AssertionError: Unassigned partition

Question

我试图通过设置偏移量来使用主题中的数据，但出现断言错误 -

from kafka import KafkaConsumer

consumer = KafkaConsumer('foobar1',
                         bootstrap_servers=['localhost:9092'])
print 'process started'
print consumer.partitions_for_topic('foobar1')
print 'done'
consumer.seek(0,10)

for message in consumer:
    print ("%s:%d:%d: key=%s value=%s" % (message.topic, message.partition,
                                          message.offset, message.key,
                                          message.value))
print 'process ended'

错误：-

Traceback (most recent call last):
  File "/Users/pn/Documents/jobs/ccdn/kafka_consumer_1.py", line 21, in <module>
    consumer.seek(0,10)
  File "/Users/pn/.virtualenvs/vpsq/lib/python2.7/site-packages/kafka/consumer/group.py", line 549, in seek
    assert partition in self._subscription.assigned_partitions(), 'Unassigned partition'
AssertionError: Unassigned partition

Answer 1

在调用 seek 之前，您必须使用 TopicPartition 列表调用 consumer.assign()。另请注意，seek 的第一个参数也是一个 TopicPartition。参见 KafkaConsumer API

Answer 2

在我使用 Kafka 0.9 和 kafka-python 的情况下，分区分配发生在 for message in consumer 期间。因此，搜索操作应该在迭代之后。我通过以下代码重置了我的组的偏移量：

import kafka

ps = []
for i in xrange(topic_partition_number):
    ps.append(kafka.TopicPartition(topic, i))

consumer = kafka.KafkaConsumer(topic, bootstrap_servers=address, group_id=group)
for msg in consumer:
    print msg
    consumer.seek_to_beginning(*ps)
    consumer.commit()
    break

Answer 3

下面是解决问题的例子：

from kafka import KafkaConsumer, TopicPartition

con = KafkaConsumer(bootstrap_servers = my_bootstrapservers)
tp = TopicPartition(my_topic, 0)
con.assign([tp])
con.seek_to_beginning()
con.seek(tp, 1000000)

参考：

AssertionError: Unassigned partition

AssertionError: Unassigned partition

apache-kafka

kafka-consumer-api

kafka-python