syd / em-proxy

EventMachine proxies for performance, monitoring and scale

EM-Proxy¶ ↑

EventMachine Proxy DSL for writing high-performance transparent / intercepting proxies in Ruby.

• Slides from RailsConf 2009: bit.ly/D7oWB

• GoGaRuCo notes & Slides: www.igvita.com/2009/04/20/ruby-proxies-for-scale-and-monitoring/

Getting started¶ ↑

# install & configure gemcutter repos
gem update --system
gem install gemcutter
gem tumble

gem install em-proxy

irb:0> require 'em-proxy'

Simple port forwarding proxy¶ ↑

Proxy.start(:host => "0.0.0.0", :port => 80, :debug => true) do |conn|
  conn.server :srv, :host => "127.0.0.1", :port => 81

  # modify / process request stream
  conn.on_data do |data|
    p [:on_data, data]
    data
  end

  # modify / process response stream
  conn.on_response do |backend, resp|
    p [:on_response, backend, resp]
    resp
  end

  # termination logic
  conn.on_finish do |backend, name|
    p [:on_finish, name]

    # terminate connection (in duplex mode, you can terminate when prod is done)
    unbind if backend == :srv
  end
end

For more examples see the /examples directory.

• SMTP Spam Filtering

• Duplicating traffic

• Selective forwarding

• Beanstalkd interceptor

• etc.