Catch exceptions when sending GoAway frame

Implement stylistic changes to the warnin messages. Use a valid endpoint stream identifier for the unexpected stream id test. Catch any exception when sending the GoAway frame during graceful shutdown. We can only do our best to send the GoAway frame as specified in the spec.

Author: jdecuyper

hyper/http20/connection.py

@@ -246,7 +246,12 @@ def close(self):
             stream.close()
 
         # Send GoAway frame to the server
-        self._send_cb(GoAwayFrame(0), True)
+        try:
+           self._send_cb(GoAwayFrame(0), True)
+        except:
+           log.warn(
+              "GoAway frame could not be sent: %s" % sys.exc_info()[0]
+           )
 
         if self._sock is not None:
             self._sock.close()
@@ -593,8 +598,9 @@ def _consume_frame_payload(self, frame, data):
                 f = RstStreamFrame(frame.stream_id)
                 f.error_code = 1 # PROTOCOL_ERROR
                 self._send_cb(f)
-                log.warning("Unexpected stream identifier %d" %
-                               (frame.stream_id))
+                log.warning(
+                    "Unexpected stream identifier %d" % (frame.stream_id)
+                )
         else:
             self.receive_frame(frame)
 

test/test_hyper.py

@@ -1270,15 +1270,15 @@ def data_callback(frame):
         c = HTTP20Connection('www.google.com')
         c._send_cb = data_callback
 
-        f = DataFrame(-1)
+        f = DataFrame(2)
         data = memoryview(b"hi there sir")
         c._consume_frame_payload(f, data)
 
         # If we receive an unexpected stream id then we cancel the stream
         # by sending a reset stream that contains the protocol error code (1)
         f = frames[0]
         assert len(frames) == 1
-        assert f.stream_id == -1
+        assert f.stream_id == 2
         assert isinstance(f, RstStreamFrame)
         assert f.error_code == 1 # PROTOCOL_ERROR