Python twisted.internet.defer.CancelledError() Examples

def _cancelConnectTest(self, connect):
        """
        Helper for implementing a test to verify that cancellation of the
        L{Deferred} returned by one of L{ClientCreator}'s I{connect} methods is
        implemented to cancel the underlying connector.

        @param connect: A function which will be invoked with a L{ClientCreator}
            instance as an argument and which should call one its I{connect}
            methods and return the result.

        @return: A L{Deferred} which fires when the test is complete or fails if
            there is a problem.
        """
        reactor = MemoryReactorClock()
        cc = ClientCreator(reactor, Protocol)
        d = connect(cc)
        connector = reactor.connectors.pop()
        self.assertFalse(connector._disconnected)
        d.cancel()
        self.assertTrue(connector._disconnected)
        return self.assertFailure(d, CancelledError) 

def _cancelConnectTest(self, connect):
        """
        Helper for implementing a test to verify that cancellation of the
        L{Deferred} returned by one of L{ClientCreator}'s I{connect} methods is
        implemented to cancel the underlying connector.

        @param connect: A function which will be invoked with a L{ClientCreator}
            instance as an argument and which should call one its I{connect}
            methods and return the result.

        @return: A L{Deferred} which fires when the test is complete or fails if
            there is a problem.
        """
        reactor = MemoryReactorClock()
        cc = ClientCreator(reactor, Protocol)
        d = connect(cc)
        connector = reactor.connectors.pop()
        self.assertFalse(connector._disconnected)
        d.cancel()
        self.assertTrue(connector._disconnected)
        return self.assertFailure(d, CancelledError) 

def test_cancelGetConnectionCancelsEndpointConnect(self):
        """
        Cancelling the C{Deferred} returned from
        L{HTTPConnectionPool.getConnection} cancels the C{Deferred} returned
        by opening a new connection with the given endpoint.
        """
        self.assertEqual(self.pool._connections, {})
        connectionResult = Deferred()

        class Endpoint:
            def connect(self, factory):
                return connectionResult

        d = self.pool.getConnection(12345, Endpoint())
        d.cancel()
        self.assertEqual(self.failureResultOf(connectionResult).type,
                         CancelledError) 

def test_producer_stop_during_request(self):
        """
        Test stopping producer while it's waiting for reply from client
        """
        clock = MemoryReactorClock()
        client = Mock(reactor=clock)
        f = Failure(BrokerNotAvailableError())
        ret = [fail(f), Deferred()]
        client.send_produce_request.side_effect = ret
        client.topic_partitions = {self.topic: [0, 1, 2, 3]}
        client.metadata_error_for_topic.return_value = False
        msgs = [self.msg("one"), self.msg("two")]
        batch_n = 2

        producer = Producer(client, batch_every_n=batch_n, batch_send=True)
        d = producer.send_messages(self.topic, msgs=msgs)
        # At first, there's no result. Have to retry due to first failure
        self.assertNoResult(d)
        clock.advance(producer._retry_interval)

        producer.stop()
        self.failureResultOf(d, tid_CancelledError) 

def test_producer_stop_waiting_to_retry(self):
        """
        Test stopping producer while it's waiting to retry a request
        """
        clock = MemoryReactorClock()
        client = Mock(reactor=clock)
        f = Failure(BrokerNotAvailableError())
        ret = [fail(f)]
        client.send_produce_request.side_effect = ret
        client.topic_partitions = {self.topic: [0, 1, 2, 3]}
        client.metadata_error_for_topic.return_value = False
        msgs = [self.msg("one"), self.msg("two")]
        batch_n = 2

        producer = Producer(client, batch_every_n=batch_n, batch_send=True)
        d = producer.send_messages(self.topic, msgs=msgs)
        # At first, there's no result. Have to retry due to first failure
        self.assertNoResult(d)
        # Advance the clock, some, but not enough to retry
        clock.advance(producer._retry_interval / 2)
        # Stop the producer before the retry
        producer.stop()
        self.failureResultOf(d, tid_CancelledError) 

def test_cancelConnectUNIXTimeout(self):
        """
        L{ClientCreator.connectUNIX} inserts a very short delayed call between
        the time the connection is established and the time the L{Deferred}
        returned from one of its connect methods actually fires.  If the
        L{Deferred} is cancelled in this interval, the established connection is
        closed, the timeout is cancelled, and the L{Deferred} fails with
        L{CancelledError}.
        """
        def connect(reactor, cc):
            d = cc.connectUNIX('/foo/bar')
            address, factory, timeout, bindAddress = reactor.unixClients.pop()
            protocol = factory.buildProtocol(None)
            transport = StringTransport()
            protocol.makeConnection(transport)
            return d
        return self._cancelConnectTimeoutTest(connect) 

