Class: BirdGrinder::QueueProcessor

Inherits:
Object
  • Object
show all
Defined in:
lib/bird_grinder/queue_processor.rb

Overview

When running, the queue processor makes it possible to use a redis queue queue up and dispatch tweets and direct messages from external processes. This is useful since it makes it easy to have 1 outgoing source of tweets, triggered from any external application. Included in examples/bird_grinder_client.rb is a simple example client which uses redis to queue tweets and dms.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ QueueProcessor

Initializes redis and our tweeter.



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# File 'lib/bird_grinder/queue_processor.rb', line 24

def initialize
  @tweeter = Tweeter.new(self)
  @redis   = EM::P::Redis.connect
end

Instance Attribute Details

#tweeter ⇒ Object

Returns the value of attribute tweeter.



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# File 'lib/bird_grinder/queue_processor.rb', line 21

def tweeter
  @tweeter
end

Class Method Details

.start ⇒ Object

Starts the queue processor with an initial check. raises an exception if the reactor isn’t running.



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# File 'lib/bird_grinder/queue_processor.rb', line 80

def self.start
  raise "EventMachine must be running" unless EM.reactor_running?
  new.check_queue
end

Instance Method Details

#check_queue ⇒ Object

Attempts to pop and process an item from the front of the queue. Also, it will queue up the next check - if current item was empty, it will happen after a specified delay otherwise it will check now.



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# File 'lib/bird_grinder/queue_processor.rb', line 32

def check_queue
  logger.debug "Checking Redis for outgoing messages"
  @redis.lpop(@@namespace) do |res|
    if res.blank?
      logger.debug "Empty queue, scheduling check in #{@@polling_delay} seconds"
      schedule_check(@@polling_delay)
    else
      logger.debug "Got item, processing and scheduling next check"
      begin
        process_action Yajl::Parser.parse(res)
      rescue Yajl::ParseError => e
        logger.error "Couldn't parse json: #{e.message}"
      end
      schedule_check
    end
  end
end

#handle_action(action, args) ⇒ Object

Calls the correct method on the tweeter if present and in the whitelist. logs and caught argument errors.



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# File 'lib/bird_grinder/queue_processor.rb', line 71

def handle_action(action, args)
  args ||= []
  @tweeter.send(action, *[*args]) if @@action_whitelist.include?(action)
rescue ArgumentError
  logger.warn "Incorrect call for #{action} with arguuments #{args}"
end

#process_action(res) ⇒ Object

Processes a given action action - calling handle action if present.



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# File 'lib/bird_grinder/queue_processor.rb', line 63

def process_action(res)
  if res.is_a?(Hash) && res["action"].present?
    handle_action(res["action"], res["arguments"])
  end
end

#schedule_check(time = nil) ⇒ Object

Check the queue.

Parameters:

  • time (Integer, nil) (defaults to: nil) —

    the specified delay. If nil, it will be done now.



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# File 'lib/bird_grinder/queue_processor.rb', line 53

def schedule_check(time = nil)
  if time == nil
    check_queue
  else
    EventMachine.add_timer(@@polling_delay) { check_queue }
  end
end