Demo and workaround for post-connection delay bug in EventMachine 1.0.0

bug.rb

#!/usr/bin/env ruby
#
# Demo and workaround for post-connection delay bug in EventMachine 1.0.0
#
# See https://github.com/eventmachine/eventmachine/issues/374 for explanation.

require 'rubygems'
require 'eventmachine' # 1.0.0
require 'amqp'         # 0.8.0 / 54f18d426

# Configure AMQP, and capture async notification of connection status in
# configuration to survive reconnects.

::AMQP.settings.merge!({
        :host => "localhost", :port => 5672, :user => "guest", :pass => "guest", :vhost => "/",
        :connection_status => proc do |status|
            @channel = ::AMQP::Channel.new(::AMQP.connection) if status == :connected
        end
})

#EventMachine.epoll  = true  # exhibits same problem as select
#EventMachine.kqueue = true  # doesn't suffer

##
## Initiate AMQP connection and wait for it to complete before proceeding.
##

@mutex   = Mutex.new
@cv      = ConditionVariable.new

Thread.new do
    ::AMQP.start do |c|
        # Fix is to uncomment the following.  Not sure if this survives
        # reconnects:
        #c.pending_connect_timeout = 0.1
        @cv.signal
    end
end

@mutex.synchronize { @cv.wait(@mutex) }

##
## Watch wireline packets to observe problem (e.g. ngrep -Td lo0 port 5672).
## The first will go out, the second will delay.
##

loop do
    @channel.queue("some_queue", :durable => true).publish("some msg")
    STDIN.readline
end