Question

我的堆栈是带有gevents的uwsgi。我试图用装饰器包装我的api端点，将所有请求数据（url，方法，正文和响应）推送到kafka主题，但它不起作用。我的理论是因为我正在使用gevents，并且我试图在异步模式下运行它们，实际推送到kafka的异步线程无法与gevents一起运行。并且如果我尝试使方法同步，那么它也不起作用，它在产品工作者中死亡，即在产生调用后永远不会返回。虽然这两种方法在python shell上运行良好，并且我在线程上运行uwsgi。

按照示例代码： 1.使用kafka-python（async）

    try:
        kafka_producer = KafkaProducer(bootstrap_servers=KAFKAHOST.split(','))
    except NoBrokersAvailable:
        logger.info(u'Kafka Host not available: {}'.format(KAFKAHOST))
        kafka_producer = None


    def send_message_to_kafka(topic, key, message):
        """
        :param topic: topic name
        :param key: key to decide partition
        :param message: json serializable object to send
        :return:
        """
        if not kafka_producer:
            logger.info(u'Kafka Host not available: {}'.format(KAFKAHOST))
            return
        data = json.dumps(message)
        try:
            start = time.time()
            kafka_producer.send(topic, key=str(key), value=data)
            logger.info(u'Time take to push to Kafka: {}'.format(time.time() - start))
        except KafkaTimeoutError as e:
            logger.info(u'Message not sent: {}'.format(KAFKAHOST))
            logger.info(e)
            pass
        except Exception as e:
            logger.info(u'Message not sent: {}'.format(KAFKAHOST))
            logger.exception(e)
            pass

使用py-kafka（sync）：

try:
    client = KafkaClient(hosts=KAFKAHOST)
except Exception as e:
    logger.info(u'Kafka Host Not Found: {}'.format(KAFKAHOST))
    client = None


def send_message_to_kafka(topic, key, message):
    """
    :param topic: topic name
    :param key: key to decide partition
    :param message: json serializable object to send
    :return:
    """
    if not client:
        logger.info(u'Kafka Host is None')
        return
    data = json.dumps(message)
    try:
        start = time.time()
        topic = client.topics[topic]
        with topic.get_sync_producer() as producer:
            producer.produce(data, partition_key='{}'.format(key))
        logger.info(u'Time take to push to Kafka: {}'.format(time.time() - start))
    except Exception as e:
        logger.exception(e)
        pass

Answer 1

我对pykafka有更多经验，所以我可以回答那一节。 pykafka使用可插入的线程处理程序，并且内置了gevent支持。您需要使用use_greenlets=True实例化KafkaClient。文档here

关于你的方法的其他想法。为每条消息创建一个新的主题对象和生产者是非常昂贵的。最好创建一次并重用。

# setup once
client = KafkaClient(hosts=KAFKAHOST, use_greenlets=True)
topic = client.topics[topic]
producer = topic.get_sync_producer() 

def send_message_to_kafka(producer, key, message):
    """
    :param producer: pykafka producer
    :param key: key to decide partition
    :param message: json serializable object to send
    :return:
    """

    data = json.dumps(message)
    try:
        start = time.time()
        producer.produce(data, partition_key='{}'.format(key))
        logger.info(u'Time take to push to Kafka: {}'.format(time.time() - start))
    except Exception as e:
        logger.exception(e)
        pass # for at least once delivery you will need to catch network errors and retry.

最后，kafka从批处理和压缩中获得了所有速度。使用同步生成器可以防止客户端利用这些功能。它会工作，但速度较慢，占用空间更多。某些应用程序需要同步，但如果您遇到性能瓶颈，则可能需要将应用程序重新考虑为批处理消息。

如何让kafka-python或pykafka作为uwsgi和gevent的异步生产者工作？

1 个答案: