etc/log4perl.conf:

log4perl.logger.intranet = WARN, INTRANET
log4perl.appender.INTRANET=Log::Log4perl::Appender::File
log4perl.appender.INTRANET.filename=/home/koha/koha-dev/var/log/intranet-error.log
log4perl.appender.INTRANET.mode=append
log4perl.appender.INTRANET.layout=PatternLayout
log4perl.appender.INTRANET.layout.ConversionPattern=[%d] [%p] %m %l %n
log4perl.logger.opac = WARN, OPAC
log4perl.appender.OPAC=Log::Log4perl::Appender::File
log4perl.appender.OPAC.filename=/home/koha/koha-dev/var/log/opac-error.log
log4perl.appender.OPAC.mode=append
log4perl.appender.OPAC.layout=PatternLayout
log4perl.appender.OPAC.layout.ConversionPattern=[%d] [%p] %m %l %n```

The module I want to do logging:

use Koha::Logger;
[...]
    my $self  = {
        ua          => LWP::UserAgent->new,
        config      => $config,
        logger      => Koha::Logger->get(
            { category => 'Koha.Illbackends.BLDSS.BLDSS.API' }
        )
    };
[...]
$self->{logger}->info( "Hellloooooooooo" );