rabbitmq使用dead letter機制來進行retry
首先建立 工作exchange和工作queue,指定工作隊列的x-dead-letter-exchange到重試exchenge
var workQueueArgs = new Dictionary<string, object> { { "x-dead-letter-exchange", RETRY_EXCHANGE }, }; channel.ExchangeDeclare(WORK_EXCHANGE, "direct"); channel.QueueDeclare(WORK_QUEUE, true, false, false, workQueueArgs); channel.QueueBind(WORK_QUEUE, WORK_EXCHANGE, "", null);
之后建立重試exchange和重試queue
var queueArgs = new Dictionary<string, object> { { "x-dead-letter-exchange", WORK_EXCHANGE }, { "x-message-ttl", RETRY_DELAY } }; channel.ExchangeDeclare(RETRY_EXCHANGE, "direct"); channel.QueueDeclare(RETRY_QUEUE, true, false, false, queueArgs); channel.QueueBind(RETRY_QUEUE, RETRY_EXCHANGE, "", null);
重試隊列需要2個屬性,一個是 x-dead-letter-exchange,指向到工作exchange
一個是過期時間(這里等於是多少秒后重試)
監聽工作隊列,處理消息
QueueingBasicConsumer consumer = new QueueingBasicConsumer(channel); channel.BasicConsume(WORK_QUEUE, false, consumer); while (true) { BasicDeliverEventArgs e = (BasicDeliverEventArgs)consumer.Queue.Dequeue(); var message = Encoding.UTF8.GetString(e.Body); try { //throw new Exception(""); channel.BasicAck(e.DeliveryTag, false); } catch { channel.BasicNack(e.DeliveryTag, false, false); } }
處理成功調用ack,處理不成功調用nack,
調用nack后,會根據工作隊列的x-dead-letter-exchange自動把消息發到重試隊列
重試隊列等幾秒(x-message-ttl)后,就認為是自動失敗了,又會根據重試隊列的x-dead-letter-exchange發送回工作隊列
http://www.cnblogs.com/czcz1024/p/4195606.html