Question

API文档位于：http://kafka-python.readthedocs.org/en/latest/apidoc/kafka.consumer.html

但是当我运行以下代码时，异常是％d格式：需要一个数字，而不是NoneType

    client = KafkaClient("localhost:9092")
    consumer = SimpleConsumer(client, "test-group", "test")
    consumer.seek(0, whence=None)# (0,2) and (0,0)
    run = True
    while( run ):
        message = consumer.get_message(block=False, timeout=4000)

    except Exception as e:
        print "Exception while trying to read msg:", str(e)

当我使用下面的代码时，例外是 seek（）得到了一个意外的关键字参数＆＃39; partition＆＃39;

consumer.seek(0, whence=None, partition=None)# (0,2) and (0,0)

有什么想法吗？感谢。

Answer 1

在《卡夫卡权威指南》中，有一个用Java（不是Python）编写的seek()示例代码。

public class SaveOffsetsOnRebalance implements ConsumerRebalanceListener {

         public void onPartitionsRevoked (Collection <TopicPartition> partitions) {
                  commitDBTransaction();
         }

         public void onPartitionsAssigned(Collection <TopicPartiton> partitions) {
              for(TopicPartition partition : partitions)
                  consumer.seek(partition, getOffsetFromDB(partition));
         }

     }
}   // these brackets are exactly the same as the book. I didn't change anything. You might want to though.    

   consumer.subscribe (topics, new SaveOffsetOnRebalance(consumer));
   consumer.poll(0);

   for ( TopicPartition partition : consumer.assignment())
       consumer.seek(partition, getOffsetFromDB(partition));

   while (true) {
         ConsumerRecords <String, String> records = consumer.poll(100);
         for (ConsumerRecord <String, String> record : records)
         { 
               processRecord(record);
               storeRecordInDB(record);
               storeOffsetInDB(record.topic(), record.partition(), record.offset());
         }
         commitDBTransaction();
   }

如何使用kafka.consumer.SimpleConsumer，seek（）

1 个答案: