python/streaming/queue_stream.py

0001 #
0002 # Licensed to the Apache Software Foundation (ASF) under one or more
0003 # contributor license agreements.  See the NOTICE file distributed with
0004 # this work for additional information regarding copyright ownership.
0005 # The ASF licenses this file to You under the Apache License, Version 2.0
0006 # (the "License"); you may not use this file except in compliance with
0007 # the License.  You may obtain a copy of the License at
0008 #
0009 #    http://www.apache.org/licenses/LICENSE-2.0
0010 #
0011 # Unless required by applicable law or agreed to in writing, software
0012 # distributed under the License is distributed on an "AS IS" BASIS,
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0014 # See the License for the specific language governing permissions and
0015 # limitations under the License.
0016 #
0017
0018 """
0019  Create a queue of RDDs that will be mapped/reduced one at a time in
0020  1 second intervals.
0021
0022  To run this example use
0023     `$ bin/spark-submit examples/src/main/python/streaming/queue_stream.py
0024 """
0025 import time
0026
0027 from pyspark import SparkContext
0028 from pyspark.streaming import StreamingContext
0029
0030 if __name__ == "__main__":
0031
0032     sc = SparkContext(appName="PythonStreamingQueueStream")
0033     ssc = StreamingContext(sc, 1)
0034
0035     # Create the queue through which RDDs can be pushed to
0036     # a QueueInputDStream
0037     rddQueue = []
0038     for i in range(5):
0039         rddQueue += [ssc.sparkContext.parallelize([j for j in range(1, 1001)], 10)]
0040
0041     # Create the QueueInputDStream and use it do some processing
0042     inputStream = ssc.queueStream(rddQueue)
0043     mappedStream = inputStream.map(lambda x: (x % 10, 1))
0044     reducedStream = mappedStream.reduceByKey(lambda a, b: a + b)
0045     reducedStream.pprint()
0046
0047     ssc.start()
0048     time.sleep(6)
0049     ssc.stop(stopSparkContext=True, stopGraceFully=True)