diff options
Diffstat (limited to 'python/pyspark/streaming/kafka.py')
| -rw-r--r-- | python/pyspark/streaming/kafka.py | 167 |
1 files changed, 160 insertions, 7 deletions
diff --git a/python/pyspark/streaming/kafka.py b/python/pyspark/streaming/kafka.py index 8d610d6569..e278b29003 100644 --- a/python/pyspark/streaming/kafka.py +++ b/python/pyspark/streaming/kafka.py @@ -17,11 +17,12 @@ from py4j.java_gateway import Py4JJavaError +from pyspark.rdd import RDD from pyspark.storagelevel import StorageLevel from pyspark.serializers import PairDeserializer, NoOpSerializer from pyspark.streaming import DStream -__all__ = ['KafkaUtils', 'utf8_decoder'] +__all__ = ['Broker', 'KafkaUtils', 'OffsetRange', 'TopicAndPartition', 'utf8_decoder'] def utf8_decoder(s): @@ -67,7 +68,104 @@ class KafkaUtils(object): except Py4JJavaError as e: # TODO: use --jar once it also work on driver if 'ClassNotFoundException' in str(e.java_exception): - print(""" + KafkaUtils._printErrorMsg(ssc.sparkContext) + raise e + ser = PairDeserializer(NoOpSerializer(), NoOpSerializer()) + stream = DStream(jstream, ssc, ser) + return stream.map(lambda k_v: (keyDecoder(k_v[0]), valueDecoder(k_v[1]))) + + @staticmethod + def createDirectStream(ssc, topics, kafkaParams, fromOffsets={}, + keyDecoder=utf8_decoder, valueDecoder=utf8_decoder): + """ + .. note:: Experimental + + Create an input stream that directly pulls messages from a Kafka Broker and specific offset. + + This is not a receiver based Kafka input stream, it directly pulls the message from Kafka + in each batch duration and processed without storing. + + This does not use Zookeeper to store offsets. The consumed offsets are tracked + by the stream itself. For interoperability with Kafka monitoring tools that depend on + Zookeeper, you have to update Kafka/Zookeeper yourself from the streaming application. + You can access the offsets used in each batch from the generated RDDs (see + + To recover from driver failures, you have to enable checkpointing in the StreamingContext. + The information on consumed offset can be recovered from the checkpoint. + See the programming guide for details (constraints, etc.). + + :param ssc: StreamingContext object. + :param topics: list of topic_name to consume. + :param kafkaParams: Additional params for Kafka. + :param fromOffsets: Per-topic/partition Kafka offsets defining the (inclusive) starting + point of the stream. + :param keyDecoder: A function used to decode key (default is utf8_decoder). + :param valueDecoder: A function used to decode value (default is utf8_decoder). + :return: A DStream object + """ + if not isinstance(topics, list): + raise TypeError("topics should be list") + if not isinstance(kafkaParams, dict): + raise TypeError("kafkaParams should be dict") + + try: + helperClass = ssc._jvm.java.lang.Thread.currentThread().getContextClassLoader() \ + .loadClass("org.apache.spark.streaming.kafka.KafkaUtilsPythonHelper") + helper = helperClass.newInstance() + + jfromOffsets = dict([(k._jTopicAndPartition(helper), + v) for (k, v) in fromOffsets.items()]) + jstream = helper.createDirectStream(ssc._jssc, kafkaParams, set(topics), jfromOffsets) + except Py4JJavaError as e: + if 'ClassNotFoundException' in str(e.java_exception): + KafkaUtils._printErrorMsg(ssc.sparkContext) + raise e + + ser = PairDeserializer(NoOpSerializer(), NoOpSerializer()) + stream = DStream(jstream, ssc, ser) + return stream.map(lambda k_v: (keyDecoder(k_v[0]), valueDecoder(k_v[1]))) + + @staticmethod + def createRDD(sc, kafkaParams, offsetRanges, leaders={}, + keyDecoder=utf8_decoder, valueDecoder=utf8_decoder): + """ + .. note:: Experimental + + Create a RDD from Kafka using offset ranges for