clean up code

python/pyspark/streaming/context.py

@@ -72,21 +72,19 @@ def __init__(self, master=None, appName=None, sparkHome=None, pyFiles=None,
         # Callback sever is need only by SparkStreming; therefore the callback sever
         # is started in StreamingContext.
         SparkContext._gateway.restart_callback_server()
-        self._clean_up_trigger()
+        self._set_clean_up_trigger()
         self._jvm = self._sc._jvm
         self._jssc = self._initialize_context(self._sc._jsc, duration._jduration)
 
     # Initialize StremaingContext in function to allow subclass specific initialization
     def _initialize_context(self, jspark_context, jduration):
         return self._jvm.JavaStreamingContext(jspark_context, jduration)
 
-    def _clean_up_trigger(self):
+    def _set_clean_up_trigger(self):
         """Kill py4j callback server properly using signal lib"""
 
         def clean_up_handler(*args):
             # Make sure stop callback server.
-            # This need improvement how to terminate callback sever properly.
-            SparkContext._gateway._shutdown_callback_server()
             SparkContext._gateway.shutdown()
             sys.exit(0)
 
@@ -132,18 +130,15 @@ def stop(self, stopSparkContext=True, stopGraceFully=False):
         Stop the execution of the streams immediately (does not wait for all received data
         to be processed).
         """
-
         try:
             self._jssc.stop(stopSparkContext, stopGraceFully)
         finally:
-            # Stop Callback server
-            SparkContext._gateway._shutdown_callback_server()
             SparkContext._gateway.shutdown()
 
     def _testInputStream(self, test_inputs, numSlices=None):
         """
         This function is only for unittest.
-        It requires a sequence as input, and returns the i_th element at the i_th batch
+        It requires a list as input, and returns the i_th element at the i_th batch
         under manual clock.
         """
         test_rdds = list()

python/pyspark/streaming/dstream.py

@@ -207,7 +207,7 @@ def _defaultReducePartitions(self):
         """
         Returns the default number of partitions to use during reduce tasks (e.g., groupBy).
         If spark.default.parallelism is set, then we'll use the value from SparkContext
-        defaultParallelism, otherwise we'll use the number of partitions in this RDD.
+        defaultParallelism, otherwise we'll use the number of partitions in this RDD
 
         This mirrors the behavior of the Scala Partitioner#defaultPartitioner, intended to reduce
         the likelihood of OOMs. Once PySpark adopts Partitioner-based APIs, this behavior will
@@ -222,7 +222,8 @@ def getNumPartitions(self):
         """
         Return the number of partitions in RDD
         """
-        # TODO: remove hardcoding. RDD has NumPartitions but DStream does not have.
+        # TODO: remove hardcoding. RDD has NumPartitions. How do we get the number of partition
+        # through DStream?
         return 2
 
     def foreachRDD(self, func):
@@ -243,6 +244,10 @@ def pyprint(self):
         operator, so this DStream will be registered as an output stream and there materialized.
         """
         def takeAndPrint(rdd, time):
+            """
+            Closure to take element from RDD and print first 10 elements.
+            This closure is called by py4j callback server.
+            """
             taken = rdd.take(11)
             print "-------------------------------------------"
             print "Time: %s" % (str(time))
@@ -307,17 +312,11 @@ def checkpoint(self, interval):
         Mark this DStream for checkpointing. It will be saved to a file inside the
         checkpoint directory set with L{SparkContext.setCheckpointDir()}
 
-        I am not sure this part in DStream
-        and
-        all references to its parent RDDs will be removed. This function must
-        be called before any job has been executed on this RDD. It is strongly
-        recommended that this RDD is persisted in memory, otherwise saving it
-        on a file will require recomputation.
-
-        interval must be pysprak.streaming.duration
+        @param interval: Time interval after which generated RDD will be checkpointed
+               interval has to be pyspark.streaming.duration.Duration
         """
         self.is_checkpointed = True
-        self._jdstream.checkpoint(interval)
+        self._jdstream.checkpoint(interval._jduration)
         return self
 
     def groupByKey(self, numPartitions=None):
@@ -369,6 +368,10 @@ def saveAsTextFiles(self, prefix, suffix=None):
         Save this DStream as a text file, using string representations of elements.
         """
         def saveAsTextFile(rdd, time):
+            """
+            Closure to save element in RDD in DStream as Pickled data in file.
+            This closure is called by py4j callback server.
+            """
             path = rddToFileName(prefix, suffix, time)
             rdd.saveAsTextFile(path)
 
@@ -410,9 +413,10 @@ def get_output(rdd, time):
 # TODO: implement countByWindow
 # TODO: implement reduceByWindow
 
-# Following operation has dependency to transform
+# transform Operation
 # TODO: implement transform
 # TODO: implement transformWith
+# Following operation has dependency with transform
 # TODO: implement union
 # TODO: implement repertitions
 # TODO: implement cogroup