NAME

       Bread::Board::Manual::Example::LogDispatch - An example of composing a dynamic
       Log::Dispatch object.

VERSION

       version 0.37

SYNOPSIS

         my $c = container 'Logging' => as {
             service 'Logger' => (
                 block => sub {
                     my $s       = shift;
                     my $c       = $s->parent;
                     my $outputs = $c->get_sub_container('Outputs');
                     my $log     = Log::Dispatch->new;
                     foreach my $name ( $outputs->get_service_list ) {
                         $log->add(
                             $outputs->get_service( $name )->get
                         );
                     }
                     $log;
                 }
             );

             container 'Outputs' => as {
                 service 'File' => (
                     block => sub {
                         Log::Dispatch::File->new(
                             name      => 'file',
                             min_level => 'debug',
                             filename  => 'logfile'
                         )
                     }
                 );
                 service 'Screen' => (
                     block => sub {
                         Log::Dispatch::Screen->new(
                             name      => 'screen',
                             min_level => 'warning',
                         )
                     }
                 );
             };
         };

         my $logger = $c->resolve( service => 'Logging/Logger' );

DESCRIPTION

       This example was inspired by a discussion I had with Jay Shirley.  He wanted to know an
       easy way to have a dynamic list of output types for his Log::Dispatch object.

       Often with Bread::Board you will be wiring up components that are of a fixed type and set,
       but this is not always the case.  It is in these cases when you can simply use the
       Bread::Board objects themselves to fetch your dependencies.

       The value passed into the block of a BlockInjection service is the service itself. Calling
       the "parent" method on that service will give you the container that service is in. From
       there you can introspect the other containers and services any which way you want to.

       This example can be made even more dynamic if you build the 'Logging' component as a
       parameterized container whose parameter is the 'Outputs' container. Here is what that
       would look like.

         my $logging = container 'Logging' => [ 'Outputs' ] => as {
             service 'Logger' => (
                 block => sub {
                     my $s       = shift;
                     my $c       = $s->parent;
                     my $outputs = $c->get_sub_container('Outputs');
                     my $log     = Log::Dispatch->new;
                     foreach my $name ( $outputs->get_service_list ) {
                         $log->add(
                             $outputs->get_service( $name )->get
                         );
                     }
                     $log;
                 }
             );
         };

         my $outputs = container 'Outputs' => as {
             service 'File' => (
                 block => sub {
                     Log::Dispatch::File->new(
                         name      => 'file',
                         min_level => 'debug',
                         filename  => 'logfile'
                     )
                 }
             );
             service 'Screen' => (
                 block => sub {
                     Log::Dispatch::Screen->new(
                         name      => 'screen',
                         min_level => 'warning',
                     )
                 }
             );
         };

         my $c  = $logging->create( Outputs => $outputs );
         my $ld = $c->resolve( service => 'Logging/Logger' );

       This example illustrates how when a parameterized container is instantiated, the
       parameters become sub-containers of the resulting container. This makes it just as easy to
       fetch the 'Outputs' container and use it inside the 'Logger' service.

AUTHOR

       Stevan Little <stevan@iinteractive.com>

BUGS

       Please report any bugs or feature requests on the bugtracker website
       https://github.com/stevan/BreadBoard/issues

       When submitting a bug or request, please include a test-file or a patch to an existing
       test-file that illustrates the bug or desired feature.

COPYRIGHT AND LICENSE

       This software is copyright (c) 2019, 2017, 2016, 2015, 2014, 2013, 2011, 2009 by Infinity
       Interactive.

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

perl v5.36.0                                2022-1Bread::Board::Manual::Example::LogDispatch(3pm)