine for me so I don't care much about the thing behind it...
[reply]

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