README.md
[EZMQ (Effortless ZeroMQ)](https://colstrom.github.io/ezmq/)
========================
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Overview
--------
EZMQ is a wrapper around the wonderful `ffi-rzmq` gem, which (as the name suggests) uses FFI, and exposes a fairly raw C-like interface. As elegant as 0MQ is, C doesn't feel like Ruby, and FFI bindings feel like C. EZMQ makes some reasonable assumptions to help you focus on what makes your code special, and not worry about setting up 0MQ.
Any of the magical hand-wavey bits (contexts, sockets, etc) are still exposed for tinkering, EZMQ just starts you off with some sane defaults.
Examples
========
Most of these examples are trivial, because ZMQ is just the fabric of your networked application(s).
Echo Server
-----------
Waits for a request, replies with the same request.
```
require 'ezmq'
server = EZMQ::Server.new
server.listen do |message|
message
end
```
Synchronous Client Request
--------------------------
Sends a message, prints the reply when it arrives.
```
require 'ezmq'
client = EZMQ::Client.new
puts client.request 'test'
```
Confirming Logging Server
-------------------------
Waits for a request, prints it to STDOUT, and thanks the client for it.
```
require 'ezmq'
server = EZMQ::Server.new
server.listen do |message|
puts message
'Thanks for the message!' # The return of the block is sent to the client.
end
```
JSON Echo Server
----------------
Waits for JSON message, decodes it, re-encodes it, and sends it back.
```
require 'ezmq'
require 'json'
server = EZMQ::Server.new encode: -> m { JSON.dump m }, decode: -> m { JSON.load m }
server.listen do |message|
message
end
```
JSON Synchronous Client Request
-------------------------------
Encodes a message in JSON, sends it twice, prints the first one raw, and decodes the second.
```
require 'ezmq'
require 'json'
client = EZMQ::Client.new encode: -> m { JSON.dump m }
puts client.request 'test'
client.decode = -> m { JSON.load m }
puts client.request 'test'
```
'foorever' Publisher
--------------------
Publishes an endless stream of 'foo's with a topic of 'foorever'.
```
require 'ezmq'
publisher = EZMQ::Publisher.new
loop do
publisher.send 'foo', topic: 'foorever'
end
```
'foorever' Subscriber
---------------------
Subscribes to topic 'foorever', prints any messages it receives.
```
require 'ezmq'
subscriber = EZMQ::Subscriber.new topic: 'foorever'
subscriber.listen do |message, topic|
puts "[#{ topic }] #{ message }"
end
````
Pipeline Work Generator
------------------------
Generates work, distributes it to workers via PUSH socket.
```
require 'ezmq'
require 'json'
generator = EZMQ::Pusher.new :bind, encode: -> m { JSON.dump m }
15.times do |id|
work = { 'id' => "task_#{ id }", 'request' => '100' }
puts "Generated work #{work}"
generator.send work
end
```
Pipeline Workers
---------------
3 worker threads PULL work from the Generator and PUSH results to the Collector.
The 'work' here is generating a random number between 1 and a requested maximum.
```
require 'ezmq'
require 'json'
workers = []
3.times do |id|
workers << Thread.new do
input = EZMQ::Puller.new :connect, decode: -> m { JSON.load m }
output = EZMQ::Pusher.new port: 5556, encode: -> m { JSON.dump m }
input.listen do |work|
puts "Worker #{id} pulled #{work}"
result = rand(1..work['request'].to_i)
report = { 'id' => work['id'], 'result' => result }
output.send report
end
end
end
workers.each(&:join)
```
Pipeline Results Collector
--------------------------
PULLs results from workers and prints it to STDOUT.
```
require 'ezmq'
require 'json'
collector = EZMQ::Puller.new port: 5556
collector.listen do |message|
puts message
end
```
Operating System Notes
======================
As this relies on [ffi-rzmq](https://github.com/chuckremes/ffi-rzmq), you will need to have the zeromq libraries available.
For OSX, [Homebrew](http://brew.sh/) is probably the easiest way to handle this:
```brew install zeromq```
For Ubuntu, [Chris Lea's PPA](https://launchpad.net/~chris-lea/+archive/ubuntu/zeromq) is a good choice:
```
sudo add-apt-repository ppa:chris-lea/zeromq
sudo aptitude update
sudo aptitude install libzmq3-dev
```
For Windows, you should really consult the [ØMQ documentation](http://zeromq.org/docs:windows-installations).