better logging on http parse errors

NoMoreData now inherits StopIteration and the StopIteration clause in
the workers logs the reason at debug level.

gunicorn/http/errors.py

@@ -6,7 +6,7 @@
 class ParseException(Exception):
     pass
 
-class NoMoreData(ParseException):
+class NoMoreData(ParseException, StopIteration):
     def __init__(self, buf=None):
         self.buf = buf
     def __str__(self):

gunicorn/workers/async.py

@@ -36,8 +36,8 @@ class AsyncWorker(base.Worker):
                     if not req:
                         break
                     self.handle_request(req, client, addr)
-            except StopIteration:
-                pass
+            except StopIteration, e:
+                self.log.debug("Closing connection. %s", e)
         except socket.error, e:
             if e[0] not in (errno.EPIPE, errno.ECONNRESET):
                 self.log.exception("Socket error processing request.")

gunicorn/workers/sync.py

@@ -69,8 +69,8 @@ class SyncWorker(base.Worker):
             parser = http.RequestParser(client)
             req = parser.next()
             self.handle_request(req, client, addr)
-        except StopIteration:
-            self.log.debug("Ignored premature client disconnection.")
+        except StopIteration, e:
+            self.log.debug("Closing connection. %s", e)
         except socket.error, e:
             if e[0] != errno.EPIPE:
                 self.log.exception("Error processing request.")