def test_cancelConnectTCPTimeout(self):
        """
        L{ClientCreator.connectTCP} inserts a very short delayed call between
        the time the connection is established and the time the L{Deferred}
        returned from one of its connect methods actually fires.  If the
        L{Deferred} is cancelled in this interval, the established connection is
        closed, the timeout is cancelled, and the L{Deferred} fails with
        L{CancelledError}.
        """
        def connect(reactor, cc):
            d = cc.connectTCP('example.com', 1234)
            host, port, factory, timeout, bindAddress = reactor.tcpClients.pop()
            protocol = factory.buildProtocol(None)
            transport = StringTransport()
            protocol.makeConnection(transport)
            return d
        return self._cancelConnectTimeoutTest(connect) 

def test_cancelConnectSSLTimeout(self):
        """
        L{ClientCreator.connectSSL} inserts a very short delayed call between
        the time the connection is established and the time the L{Deferred}
        returned from one of its connect methods actually fires.  If the
        L{Deferred} is cancelled in this interval, the established connection is
        closed, the timeout is cancelled, and the L{Deferred} fails with
        L{CancelledError}.
        """
        def connect(reactor, cc):
            d = cc.connectSSL('example.com', 1234, object())
            host, port, factory, contextFactory, timeout, bindADdress = reactor.sslClients.pop()
            protocol = factory.buildProtocol(None)
            transport = StringTransport()
            protocol.makeConnection(transport)
            return d
        return self._cancelConnectTimeoutTest(connect) 

def test_clientConnectionFailed(self):
        """
        When a client connection fails, the service removes its reference
        to the protocol and tries again after a timeout.
        """
        clock = Clock()
        cq, service = self.makeReconnector(fireImmediately=False,
                                           clock=clock)
        self.assertEqual(len(cq.connectQueue), 1)
        cq.connectQueue[0].errback(Failure(Exception()))
        whenConnected = service.whenConnected()
        self.assertNoResult(whenConnected)
        # Don't fail during test tear-down when service shutdown causes all
        # waiting connections to fail.
        whenConnected.addErrback(lambda ignored: ignored.trap(CancelledError))
        clock.advance(AT_LEAST_ONE_ATTEMPT)
        self.assertEqual(len(cq.connectQueue), 2) 

def test_whenConnectedErrbacksOnStopService(self):
        """
        L{ClientService.whenConnected} returns a L{Deferred} that
        errbacks with L{CancelledError} if
        L{ClientService.stopService} is called between connection
        attempts.
        """
        clock = Clock()
        cq, service = self.makeReconnector(fireImmediately=False,
                                           clock=clock)
        beforeErrbackAndStop = service.whenConnected()

        # The protocol fails to connect, and the service is waiting to
        # reconnect.
        cq.connectQueue[0].errback(Exception("no connection"))

        service.stopService()
        afterErrbackAndStop = service.whenConnected()

        self.assertIsInstance(self.failureResultOf(beforeErrbackAndStop).value,
                              CancelledError)
        self.assertIsInstance(self.failureResultOf(afterErrbackAndStop).value,
                              CancelledError) 

def test_cancelAfterConnectionMade(self):
        """
        When a user cancels L{twisted.mail.smtp.sendmail} after the connection
        is made, the connection is closed by
        L{twisted.internet.interfaces.ITransport.abortConnection}.
        """
        reactor = MemoryReactor()
        transport = AbortableStringTransport()
        d = smtp.sendmail("localhost", "source@address", "recipient@address",
                          "message", reactor=reactor)
        factory = reactor.tcpClients[0][2]
        p = factory.buildProtocol(None)
        p.makeConnection(transport)
        d.cancel()
        self.assertEqual(transport.aborting, True)
        self.assertEqual(transport.disconnecting, True)
        failure = self.failureResultOf(d)
        failure.trap(defer.CancelledError) 

def test_execCancelled(self):
        """
        If execution of the command is cancelled via the L{Deferred} returned
        by L{SSHCommandClientEndpoint.connect}, the connection is closed
        immediately.
        """
        self.realm.channelLookup[b'session'] = UnsatisfiedExecSession
        endpoint = self.create()

        factory = Factory()
        factory.protocol = Protocol
        connected = endpoint.connect(factory)
        server, client, pump = self.finishConnection()

        connected.cancel()

        f = self.failureResultOf(connected)
        f.trap(CancelledError)

        self.assertClientTransportState(client, True) 

def test_cancel(self):
        """
        The L{Deferred} returned by L{task.deferLater} can be
        cancelled to prevent the call from actually being performed.
        """
        called = []
        clock = task.Clock()
        d = task.deferLater(clock, 1, called.append, None)
        d.cancel()
        def cbCancelled(ignored):
            # Make sure there are no calls outstanding.
            self.assertEqual([], clock.getDelayedCalls())
            # And make sure the call didn't somehow happen already.
            self.assertFalse(called)
        self.assertFailure(d, defer.CancelledError)
        d.addCallback(cbCancelled)
        return d 

def test_cancelDeferredListCallback(self):
        """
        When cancelling an unfired L{defer.DeferredList} without the
        C{fireOnOneCallback} and C{fireOnOneErrback} flags set, the
        L{defer.DeferredList} will be callback with a C{list} of
        (success, result) C{tuple}s.
        """
        deferredOne = defer.Deferred(fakeCallbackCanceller)
        deferredTwo = defer.Deferred()
        deferredList = defer.DeferredList([deferredOne, deferredTwo])
        deferredList.cancel()
        self.failureResultOf(deferredTwo, defer.CancelledError)
        result = self.successResultOf(deferredList)
        self.assertTrue(result[0][0])
        self.assertEqual(result[0][1], "Callback Result")
        self.assertFalse(result[1][0])
        self.assertTrue(result[1][1].check(defer.CancelledError)) 

def _complete_batch_send(self, resp):
        """Complete the processing of our batch send operation

