/ 
MooX-Role-HasLogger-0.002
River stage zero No dependents
/ MooX::Role::HasLogger

NAME

MooX::Role::HasLogger - Moo role that provides a logger attribute

SYNOPSIS

package Foo;

use Moo;
use MooX::TypeTiny;
use namespace::clean;

with qw( MooX::Role::HasLogger );

sub foo {
  my ( $self ) = @_;
  $self->logger->info( 'log something' );
}

1;

DESCRIPTION

This Moo::Role based role provides a logger attribute to the consuming class. The attribute is read-only and its value is grabbed lazily. The type library MooX::Role::HasLogger::Types exports the Logger type that defines the interface of the attribute. The build_logger() builder method returns a Log::Any logger object with the consuming class as its category.

EXAMPLES

The first example

package Bar;

use Moo;
use MooX::TypeTiny;
use Types::Standard              qw( HasMethods );
use MooX::Role::HasLogger::Types qw( Logger );
use namespace::clean;

with qw( MooX::Role::HasLogger );

has '+logger' => ( isa => ( Logger ) & ( HasMethods [ qw( tracef debugf infof warnf errorf fatalf ) ] ) );

sub build_logger {
  return Log::Any->get_logger( category => ref shift, default_adapter => 'Stderr' );
}

1;

shows

  • how to override the isa option of the logger attribute using the + notation.

  • how to extend the Logger type using a Type::Tiny intersection. Now a logger has to be an object of a class that implements the Logger type methods and additionally the f suffixed log methods.

  • how to override the build_logger() builder method. This time the builder returns a Log::Any logger object with the consuming class as its category and with a default adapter that refers to the Log::Any::Adapter::Stderr adapter class.

As of version 0.002 the previous HasMethods based override of the logger attribute can be replaced with a Type::Tiny::Duck based override

has '+logger' => (
  isa => Type::Tiny::Duck->new(
           name    => 'ExtendedLogger',
           methods => [ \@{ Logger->methods }, qw( tracef debugf infof warnf errorf fatalf ) ]
         )
);

or the new LoggerAny type can be used

use MooX::Role::HasLogger::Types qw( LoggerAny );
has '+logger' => ( isa => LoggerAny );

This new type requires that a logger object has to implement the category() getter method too.

The second example

package Baz;

use Moo;
use MooX::TypeTiny;
use MooX::Role::HasLogger::Types qw( Logger );
use namespace::clean;

with qw( MooX::Role::HasLogger );

has '+logger' => ( handles => Logger->methods );

sub baz {
  my ( $self ) = @_;
  # delegation
  $self->info( 'log something' );
}

1;

shows how to override the handles option of the logger attribute using the + notation. The delegating class Baz can now use the methods provided by the logger (the delegatee) directly. If you prefer to work with an extended interface replace the Logger type with the LoggerAny type.

SEE ALSO

AUTHOR

Sven Willenbuecher <sven.willenbuecher@gmx.de>

COPYRIGHT AND LICENSE

This software is copyright (c) 2023 by Sven Willenbuecher.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.