examples/src/main/python/streaming/hdfs_wordcount.py

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"""
 Counts words in new text files created in the given directory
 Usage: hdfs_wordcount.py <directory>
   <directory> is the directory that Spark Streaming will use to find and read new text files.

 To run this on your local machine on directory `localdir`, run this example
    $ bin/spark-submit examples/src/main/python/streaming/hdfs_wordcount.py localdir

 Then create a text file in `localdir` and the words in the file will get counted.
"""
import sys

from pyspark import SparkContext
from pyspark.streaming import StreamingContext

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: hdfs_wordcount.py <directory>", file=sys.stderr)
        sys.exit(-1)

    sc = SparkContext(appName="PythonStreamingHDFSWordCount")
    ssc = StreamingContext(sc, 1)

    lines = ssc.textFileStream(sys.argv[1])
    counts = lines.flatMap(lambda line: line.split(" "))\
                  .map(lambda x: (x, 1))\
                  .reduceByKey(lambda a, b: a + b)
    counts.pprint()

    ssc.start()
    ssc.awaitTermination()