added sparkContext as input parameter in StreamingContext

Author: giwa

python/pyspark/streaming/context.py

@@ -34,7 +34,7 @@ class StreamingContext(object):
 
     def __init__(self, master=None, appName=None, sparkHome=None, pyFiles=None,
         environment=None, batchSize=1024, serializer=PickleSerializer(), conf=None,
-        gateway=None, duration=None):
+        gateway=None, sparkContext=None, duration=None):
         """
         Create a new StreamingContext. At least the master and app name and duration
         should be set, either through the named parameters here or through C{conf}.
@@ -55,14 +55,18 @@ def __init__(self, master=None, appName=None, sparkHome=None, pyFiles=None,
         @param conf: A L{SparkConf} object setting Spark properties.
         @param gateway: Use an existing gateway and JVM, otherwise a new JVM
                will be instatiated.
-        @param duration: A L{Duration} Duration for SparkStreaming
+        @param sparkContext: L{SparkContext} object.
+        @param duration: A L{Duration} object for SparkStreaming.
 
         """
 
-        # Create the Python Sparkcontext
-        self._sc = SparkContext(master=master, appName=appName, sparkHome=sparkHome,
-                        pyFiles=pyFiles, environment=environment, batchSize=batchSize,
-                        serializer=serializer, conf=conf, gateway=gateway)
+        if sparkContext is None:
+            # Create the Python Sparkcontext
+            self._sc = SparkContext(master=master, appName=appName, sparkHome=sparkHome,
+                            pyFiles=pyFiles, environment=environment, batchSize=batchSize,
+                            serializer=serializer, conf=conf, gateway=gateway)
+        else:
+            self._sc = sparkContext
 
         # Start py4j callback server.
         # Callback sever is need only by SparkStreming; therefore the callback sever