Log4Perl across modules

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

Hi,

I have a perl(test.pl) script which creates object for a module (say test.pm) and I use log4perl.pm in test.pl to get logs. My requirement is to add an appender file in test.pm such that two log files are created - one from test.pl and another from test.pm for whatever INFO messages given in both test.pl and test.pm.I use the below code. But what happens is , the log4perl initialisation is replaced by the config given in test.pm and hence only the INFO messages in test.pm gets logged. Is there any way to modify the log4perl configuration in test.pm while it is initialised in test.pl. I just want to have a shared access of Log4perl across modules. Please help.

test.pl --------


use TestModule;

use Log::Log4perl qw(:easy);

my $log_file = "somepath";
my %key_value_pairs = (
    "log4perl.rootLogger"  => "DEBUG, Logfile,TestModule,Screen",
    "log4perl.appender.Logfile"  => "Log::Log4perl::Appender::File",  
+                      
    "log4perl.appender.Logfile.mode"  => "clobber",                   
    "log4perl.appender.Logfile.filename" => "$log_file",              
+  
    "log4perl.appender.Logfile.layout"  => "Log::Log4perl::Layout::Pat
+ternLayout",                 
    "log4perl.appender.Logfile.layout.ConversionPattern" => "%d %p %C:
+%L> %m%n",
    "log4perl.appender.TestModule"   => "Log::Log4perl::Appender::File
+",                       
    "log4perl.appender.TestModule.mode"  => "clobber",                
+   
    "log4perl.appender.TestModule.filename"  => "$log_file",          
+     
    "log4perl.appender.TestModule.layout"  => "Log::Log4perl::Layout::
+PatternLayout",                 
    "log4perl.appender.TestModule.layout.ConversionPattern" => "%d %p 
+%C:%L> %m%n",
    "log4perl.appender.Screen"  => "Log::Log4perl::Appender::Screen", 
+                        
    "log4perl.appender.Screen.layout" => "Log::Log4perl::Layout::Patte
+rnLayout",                   
    "log4perl.appender.Screen.layout.ConversionPattern" => "%d %p %C:%
+L> %m%n",
);

Log::Log4perl::init_once(\%key_value_pairs);

INFO "Creating object for testmodule";

my $testmodule = TestModule->new(
        "key" => "value",
);
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test.pm -------

package TestModule;
use Log::Log4perl qw(:easy);
use strict;
use warnings;

sub new {
    my ($this,%params) = @_;
    
    my $args  = {
        "arg1" => "5",
        "arg2" => "6",
        %params,
    };
    
   bless($args,$this);
   my $log_file = "somepath";
   my $new_log_file = "somefilepath";
  my %key_value_pairs = (
    "log4perl.rootLogger" => "DEBUG, Logfile,TestModule,Screen",
    "log4perl.appender.Logfile"  => "Log::Log4perl::Appender::File",  
+                      
    "log4perl.appender.Logfile.mode"  => "clobber",                   
    "log4perl.appender.Logfile.filename" => "$log_file",              
+  
    "log4perl.appender.Logfile.layout" => "Log::Log4perl::Layout::Patt
+ernLayout",                  
    "log4perl.appender.Logfile.layout.ConversionPattern" => "%d %p %C:
+%L> %m%n",
    "log4perl.appender.TestModule"   => "Log::Log4perl::Appender::File
+",                       
    "log4perl.appender.TestModule.mode"  => "clobber",                
+   
    "log4perl.appender.TestModule.filename"   => "clobber",           
+   
    "log4perl.appender.TestModule.layout" => "Log::Log4perl::Layout::P
+atternLayout",                  
    "log4perl.appender.TestModule.layout.ConversionPattern" => "%d %p 
+%C:%L> %m%n",
    "log4perl.appender.Screen"     => "Log::Log4perl::Appender::Screen
+",                      
    "log4perl.appender.Screen.layout"  => "Log::Log4perl::Layout::Patt
+ernLayout",                  
    "log4perl.appender.Screen.layout.ConversionPattern" => "%d %p %C:%
+L> %m%n", 
);

Log::Log4perl::init(\%key_value_pairs);

   INFO "New object created";
   return $args;
    
}

1;
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Comment on Log4Perl across modules Select or Download Code

Replies are listed 'Best First'.
Re: Log4Perl across modules by McA (Priest) on Sep 13, 2013 at 10:29 UTC
Hi, Log::Log4perl follows the singleton pattern. There is always one instance of that class representing the logging facility. With `init` you initialize it. So, the second init just does what you see, it overwrites the first initialisation. What you want is to add an appender to the initially created object. Therefore you have to look at the runtime methods provides to do that. Have a look at Log::Log4perl::FAQ which gives very much hints how to do it. UPDATE: Have a look at http://search.cpan.org/~mschilli/Log-Log4perl-1.42/lib/Log/Log4perl.pm#Advanced_configuration_within_Perl McA	[reply] [d/l]
Re^2: Log4Perl across modules by rbala (Acolyte) on Sep 13, 2013 at 13:25 UTC
Thanks lot McA!! It seems to work in a test sample. I will proceed integrating it to my code. Thanks, Bala.	[reply]
Re^3: Log4Perl across modules by rbala (Acolyte) on Sep 16, 2013 at 09:05 UTC
Hi, The code works but the issue is even after I add appender file in my module.pm , it is logging only once until it is returned from the subrouting in the module. After that , whatever logging I put, it is appended to only the file , which I appended in script . Below is the code : test.pl ------- use warnings; use strict; use Log::Log4perl qw(:easy); use TestModule; my $log_file = "GIVE SOME PATH"; my %key_value_pairs = ( "log4perl.rootLogger" => "DEBUG, Logfile,TestModule,Screen", "log4perl.appender.Logfile" => "Log::Log4perl::Appender::File", "log4perl.appender.Logfile.mode" => "clobber", "log4perl.appender.Logfile.filename" => "$log_file", "log4perl.appender.Logfile.layout"=> "Log::Log4perl::Layout::Patte +rnLayout", "log4perl.appender.Logfile.layout.ConversionPattern" => "%d %p %C: +%L> %m%n", "log4perl.appender.TestModule" => "Log::Log4perl::Appender::Fi +le", "log4perl.appender.TestModule.mode" => "clobber", "log4perl.appender.TestModule.filename" => "$log_file", "log4perl.appender.TestModule.layout"=> "Log::Log4perl::Layout +::PatternLayout", "log4perl.appender.TestModule.layout.ConversionPattern" => "%d %p +%C:%L> %m%n", "log4perl.appender.Screen" => "Log::Log4perl::Appender::Screen", "log4perl.appender.Screen.layout" => "Log::Log4perl::Layout::Patte +rnLayout", "log4perl.appender.Screen.layout.ConversionPattern" => "%d %p %C: +%L> %m%n", ); Log::Log4perl::init(\%key_value_pairs); my $testmodule = TestModule->new( "key" => "value", ); INFO "Creating object for testmodule"; $testmodule->_printTime(); [download] module.pm --------- `package TestModule; use Log::Log4perl qw(:easy); use strict; use warnings; sub new { my ($this,%params) = @_; my $args = { "arg1" => "5", "arg2" => "6", %params, }; bless($args,$this); my $log_file = "somepath"; my $new_log_file = "GIVE SOME PATH"; my $file_appender = Log::Log4perl::Appender->new( "Log::Log4perl::Appender::File", name => "TestModule", filename => "$new_log_file"); INFO "New object created"; return $args; } sub _printTime { my $time = localtime; INFO "$time"; } 1;` [download] Actually , I need both the files to be updated once a new appender is added.	[reply] [d/l] [select]