Commit 3ef354d8 authored by Jim Newsome's avatar Jim Newsome
Browse files

Traffic.py: improve timeout/cancellation behavior 

* In the various `wait_done` methods, don't await potentially-cancelled
  tasks. Awaiting cancelled tasks in python is generally considered bad
  practice, and more concretely it's tricky to correctly determine
  whether a caught CancelledError while awaiting such a task is a result
  of *our* task being cancelled, in which case it should be re-raised.
  Previously we were swallowing these, which may have prevented the rest
  of cancellation from being handled properly.

  For these what we really care about are that the sockets are fully
  closed, so we just await that directly.

* In places where we want to catch and re-raise all exceptions, use
  BaseException instead of Exception. In particular CancelledError is a
  BaseException but not an Exception.

This fixes the asyncio warnings about un-retrieved task errors after the
test times out and is cancelled.
parent 6d13df1e

lib/chutney/Traffic.py

+10 −36
Original line number Diff line number Diff line
@@ -197,7 +197,7 @@ class Listener(object): 
                family=addr_to_family(self._endpoint[0]),

            )

            self._server.set_result(server)

        except Exception as e:

        except BaseException as e:

            self._server.set_exception(e)

            raise

        await server.serve_forever()
@@ -220,17 +220,13 @@ class Listener(object): 
        """Start closing"""

        # Clean up, and ensure we don't create the server if we haven't already.

        self._task.cancel()

        if self._server.done():

        if self._server.done() and self._server.exception() is None:

            server = self._server.result()

            server.close()



    async def wait_closed(self) -> None:

        """Wait for close to complete"""

        try:

            await self._task

        except asyncio.CancelledError:

            pass

        if self._server.done():

        """Wait for listening socket to be closed"""

        if self._server.done() and self._server.exception() is None:

            server = self._server.result()

            await server.wait_closed()
@@ -337,10 +333,6 @@ class EchoServer(object): 


    async def wait_closed(self) -> None:

        """Wait for close to complete"""

        try:

            await self._run_task

        except asyncio.CancelledError:

            pass

        await self._writer.wait_closed()
@@ -377,7 +369,7 @@ class EchoClient(object): 
                )

                self._reader.set_result(reader)

                self._writer.set_result(writer)

            except Exception as e:

            except BaseException as e:

                self._reader.set_exception(e)

                self._writer.set_exception(e)

                raise
@@ -493,17 +485,13 @@ class EchoClient(object): 


    def abort(self) -> None:

        self._run_task.cancel()

        if self._writer.done():

        if self._writer.done() and self._writer.exception() is None:

            writer = self._writer.result()

            writer.transport.abort()

            writer.close()



    async def wait_closed(self) -> None:

        try:

            await self._run_task

        except asyncio.CancelledError:

            pass

        if self._writer.done():

        if self._writer.done() and self._writer.exception is None:

            await self._writer.result().wait_closed()



    async def fileno(self) -> int:
@@ -634,27 +622,13 @@ class TrafficTester(object): 
        # TODO: Unfortunately we still get ADDRINUSE when retrying under shadow.

        for r in self.responders:

            r.abort()

            try:

            await r.wait_closed()

            except Exception as e:

                logger.info("Failure: Waiting for responder, got exception: %s", e)

                res = False

        for c in self.clients:

            c.abort()

            try:

            await c.wait_closed()

            except Exception as e:

                logger.info(

                    "Failure: Waiting for client %s, got exception: %s", c.name, e

                )

                res = False

        if self.listener is not None:

            self.listener.close()

            try:

            await self.listener.wait_closed()

            except Exception as e:

                logger.info("Failure: Waiting for listener, got exception: %s", e)

                res = False



        return res