如何在bunny中暂停和恢复消费者

Question

有没有什么办法可以让消费者临时暂停，稍后再恢复？

下面是我想要做的一个例子：

require "bunny"
conn = Bunny.new
conn.start

ch1 = conn.create_channel
publisher = ch.direct('test', :auto_delete => false)

consumer1 = nil
Thread.new do
    ch2 = conn.create_channel(nil, 8) #Using eight worker
    queue1 = ch2.queue('', :exclusive => true)
    queue1.bind(publisher, :routing_key => 'low_priority')
    consumer1 = queue1.subscribe(:block => true) do |delivery_info, properties, payload|
       #do some work
    end
end

Thread.new do
    ch3 = conn.create_channel
    queue2 = ch3.queue('', :exclusive => true)
    queue2.bind(publisher, :routing_key => 'high_priority')
    consumer2 = queue2.subscribe(:block => true) do |delivery_info, properties, payload|
        consumer1.pause   #pause the other consumer
        #do other things
        consumer1.resume  #resume the consumer
    end
end
#rest of the code

当我在consumer2工作时，我想暂停consumer1。有什么有效的方法可以做到这一点吗？

Answer 1

如果你想创建优先级策略，bunny已经实现了：

http://rubybunny.info/articles/queues.html#consumer_priorities

q = ch.queue("a.queue")
q.subscribe(:manual_ack => true, :arguments => {"x-priority" => 5}) do |delivery_info, properties, payload|
  # ...
end
q.subscribe(:manual_ack => true, :arguments => {"x-priority" => 2}) do |delivery_info, properties, payload|
  # ...
end

如果你想并行处理它，我推荐这个gem：

https://github.com/grosser/parallel

示例：

results = Parallel.map(['a','b','c'], in_processes: 3) { |one_letter| ... }

希望能有所帮助。