NAME¶
Message::Passing - a simple way of doing messaging.
SYNOPSIS¶
message-pass --input STDIN --output STDOUT
{"foo": "bar"}
{"foo":"bar"}
DESCRIPTION¶
A library for building high performance, loosely coupled and reliable/resilient
applications, structured as small services which communicate over the network
by passing messages.
BASIC PREMISE¶
You have data for discrete events, represented by a hash (and serialized as
JSON).
This could be a text log line, an audit record of an API event, a metric emitted
from your application that you wish to aggregate and process - anything that
can be a simple hash really..
You want to be able to shove these events over the network easily, and aggregate
them / filter and rewrite them / split them into worker queues.
This module is designed as a simple framework for writing components that let
you do all of these things, in a simple and easily extensible manor.
For a practical example, You generate events from a source (e.g. ZeroMQ output
of logs and performance metrics from your Catalyst FCGI or Starman workers)
and run one script that will give you a central application log file, or push
the logs into ElasticSearch.
There are a growing set of components you can plug together to make your
solution.
Getting started is really easy - you can just use the
"message-passing" command installed by the distribution. If you have
a common config that you want to repeat, or you want to write your own server
which does something more flexible than the normal script allows, then see
Message::Passing::DSL.
To dive straight in, see the documentation for the command line utility
message-passing, and see the examples in Message::Passing::Manual::Cookbook.
For more about how the system works, see Message::Passing::Manual::Concepts.
COMPONENTS¶
Below is a non-exhaustive list of components available.
Inputs receive data from a source (usually a network protocol).
They are responsible for decoding the data into a hash before passing it onto
the next stage.
Inputs include:
- Message::Passing::Input::STDIN
- Message::Passing::Input::ZeroMQ
- Message::Passing::Input::STOMP
- Message::Passing::Input::AMQP
- Message::Passing::Input::Syslog
- Message::Passing::Input::Redis
- Message::Passing::Input::Test
You can easily write your own input, just use AnyEvent, and consume
Message::Passing::Role::Input.
FILTER¶
Filters can transform a message in any way.
Examples include:
- Message::Passing::Filter::Null - Returns the input unchanged.
- Message::Passing::Filter::All - Stops any messages it receives from being
passed to the output. I.e. literally filters all input out.
- Message::Passing::Filter::T - Splits the incoming message to multiple
outputs.
You can easily write your own filter, just consume
Message::Passing::Role::Filter.
Note that filters can be chained, and a filter can return undef to stop a
message being passed to the output.
OUTPUTS¶
Outputs send data to somewhere, i.e. they consume messages.
- Message::Passing::Output::STDOUT
- Message::Passing::Output::AMQP
- Message::Passing::Output::STOMP
- Message::Passing::Output::ZeroMQ
- Message::Passing::Output::WebHooks
- Message::Passing::Output::ElasticSearch -
(<https://github.com/suretec/Message-Passing-Output-ElasticSearch>)
- Message::Passing::Output::Redis
- Message::Passing::Output::Test
SEE ALSO¶
- Message::Passing::Manual - The manual (contributions cherished)
- <http://www.slideshare.net/bobtfish/messaging-interoperability-and-log-aggregation-a-new-framework>
- Slide deck!
- Log::Message::Structured - For creating your log messages.
- Log::Dispatch::Message::Passing - use Message::Passing outputs from
Log::Dispatch.
THIS MODULE¶
This is a simple MooX::Options script, with one input, one filter and one
output. To build your own similar scripts, see:
- Message::Passing::DSL - To declare your message chains
- Message::Passing::Role::CLIComponent - To provide "foo" and
"foo_options" attribute pairs.
- Message::Passing::Role::Script - To provide daemonization features.
METHODS¶
build_chain
Builds and returns the configured chain of input => filter => output
start
Class method to call the run_message_server function with the results of having
constructed an instance of this class, parsed command line options and
constructed a chain.
This is the entry point for the script.
AUTHOR¶
Tomas (t0m) Doran <bobtfish@bobtfish.net>
SUPPORT¶
Bugs¶
Please log bugs at rt.cpan.org. Each distribution has a bug tracker link in it's
metacpan.org page.
Discussion¶
#message-passing on irc.perl.org.
Source code¶
Source code for all modules is available at <
http://github.com/suretec>
and forks / patches are very welcome.
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>
COPYRIGHT¶
Copyright Suretec Systems Ltd. 2012.
Logstash (upon which many ideas for this project is based, but which we do not
reuse any code from) is copyright 2010 Jorden Sissel.
LICENSE¶
GNU Library General Public License, Version 2.1