em-zeromq

Description:

EventMachine support for ZeroMQ

Usage:

Tested and functional with Rubinius, jRuby, and 1.9.2.

If using 1.9.2 you must gem install ffi before using.

MRI 1.8.7 does not work with libzmq.

Want to help out? Ask!

Warning !!

To ensure your zeromq context won't be reclaimed by the ruby garbage collector you need to keep a reference to it in scope, this is what you don't want to do:

EM.run do
  context = EM::ZeroMQ::Context.new(1)
  dealer_socket = context.connect(...)
  dealer_socket.send_msg('', "ping")
end

If you do this everything will appear to work fine at first but as soon as the garbage collector is triggered your context will get destroyed and your application will hang.

The same should be true for references to socket.
It should not be a major problem anyway since code like above is only written for examples but I just pulled my hair trying to figure out why my test code was not working so now you have been warned !

Example

require 'rubygems'
require 'em-zeromq'
    
Thread.abort_on_exception = true

class EMTestPullHandler
  attr_reader :received
  def on_readable(socket, messages)
    messages.each do |m|
      puts m.copy_out_string
    end
  end
end


ctx = EM::ZeroMQ::Context.new(1)
EM.run do
  # setup push sockets
  push_socket1 = ctx.bind( ZMQ::PUSH, 'tcp://127.0.0.1:2091')
  push_socket2 = ctx.bind( ZMQ::PUSH, 'ipc:///tmp/a')
  push_socket3 = ctx.bind( ZMQ::PUSH, 'inproc://simple_test')
  
  # setup one pull sockets listening to both push sockets
  pull_socket = ctx.connect( ZMQ::PULL, 'tcp://127.0.0.1:2091', EMTestPullHandler.new)
  pull_socket.connect('ipc:///tmp/a')
  pull_socket.connect('inproc://simple_test')
  
  n = 0
  
  # push_socket.hwm = 40
  # puts push_socket.hwm
  # puts pull_socket.hwm
  
  EM::PeriodicTimer.new(0.1) do
    puts '.'
    push_socket1.send_msg("t#{n += 1}_")
    push_socket2.send_msg("i#{n += 1}_")
    push_socket3.send_msg("p#{n += 1}_")
  end
end

License:

(The MIT License)

Copyright (c) 2011

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.