Question

我发现这是用kafka-consumer-groups.sh工具How to change start offset for topic?重置LAG的地方，但我需要在应用程序中重置它。我找到了这个例子，但它似乎没有重置它。 kafka-python read from last produced message after a consumer restart示例

    consumer = KafkaConsumer("MyTopic", bootstrap_servers=self.kafka_server + ":" + str(self.kafka_port),
                             enable_auto_commit=False,
                             group_id="MyTopic.group")
    consumer.poll()
    consumer.seek_to_end()
    consumer.commit()

    ... continue on with other code...

运行bin\windows\kafka-consumer-groups.bat --bootstrap-server localhost:9092 --group MyTopic.group --describe仍然显示两个分区都有LAG。如何才能将当前偏移量转移到“快速前进”＃34;到最后？

TOPIC           PARTITION  CURRENT-OFFSET  LOG-END-OFFSET  LAG             CONSUMER-ID                                             HOST             CLIENT-ID
MyTopic         0          52110           66195           14085           kafka-python-1.4.2-6afb6901-c651-4534-a482-15358db42c22 /Host1  kafka-python-1.4.2
MyTopic         1          52297           66565           14268           kafka-python-1.4.2-c70e0a71-7d61-46a1-97bc-aa2726a8109b /Host2  kafka-python-1.4.2

Answer 1

您可能想要这个：

def consumer_from_offset(topic, group_id, offset):
    """return the consumer from a certain offset"""
    consumer = KafkaConsumer(bootstrap_servers=broker_list, group_id=group_id)
    tp = TopicPartition(topic=topic, partition=0)
    consumer.assign([tp])
    consumer.seek(tp, offset)

    return consumer

consumer = consumer_from_offset('topic', 'group', 0)
for msg in consumer:
    # it will consume the msg beginning from offset 0
    print(msg)

Answer 2

为了“快进”消费者组的偏移量，意味着清除LAG，您需要创建将加入同一组的新消费者。
控制台命令是：

kafka-console-consumer.sh --bootstrap-server <brokerIP>:9092 --topic <topicName> --consumer-property group.id=<groupName>

与此同时，你可以运行命令来查看你描述的滞后，你会看到延迟消失。

在Kafka-python中重置消费者组内的kafka LAG（更改偏移量）

2 个答案: