Log::Declare - A high performance Perl logging module


Creates syntactic sugar for logging using categories with sprintf support.

Complex logging statements can be written without impacting on performance when those log levels are disabled.

For example, using a typical logger, this would incur a penalty even if the logging is disabled:

    $self->log(Dumper $myobject);

but with Log::Declare we incur almost no performance penalty if 'info' level is disabled, since the following log statement:

    info Dumper $myobject [mycategory];

gets rewritten as:

    info && $Log::Declare::logger->log('info', ['mycategory'], Dumper $myobject);

which means if 'info' returns 0, nothing else gets evaluated.


    use Log::Declare;
    use Log::Declare qw/ :nosyntax /; # disables syntactic sugar
    use Log::Declare qw/ :nowarn :noerror ... /; # disables specific sugar

    # with syntactic sugar
    debug "My debug message" [category];
    error "My error message: %s", $error [category1, category2];

    # auto-dump variables with Data::Dumper
    debug "Using sprintf format: %s", d:$error [category];

    # auto-ref variables with ref()
    debug "Using sprintf format: %s", r:$error [category];

    # capture other loggers (loses Log::Declare performance)
    Log::Declare->capture('Test::Logger::log' => sub {
        my ($logger, @args) = @_;
        # manipulate logger args here
        return @args;


If you're using a namespace-aware logger, Log::Declare can use your logger's namespacing to determine log levels. For example:

    $Log::Declare::levels{'debug'} = sub {