Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/3715#discussion_r23661437
--- Diff: python/pyspark/streaming/kafka.py ---
@@ -0,0 +1,82 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from py4j.java_collections import MapConverter
+from py4j.java_gateway import java_import, Py4JError
+
+from pyspark.storagelevel import StorageLevel
+from pyspark.serializers import PairDeserializer, NoOpSerializer
+from pyspark.streaming import DStream
+
+__all__ = ['KafkaUtils', 'utf8_decoder']
+
+
+def utf8_decoder(s):
+ """ Decode the unicode as UTF-8 """
+ return s and s.decode('utf-8')
+
+
+class KafkaUtils(object):
+
+ @staticmethod
+ def createStream(ssc, zkQuorum, groupId, topics,
+ storageLevel=StorageLevel.MEMORY_AND_DISK_SER_2,
+ keyDecoder=utf8_decoder, valueDecoder=utf8_decoder):
+ """
+ Create an input stream that pulls messages from a Kafka Broker.
+
+ :param ssc: StreamingContext object
+ :param zkQuorum: Zookeeper quorum
(hostname:port,hostname:port,..).
+ :param groupId: The group id for this consumer.
+ :param topics: Dict of (topic_name -> numPartitions) to consume.
+ Each partition is consumed in its own thread.
+ :param storageLevel: RDD storage level.
+ :param keyDecoder: A function used to decode key
+ :param valueDecoder: A function used to decode value
+ :return: A DStream object
+ """
+ java_import(ssc._jvm,
"org.apache.spark.streaming.kafka.KafkaUtils")
+
+ param = {
+ "zookeeper.connect": zkQuorum,
+ "group.id": groupId,
+ "zookeeper.connection.timeout.ms": "10000",
+ }
+ if not isinstance(topics, dict):
+ raise TypeError("topics should be dict")
+ jtopics = MapConverter().convert(topics,
ssc.sparkContext._gateway._gateway_client)
+ jparam = MapConverter().convert(param,
ssc.sparkContext._gateway._gateway_client)
+ jlevel = ssc._sc._getJavaStorageLevel(storageLevel)
+
+ def getClassByName(name):
+ return ssc._jvm.org.apache.spark.util.Utils.classForName(name)
+
+ try:
+ array = getClassByName("[B")
+ decoder = getClassByName("kafka.serializer.DefaultDecoder")
+ jstream = ssc._jvm.KafkaUtils.createStream(ssc._jssc, array,
array, decoder, decoder,
+ jparam, jtopics,
jlevel)
+ except Py4JError, e:
+ # TODO: use --jar once it also work on driver
+ if not e.message or 'call a package' in e.message:
--- End diff --
This is clever; the 'call a package' errors are _really_ confusing to
users, so this message is pretty helpful.
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