NAME

       Message::Passing::Role::HasErrorChain - A role for components which can report errors

SYNOPSIS

           # Note this is an example package, and does not really exist!
           package Message::Passing::Output::ErrorAllMessages;
           use Moo;
           use namespace::clean -except => 'meta';

           with qw/
               Message::Passing::Role::Output
               Message::Passing::Role::HasErrorChain
           /;

           sub consume {
               my ($self, $message) = @_;
               $self->error->consume($message);
           }

DESCRIPTION

       Some components can create an error stream in addition to a message stream.

METHODS

   error
       An attribute containing the error chain.

       By default, this is a chain of:

       Message::Passing::Filter::Encoder::JSON
       Message::Passing::Output::STDOUT

WARNINGS

   ERROR CHAINS CAN LOOP
       If you override the error chain output, be sure that the error chain does not go into your
       normal log path! This is because if you suddenly have errors in your normal log path, and
       you then start logging these errors, this causes more errors - causing you to generate a
       message loop.

   ENCODING IN ERROR CHAINS
       If you emit something which cannot be encoded to an error chain then the encoding error
       will likely be emitted by the error chain - this can again cause loops and other issues.

       All components which use error chains should be very careful to output data which they are
       entirely certain will be able to be encoded.

SPONSORSHIP

       This module exists due to the wonderful people at Suretec Systems Ltd.
       <http://www.suretecsystems.com/> who sponsored its development for its VoIP division
       called SureVoIP <http://www.surevoip.co.uk/> for use with the SureVoIP API -
       <http://www.surevoip.co.uk/support/wiki/api_documentation>

AUTHOR, COPYRIGHT AND LICENSE

       See Message::Passing.