check the python requirements for the gaiohttp server

fix #788

docs/source/news.rst

@@ -9,6 +9,7 @@ Changes
 Core
 ++++
 
+- improvement: fix #788 check the python requirements for the gaiohttp server
 - fix #785: handle binary type address given to a client socket address
 - fix graceful shutdown. make sure QUIT and TERMS signals are switched
   everywhere.
@@ -19,7 +20,7 @@ Tornado worker
 - fix #783: x_headers error. The x-forwarded-headers option has been removed
   in `c4873681299212d6082cd9902740eef18c2f14f1
   <https://github.com/benoitc/gunicorn/commit/c4873681299212d6082cd9902740eef18c2f14f1>`_. The discussion is
-  available on `#633 <https://github.com/benoitc/gunicorn/pull/633>`_. 
+  available on `#633 <https://github.com/benoitc/gunicorn/pull/633>`_.
 
 
 

gunicorn/workers/gaiohttp.py

@@ -7,7 +7,12 @@ __all__ = ['AiohttpWorker']
 import asyncio
 import functools
 import os
-import gunicorn.workers.base as base
+import sys
+
+from . import base
+
+if sys.version_info < (3, 3, 0):
+    raise RuntimeError("Python 3.3 and later is needed to run this worker")
 
 try:
     from aiohttp.wsgi import WSGIServerHttpProtocol