[SPARK-3458] enable python "with" statements for SparkContext

allow for best practice code,

```
try:
  sc = SparkContext()
  app(sc)
finally:
  sc.stop()
```

to be written using a "with" statement,

```
with SparkContext() as sc:
  app(sc)
```

Author: Matthew Farrellee <matt@redhat.com>

Closes #2335 from mattf/SPARK-3458 and squashes the following commits:

5b4e37c [Matthew Farrellee] [SPARK-3458] enable python "with" statements for SparkContext

1 files changed, 14 insertions, 0 deletions

diff --git a/python/pyspark/context.py b/python/pyspark/context.py
index 5a30431568..84bc0a3b7c 100644
--- a/python/pyspark/context.py
+++ b/python/pyspark/context.py
@@ -232,6 +232,20 @@ class SparkContext(object):
                 else:
                     SparkContext._active_spark_context = instance
 
+    def __enter__(self):
+        """
+        Enable 'with SparkContext(...) as sc: app(sc)' syntax.
+        """
+        return self
+
+    def __exit__(self, type, value, trace):
+        """
+        Enable 'with SparkContext(...) as sc: app' syntax.
+
+        Specifically stop the context on exit of the with block.
+        """
+        self.stop()
+
     @classmethod
     def setSystemProperty(cls, key, value):
         """