c# - 在C#中的rabbit Mq中获取xDeath中队列消息的最大重试次数

Question

我想在 rabbit MQ 中实现 DLX，它设置失败消息的重试次数。如果重试次数大于 5，则消息将被自动丢弃。

下面是 DLX 的片段。

        string WORK_EXCHANGE = "DeadExchange"; // dead letter exchange
        string RETRY_QUEUE = "RetryQueue";
        int RETRY_DELAY = 10000;

        var queueArgs = new Dictionary<string, object> {
            { "x-dead-letter-exchange", WORK_EXCHANGE },
            { "x-message-ttl", RETRY_DELAY }
        };

        var properties = channel.CreateBasicProperties();
        properties.Persistent = true;

        channel.ExchangeDeclare(exchange: WORK_EXCHANGE,
                                type: ExchangeType.Direct);

        channel.QueueBind(queue: queueName, exchange: WORK_EXCHANGE, routingKey: routingKey, arguments: null);

        channel.ExchangeDeclare(exchange: RETRY_EXCHANGE,
                                type: ExchangeType.Direct);

        channel.QueueDeclare(queue: RETRY_QUEUE, durable: true, exclusive: false, autoDelete: false, arguments: queueArgs);
        channel.QueueBind(queue: RETRY_QUEUE, exchange: RETRY_EXCHANGE, routingKey: routingKey, arguments: null);
        channel.BasicPublish(exchange: RETRY_EXCHANGE, routingKey: routingKey, mandatory: true, basicProperties: properties, body: message);

我想读取 x-Death 属性，如下面的队列消息所示。

到目前为止我已经达到了

(BasicDeliveryEventArgs)ea.BasicProperties.Headers["x-death"]

Answer 1

您可以通过这种方式检索计数:

    private long? GetRetryCount(IBasicProperties properties)
    {
        if (properties.Headers.ContainsKey("x-death"))
        {
            var deathProperties = (List<object>)properties.Headers["x-death"];
            var lastRetry = (Dictionary<string, object>)deathProperties[0];
            var count = lastRetry["count"];
            return (long)count;
        }
        else
        {
            return null;
        }
    }

希望对大家有用