log4Perl dynamic filename

[fritz1968]

Hello

I am trying to setup a logging using log4perl where the filename can be set dynamically. Of course I am having troubles. Here is my current code:

my $logFile="$logDir/$logfileName";
$logConf = q(
             log4perl.category.Foo.Bar = INFO, Logfile, Screen
             log4perl.appender.Logfile = log::Log4perl::Appender::File
             log4perl.appender.Logfile.filename = logs/frank.txt
             log4perl.appender.Logfile.layout   = Log::Log4perl::Layou
+t::PatternLayout
            log4perl.appender.Logfile.layout.ConversionPattern = %d   
+  %-25M     %X{logref}     %p     %m %n

             log4perl.appender.Screen         = Log::Log4perl::Appende
+r::Screen
             log4perl.appender.Screen.stderr  = 0
             log4perl.appender.Screen.layout = Log::Log4perl::Layout::
+SimpleLayout
  );
        Log::Log4perl->init(\$logConf);

The problem is that I don't want each file name to be named "logs/frank.txt". I would rather have something like:

logs/frank.<date>.txt

Any help would be greatly appreciated.
Thanks,
Frank

[stefbv]

Use a sub reference function to return the file name, like this:

log4perl.appender.Logfile.filename = sub { get_log_filename(); }

Regards, Stefan

Updated.

[Anonymous Monk]

This is FAQ

Re: Can I from within a module access variables from the calling program?

Q: What if I need dynamic values in a static Log4perl configuration file?

A: log4perl.appender.Logfile.filename = sub { logfile(); };

A: log4perl.appender.Logfile.filename = sub { MyHackySack->logfile(); };

A: log4perl.appender.Logfile.filename = sub { $Hallo::Ween::GLOBULON || 'punkinguts.log' };

[dd-b]

I do it like this:

use Log::Log4perl;
my $logfile = 'clean.log';
unlink $logfile;        # ignore errors
do {                # Isolate
    # Log configuration.
    # If you go for interpolation, escape the {} in the pattern or use
    # different delimiters or something.
    my $lconf = q{
    log4perl.logger = TRACE, ap1
    log4perl.appender.ap1 = Log::Log4perl::Appender::File
    log4perl.appender.ap1.filename = } . $logfile . q'
    log4perl.appender.ap1.layout = Log::Log4perl::Layout::PatternLayou
+t
    log4perl.appender.ap1.layout.ConversionPattern = %d{yyyyMMdd HH:mm
+:ss.SSSS} %5p %F{1} %L: %m %n
        log4perl.appender.ap2 = Log::Log4perl::Appender::Screen
        log4perl.appender.ap2.layout = Log::Log4perl::Layout::PatternL
+ayout
        log4perl.appender.ap2.layout.ConversionPattern = %d{yyyyMMdd H
+H:mm:ss.SSSS} %5p %F{1} %L: %m %n
    ';
    # unclear, but this MIGHT mean something.
    Log::Log4perl::init ( \$lconf ) or die "Log init failed";
};                # Isolate
my $logger = Log::Log4perl->get_logger('Test');

That is, by using substitution within the quoted string config.

You could also do it using function-call config, and possibly by doing a string config and then overriding that one thing with a function call, I believe, but I haven't done that, so I won't give you fake example code.

[Anonymous Monk]

Hello fritz1968, I personally prefer to use config files for configuration purposes, so I have a file pllog.conf:

log4perl.rootLogger = TRACE, FileApp, XMLAppender, ScreenApp
log4perl.appender.FileApp = Log::Log4perl::Appender::File
log4perl.appender.FileApp.filename = sub { my $Me=$0; $Me =~ s/^.*\\//
+; $Me =~ s/\..*//; return "$Me.log" }
log4perl.appender.FileApp.layout = PatternLayout
log4perl.appender.FileApp.layout.ConversionPattern   = %d{ISO8601} (%-
+13F: %04L) %m%n

And somewhere in perl code:

    use Log::Log4perl qw(get_logger);
    Log::Log4perl->init("pllog.conf");
    my $logger = get_logger("My_Tools.$Me");

Used in this way, you get a logfile with the same name as your perl file but with .log instead of .pl. I only showed the file appender path, as you requsted. You can change this approach easily to fit your needs. And you can change the whole log4perl thing without changing your code.

[periapt]

For many projects, I like to define a simple functional logging configuration.

sub InitLogger {
    my $logfile = shift;

    my $logconf = q|
        log4perl.logger.[package_name]                     = INFO, Log
+File
        log4perl.appender.LogFile             = Log::Log4perl::Appende
+r::File
        log4perl.appender.LogFile.filename                 = LOGFILE
        log4perl.appender.LOG.mode                         = append
        log4perl.appender.LogFile.layout                   = PatternLa
+yout
        log4perl.appender.LogFile.layout.ConversionPattern = %d %5p> %
+m%n
       |;

    $logconf =~ s/LOGFILE/$logfile/;

    Log::Log4perl->init( \$logconf );

    return Log::Log4perl::get_logger("[package_name");
}    # end InitLogger();

I set the log4perl.appender.LogFile.filename option to an arbitrary value 'LOGNAME' so that I can replace it in the string later. Not sure why but I've found this to be more stable than using variable substitution inside the config string itself.

If my projects grows to encompass several program files with almost identical log specs (except maybe for filename), I can pull the function into a library and share