For SmartChat we used SQS. We used this as a way of sending messages for background workers instead of Sidekiq or Resque. This worked well, but for local development having to use AWS resources wasn’t ideal. We set about creating a way of using Redis instead.
The SQS interface that we used was very simple. It has two methods that were used, #send_messsage and #poll. With this we can make a redis version.
redis_queue.rb
require 'redis'
RedisMessage = Struct.new(:body)
class RedisQueue
def initialize(redis)
@redis = redis
end
def poll(&block)
loop do
queue, message = @redis.brpop("smartchat-queue")
# queue could be nil if a timeout happened
if queue
block.call(RedisMessage.new(message))
end
end
end
def send_message(message_json)
@redis.lpush("smartchat-queue", message_json)
end
end
To use this, we have a AppContainer switch to it for development purposes and use it normally.
config/initializers/app_container.rb
#...
let(:queue) do
if Rails.env.development? || Rails.env.all?
require 'redis_queue'
RedisQueue.new(redis)
else
AWS::SQS.new.queues.named(sqs_queue_name)
end
end
#...
libexec/smartchat-daemon.rb
AppContainer.queue.poll do |msg|
body = JSON.parse(msg.body)
# do work
end
