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Diffstat (limited to 'python/pyspark/streaming/flume.py')
| -rw-r--r-- | python/pyspark/streaming/flume.py | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/python/pyspark/streaming/flume.py b/python/pyspark/streaming/flume.py new file mode 100644 index 0000000000..cbb573f226 --- /dev/null +++ b/python/pyspark/streaming/flume.py @@ -0,0 +1,147 @@ +# +# 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. +# + +import sys +if sys.version >= "3": + from io import BytesIO +else: + from StringIO import StringIO +from py4j.java_gateway import Py4JJavaError + +from pyspark.storagelevel import StorageLevel +from pyspark.serializers import PairDeserializer, NoOpSerializer, UTF8Deserializer, read_int +from pyspark.streaming import DStream + +__all__ = ['FlumeUtils', 'utf8_decoder'] + + +def utf8_decoder(s): + """ Decode the unicode as UTF-8 """ + return s and s.decode('utf-8') + + +class FlumeUtils(object): + + @staticmethod + def createStream(ssc, hostname, port, + storageLevel=StorageLevel.MEMORY_AND_DISK_SER_2, + enableDecompression=False, + bodyDecoder=utf8_decoder): + """ + Create an input stream that pulls events from Flume. + + :param ssc: StreamingContext object + :param hostname: Hostname of the slave machine to which the flume data will be sent + :param port: Port of the slave machine to which the flume data will be sent + :param storageLevel: Storage level to use for storing the received objects + :param enableDecompression: Should netty server decompress input stream + :param bodyDecoder: A function used to decode body (default is utf8_decoder) + :return: A DStream object + """ + jlevel = ssc._sc._getJavaStorageLevel(storageLevel) + + try: + helperClass = ssc._jvm.java.lang.Thread.currentThread().getContextClassLoader()\ + .loadClass("org.apache.spark.streaming.flume.FlumeUtilsPythonHelper") + helper = helperClass.newInstance() + jstream = helper.createStream(ssc._jssc, hostname, port, jlevel, enableDecompression) + except Py4JJavaError as e: + if 'ClassNotFoundException' in str(e.java_exception): + FlumeUtils._printErrorMsg(ssc.sparkContext) + raise e + + return FlumeUtils._toPythonDStream(ssc, jstream, bodyDecoder) + + @staticmethod + def createPollingStream(ssc, addresses, + storageLevel=StorageLevel.MEMORY_AND_DISK_SER_2, + maxBatchSize=1000, + parallelism=5, + bodyDecoder=utf8_decoder): + """ + Creates an input stream that is to be used with the Spark Sink deployed on a Flume agent. + This stream will poll the sink for data and will pull events as they are available. + + :param ssc: StreamingContext object + :param addresses: List of (host, port)s on which the Spark Sink is running. + :param storageLevel: Storage level to use for storing the received objects + :param maxBatchSize: The maximum number of events to be pulled from the Spark sink + in a single RPC call + :param parallelism: Number of concurrent requests this stream should send to the sink. + Note that having a higher number of requests concurrently being pulled + will result in this stream using more threads + :param bodyDecoder: A function used to decode body (default is utf8_decoder) + :return: A DStream object + """ + jlevel = ssc._sc._getJavaStorageLevel(storageLevel) + hosts = [] + ports = [] + for (host, port) in addresses: + hosts.append(host) + ports.append(port) + + try: + helperClass = ssc._jvm.java.lang.Thread.currentThread().getContextClassLoader() \ + .loadClass("org.apache.spark.streaming.flume.FlumeUtilsPythonHelper") + helper = helperClass.newInstance() + jstream = helper.createPollingStream( + ssc._jssc, hosts, ports, jlevel, maxBatchSize, parallelism) + except Py4JJavaError as e: + if 'ClassNotFoundException' in str(e.java_exception): + FlumeUtils._printErrorMsg(ssc.sparkContext) + raise e + + return FlumeUtils._toPythonDStream(ssc, jstream, bodyDecoder) + + @staticmethod + def _toPythonDStream(ssc, jstream, bodyDecoder): + ser = PairDeserializer(NoOpSerializer(), NoOpSerializer()) + stream = DStream(jstream, ssc, ser) + + def func(event): + headersBytes = BytesIO(event[0]) if sys.version >= "3" else StringIO(event[0]) + headers = {} + strSer = UTF8Deserializer() + for i in range(0, read_int(headersBytes)): + key = strSer.loads(headersBytes) + value = strSer.loads(headersBytes) + headers[key] = value + body = bodyDecoder(event[1]) + return (headers, body) + return stream.map(func) + + @staticmethod + def _printErrorMsg(sc): + print(""" +________________________________________________________________________________________________ + + Spark Streaming's Flume libraries not found in class path. Try one of the following. + + 1. Include the Flume library and its dependencies with in the + spark-submit command as + + $ bin/spark-submit --packages org.apache.spark:spark-streaming-flume:%s ... + + 2. Download the JAR of the artifact from Maven Central http://search.maven.org/, + Group Id = org.apache.spark, Artifact Id = spark-streaming-flume-assembly, Version = %s. + Then, include the jar in the spark-submit command as + + $ bin/spark-submit --jars <spark-streaming-flume-assembly.jar> ... + +________________________________________________________________________________________________ + +""" % (sc.version, sc.version)) |