each topic and partition. + :param sc: SparkContext object + :param kafkaParams: Additional params for Kafka + :param offsetRanges: list of offsetRange to specify topic:partition:[start, end) to consume + :param leaders: Kafka brokers for each TopicAndPartition in offsetRanges. May be an empty + map, in which case leaders will be looked up on the driver. + :param keyDecoder: A function used to decode key (default is utf8_decoder) + :param valueDecoder: A function used to decode value (default is utf8_decoder) + :return: A RDD object + """ + if not isinstance(kafkaParams, dict): + raise TypeError("kafkaParams should be dict") + if not isinstance(offsetRanges, list): + raise TypeError("offsetRanges should be list") + + try: + helperClass = sc._jvm.java.lang.Thread.currentThread().getContextClassLoader() \ + .loadClass("org.apache.spark.streaming.kafka.KafkaUtilsPythonHelper") + helper = helperClass.newInstance() + joffsetRanges = [o._jOffsetRange(helper) for o in offsetRanges] + jleaders = dict([(k._jTopicAndPartition(helper), + v._jBroker(helper)) for (k, v) in leaders.items()]) + jrdd = helper.createRDD(sc._jsc, kafkaParams, joffsetRanges, jleaders) + except Py4JJavaError as e: + if 'ClassNotFoundException' in str(e.java_exception): + KafkaUtils._printErrorMsg(sc) + raise e + + ser = PairDeserializer(NoOpSerializer(), NoOpSerializer()) + rdd = RDD(jrdd, sc, ser) + return rdd.map(lambda k_v: (keyDecoder(k_v[0]), valueDecoder(k_v[1]))) + + @staticmethod + def _printErrorMsg(sc): + print(""" ________________________________________________________________________________________________ Spark Streaming's Kafka libraries not found in class path. Try one of the following. @@ -85,8 +183,63 @@ ________________________________________________________________________________ ________________________________________________________________________________________________ -""" % (ssc.sparkContext.version, ssc.sparkContext.version)) - raise e - ser = PairDeserializer(NoOpSerializer(), NoOpSerializer()) - stream = DStream(jstream, ssc, ser) - return stream.map(lambda k_v: (keyDecoder(k_v[0]), valueDecoder(k_v[1]))) +""" % (sc.version, sc.version)) + + +class OffsetRange(object): + """ + Represents a range of offsets from a single Kafka TopicAndPartition. + """ + + def __init__(self, topic, partition, fromOffset, untilOffset): + """ + Create a OffsetRange to represent range of offsets + :param topic: Kafka topic name. + :param partition: Kafka partition id. + :param fromOffset: Inclusive starting offset. + :param untilOffset: Exclusive ending offset. + """ + self._topic = topic + self._partition = partition + self._fromOffset = fromOffset + self._untilOffset = untilOffset + + def _jOffsetRange(self, helper): + return helper.createOffsetRange(self._topic, self._partition, self._fromOffset, + self._untilOffset) + + +class TopicAndPartition(object): + """ + Represents a specific top and partition for Kafka. + """ + + def __init__(self, topic, partition): + """ + Create a Python TopicAndPartition to map to the Java related object + :param topic: Kafka topic name. + :param partition: Kafka partition id. + """ + self._topic = topic + self._partition = partition + + def _jTopicAndPartition(self, helper): + return helper.createTopicAndPartition(self._topic, self._partition) + + +class Broker(object): + """ + Represent the host and port info for a Kafka broker. + """ + + def __init__(self, host, port): + """ + Create a Python Broker to map to the Java related object. + :param host: Broker's hostname. + :param port: Broker's port. + """ + self._host = host + self._port = port + + def _jBroker(self, helper): + return helper.createBroker(self._host, self._port) |