pyspark流提交提交偏移到kafka

Question

According to documentation it is possible to commit offset into kafka from (scala) spark streaming application. I would like to achieve the same functionality from pyspark.
Or at least store the kafka partition, offset into external datastore (RDBMS, etc).

However the pyspark api for kafka integration only provides RDD(offset, value)] instead of RDD[ConsumerRecord] (as in scala). Is there any way to obtain (topic, partition, offset) from the python RDD? And persist it else where?

Answer 1

We can handle offset in multiple manner . One of the way we can store the Offset value in Zookeeper path in every successful processing data and read that value when we creating the stream again . Code snippet as below .

from kazoo.client import KazooClient
zk = KazooClient(hosts='127.0.0.1:2181')
zk.start()
ZOOKEEPER_SERVERS = "127.0.0.1:2181"

def get_zookeeper_instance():
    from kazoo.client import KazooClient
    if 'KazooSingletonInstance' not in globals():
        globals()['KazooSingletonInstance'] = KazooClient(ZOOKEEPER_SERVERS)
        globals()['KazooSingletonInstance'].start()
    return globals()['KazooSingletonInstance']

def save_offsets(rdd):
    zk = get_zookeeper_instance()
    for offset in rdd.offsetRanges():
        path = f"/consumers/{var_topic_src_name}"
        print(path)
        zk.ensure_path(path)
        zk.set(path, str(offset.untilOffset).encode())

    var_offset_path = f'/consumers/{var_topic_src_name}'

    try:
        var_offset = int(zk.get(var_offset_path)[0])
    except:
        print("The spark streaming started First Time and Offset value should be Zero")
        var_offset  = 0
    var_partition = 0
    enter code here
    topicpartion = TopicAndPartition(var_topic_src_name, var_partition)
    fromoffset = {topicpartion: var_offset}
    print(fromoffset)
    kvs = KafkaUtils.createDirectStream(ssc,\
                                        [var_topic_src_name],\
                                        var_kafka_parms_src,\
                                        valueDecoder=serializer.decode_message,\
                                        fromOffsets = fromoffset)
    kvs.foreachRDD(handler)
    kvs.foreachRDD(save_offsets)

Regards

Karthikeyan Rasipalayam Durairaj