Question

我正在尝试使用Pika 0.11.2从RabbitMQ服务器获取消息时验证channel.consume

当调用get_mq并且我检测到：队列中的空消息时发生异常。那么，我该如何验证异常

这是我的代码：

def send_mq(self, message, queue_name):
    try:
        if message and queue_name:
            message = json.dumps(message)
            self.connect(queue_name)
            self.channel.basic_publish(exchange="", routing_key=queue_name, body=message)
            if self.mqConn:
                self.mqConn.close()
    except Exception as ex:
        sentry_log('send_mq_error', str(ex))

def get_mq(self, callback, queue_name, limit_message=0):
    if callback and queue_name:
        self.connect(queue_name)
        queue = self.channel.queue_declare(queue=queue_name, durable=True, exclusive=False, auto_delete=False)
        # Enabled delivery confirmations
        self.channel.confirm_delivery()
        if queue and queue.method.message_count > 0:
            # method_frame, header_frame, body = self.channel.basic_get(queue=queue_name)
            # self.channel.basic_ack(delivery_tag=method_frame.delivery_tag)
            # self.channel.basic_qos(prefetch_count=1)
            # self.channel.basic_consume(lambda ch, method, properties, body: callback(json.loads(body) if body else body), queue=queue_name, no_ack=True)
            # # # start consuming (blocks)
            # try:
            #     self.channel.start_consuming()
            # except KeyboardInterrupt:
            #     self.channel.stop_consuming()
            try:
                # Get ten messages and break out
                for method_frame, properties, body in self.channel.consume(queue=queue_name, inactivity_timeout=1):
                    if body:
                        # Acknowledge the message
                        self.channel.basic_ack(method_frame.delivery_tag)
                        self.channel.basic_qos(prefetch_count=1)

                        # Escape out of the loop with limit messages
                        if limit_message > 0 and method_frame.delivery_tag == limit_message:
                            break

                        callback(json.loads(body))
                    else:
                        break
                self.channel.cancel()
            except Exception as ex:
                self.channel.cancel()
                if self.mqConn:
                    self.mqConn.close()

错误消息：

'Nonetype'对象不可迭代

Answer 1

RabbitMQ团队监控the rabbitmq-users mailing list，有时只回答StackOverflow上的问题。

你好，我是Pika的维护者之一。 consume方法可以返回3元组或 None，因此您应该使用provided in this comment方法处理它。

此拉取请求已解决此问题，并将在下一版本的Pika中发布：https://github.com/pika/pika/pull/901

Pika - 如何在开始使用时处理NoneTypes异常

1 个答案: