Reset kafka LAG (change offset) within consumer group in Kafka-python

Question

I found this where I reset my LAG with the kafka-consumer-groups.sh tool How to change start offset for topic? but I am needing to reset it within the application. I found this example, but it doesn't seem to reset it. kafka-python read from last produced message after a consumer restart example

    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...

Running bin\windows\kafka-consumer-groups.bat --bootstrap-server localhost:9092 --group MyTopic.group --describe still shows that both partitions have a LAG. How can I get the current-offset to "fast-foward" to the end?

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

DennisLi DennisLi · Accepted Answer · 2020-01-13T10:06:12

You may want this:

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)

Reset kafka LAG (change offset) within consumer group in Kafka-python

2 Answers