[SCM] libmessage-passing-perl Debian packaging branch, master, updated. debian/0.111-3-14-g44f6e88

[Tomas Doran]

The following commit has been merged in the master branch:
commit a0bcb41427d6a5b308d8df7755f80a1598e0a4db
Author: Tomas Doran <bobtfish at bobtfish.net>
Date:   Sun Aug 26 10:03:22 2012 +0100

    Make error chains more useful

diff --git a/Changes b/Changes
index 26f999f..89b6e5a 100644
--- a/Changes
+++ b/Changes
@@ -1,3 +1,9 @@
+  - Add error chain support to the JSON encoder so that an error is
+    logged if JSON encoding fails.
+
+  - Make default error chain do JSON encoding on errors so that they're
+    readable.
+
 0.101
   - Fix daemonization features provided by Message::Passing::Role::Script
     to work on the command line again by exlicitly using MooX::Options
diff --git a/lib/Message/Passing/Filter/Encoder/JSON.pm b/lib/Message/Passing/Filter/Encoder/JSON.pm
index 956b980..3980775 100644
--- a/lib/Message/Passing/Filter/Encoder/JSON.pm
+++ b/lib/Message/Passing/Filter/Encoder/JSON.pm
@@ -3,9 +3,14 @@ use Moo;
 use MooX::Types::MooseLike::Base qw/ Bool /;
 use JSON qw/ to_json /;
 use Scalar::Util qw/ blessed /;
+use Try::Tiny;
+use Data::Dumper ();
 use namespace::clean -except => 'meta';
 
-with 'Message::Passing::Role::Filter';
+with qw/
+    Message::Passing::Role::Filter
+    Message::Passing::Role::HasErrorChain
+/;
 
 has pretty => (
     isa => Bool,
@@ -15,19 +20,28 @@ has pretty => (
 
 sub filter {
     my ($self, $message) = @_;
-    return $message unless ref($message);
-    if (blessed $message) { # FIXME - This should be moved out of here!
-        if ($message->can('pack')) {
-            $message = $message->pack;
-        }
-        elsif ($message->can('to_hash')) {
-            $message = $message->to_hash;
+    try {
+        return $message unless ref($message);
+        if (blessed $message) { # FIXME - This should be moved out of here!
+            if ($message->can('pack')) {
+                $message = $message->pack;
+            }
+            elsif ($message->can('to_hash')) {
+                $message = $message->to_hash;
+            }
         }
+        to_json( $message, { utf8  => 1, $self->pretty ? (pretty => 1) : () } )
+    }
+    catch {
+        $self->error->consume({
+            class => 'Message::Passing::Exception::Encoding',
+            exception => $_,
+            stringified_data => Data::Dumper::Dumper($message),
+        });
+        return; # Explicitly drop the message from normal processing
     }
-    to_json( $message, { utf8  => 1, $self->pretty ? (pretty => 1) : () } )
 }
 
-
 1;
 
 =head1 NAME
@@ -82,4 +96,5 @@ the SureVoIP API -
 
 See L<Message::Passing>.
 
-=cut
\ No newline at end of file
+=cut
+
diff --git a/lib/Message/Passing/Role/HasErrorChain.pm b/lib/Message/Passing/Role/HasErrorChain.pm
index 84907ef..3b807d6 100644
--- a/lib/Message/Passing/Role/HasErrorChain.pm
+++ b/lib/Message/Passing/Role/HasErrorChain.pm
@@ -1,13 +1,18 @@
 package Message::Passing::Role::HasErrorChain;
 use Moo::Role;
-use Message::Passing::Output::STDERR;
+use Module::Runtime qw/ require_module /;
 use namespace::clean -except => 'meta';
 
 has error => (
     is => 'ro',
     default => sub {
-        Message::Passing::Output::STDERR->new;
+        require_module 'Message::Passing::Output::STDERR';
+        require_module 'Message::Passing::Filter::Encoder::JSON';
+        Message::Passing::Filter::Encoder::JSON->new(
+            output_to => Message::Passing::Output::STDERR->new,
+        );
     },
+    lazy => 1,
 );
 
 1;
@@ -43,16 +48,44 @@ Some components can create an error stream in addition to a message stream.
 
 An attribute containing the error chain.
 
+By default, this is a chain of:
+
+=over
+
+=item Message::Passing::Filter::Encoder::JSON
+
+=item Message::Passing::Output::STDOUT
+
+=back
+
+=head1 WARNINGS
+
+=head2 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.
+
+=head2 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.
+
 =head1 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 - 
+the SureVoIP API -
 <http://www.surevoip.co.uk/support/wiki/api_documentation>
 
 =head1 AUTHOR, COPYRIGHT AND LICENSE
 
 See L<Message::Passing>.
 
-=cut
\ No newline at end of file
+=cut
+

-- 
libmessage-passing-perl Debian packaging