A helper that starts EventMachine reactor the optimal way depending on what Web server (if any) you are running. It should not be considered a 100% safe, general purpose EventMachine reactor "on/off switch" but is very useful in Web applications and some stand-alone applications.
This helper was inspired by Qusion project by Dan DeLeo.
h2. Key methods
# File lib/amqp/utilities/event_loop_helper.rb, line 22 def self.eventmachine_thread @eventmachine_thread end
# File lib/amqp/utilities/event_loop_helper.rb, line 26 def self.reactor_running? EventMachine.reactor_running? end
A helper that detects what app server (if any) is running and starts EventMachine reactor in the most optimal way. For event-driven servers like Thin and Goliath, this means relying on them starting the reactor but delaying execution of a block you pass to {EventLoopHelper.run} until reactor is actually running.
For Unicorn, Passenger, Mongrel and other servers and standalone apps EventMachine is started in a separate thread.
@example Using EventLoopHelper.run to start EventMachine reactor the optimal way without blocking current thread
AMQP::Utilities::EventLoopHelper.run do # Sets up default connection, accessible via AMQP.connection, and opens a channel # accessible via AMQP.channel for convenience AMQP.start exchange = AMQP.channel.fanout("amq.fanout") AMQP.channel.queue("", :auto_delete => true, :exclusive => true).bind(exchange) AMQP::channel.default_exchange.publish("Started!", :routing_key => AMQP::State.queue.name) end
@return [Thread] A thread EventMachine event loop will be started in (there is no guarantee it is already running).
@note This method, unlike EventMachine.run, DOES NOT block current thread.
# File lib/amqp/utilities/event_loop_helper.rb, line 62 def self.run(&block) if reactor_running? EventMachine.run(&block) return end @eventmachine_thread ||= begin case self.server_type when :thin, :goliath, :evented_mongrel then EventMachine.next_tick { block.call } Thread.current when :unicorn, :passenger, :mongrel, :scgi, :webrick, nil then t = Thread.new { EventMachine.run(&block) } # give EventMachine reactor some time to start sleep(0.25) t else t = Thread.new { EventMachine.run(&block) } # give EventMachine reactor some time to start sleep(0.25) t end end @eventmachine_thread end
Type of server (if any) that is running.
@see AMQP::Utilities::ServerType.detect
# File lib/amqp/utilities/event_loop_helper.rb, line 33 def self.server_type @server_type ||= ServerType.detect end
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