        Clear the deferred tracking our current batch processing
        and reset our retry count and retry interval
        Return none to eat any errors coming from up the deferred chain
        """
        self._batch_send_d = None
        self._req_attempts = 0
        self._retry_interval = self._init_retry_interval
        if isinstance(resp, Failure) and not resp.check(tid_CancelledError,
                                                        CancelledError):
            log.error(
                "Failure detected in _complete_batch_send: %r", resp,
                exc_info=(resp.type, resp.value, resp.getTracebackObject()),
            )
        return 

def test_noCancellerMultipleCancelsAfterCancelAndErrback(self):
        """
        A L{defer.Deferred} without a canceller, when cancelled and then
        errbacked, ignores multiple cancels thereafter.
        """
        d = defer.Deferred()
        d.addCallbacks(self._callback, self._errback)
        d.cancel()
        self.assertEqual(self.errbackResults.type, defer.CancelledError)
        currentFailure = self.errbackResults
        # One errback will be ignored
        d.errback(GenericError())
        # I.e., we should still have a CancelledError.
        self.assertEqual(self.errbackResults.type, defer.CancelledError)
        d.cancel()
        self.assertIs(currentFailure, self.errbackResults) 

def test_cancellerMultipleCancel(self):
        """
        Verify that calling cancel multiple times on a deferred with a
        canceller that does not errback results in a
        L{defer.CancelledError} and that subsequent calls to cancel do not
        cause an error and that after all that, the canceller was only
        called once.
        """
        def cancel(d):
            self.cancellerCallCount += 1

        d = defer.Deferred(canceller=cancel)
        d.addCallbacks(self._callback, self._errback)
        d.cancel()
        self.assertEqual(self.errbackResults.type, defer.CancelledError)
        currentFailure = self.errbackResults
        d.cancel()
        self.assertIs(currentFailure, self.errbackResults)
        self.assertEqual(self.cancellerCallCount, 1) 

def test_simpleCanceller(self):
        """
        Verify that a L{defer.Deferred} calls its specified canceller when
        it is cancelled, and that further call/errbacks raise
        L{defer.AlreadyCalledError}.
        """
        def cancel(d):
            self.cancellerCallCount += 1

        d = defer.Deferred(canceller=cancel)
        d.addCallbacks(self._callback, self._errback)
        d.cancel()
        self.assertEqual(self.cancellerCallCount, 1)
        self.assertEqual(self.errbackResults.type, defer.CancelledError)

        # Test that further call/errbacks are *not* swallowed
        self.assertRaises(defer.AlreadyCalledError, d.callback, None)
        self.assertRaises(defer.AlreadyCalledError, d.errback, Exception()) 

def test_cancelNestedDeferred(self):
        """
        Verify that a Deferred, a, which is waiting on another Deferred, b,
        returned from one of its callbacks, will propagate
        L{defer.CancelledError} when a is cancelled.
        """
        def innerCancel(d):
            self.cancellerCallCount += 1
        def cancel(d):
            self.assertTrue(False)

        b = defer.Deferred(canceller=innerCancel)
        a = defer.Deferred(canceller=cancel)
        a.callback(None)
        a.addCallback(lambda data: b)
        a.cancel()
        a.addCallbacks(self._callback, self._errback)
        # The cancel count should be one (the cancellation done by B)
        self.assertEqual(self.cancellerCallCount, 1)
        # B's canceller didn't errback, so defer.py will have called errback
        # with a CancelledError.
        self.assertEqual(self.errbackResults.type, defer.CancelledError) 

def test_cancelQueueAfterGet(self):
        """
        When canceling a L{Deferred} from a L{DeferredQueue} that does not
        have a result (i.e., the L{Deferred} has not fired), the cancel
        causes a L{defer.CancelledError} failure. If the queue has a result
        later on, it doesn't try to fire the deferred.
        """
        queue = defer.DeferredQueue()
        d = queue.get()
        d.cancel()
        self.assertImmediateFailure(d, defer.CancelledError)
        def cb(ignore):
            # If the deferred is still linked with the deferred queue, it will
            # fail with an AlreadyCalledError
            queue.put(None)
            return queue.get().addCallback(self.assertIs, None)
        d.addCallback(cb)
        done = []
        d.addCallback(done.append)
        self.assertEqual(len(done), 1) 

def test_errbackAddedBeforeTimeout(self):
        """
        An errback added before a timeout is added errbacks with a
        L{defer.CancelledError} when the timeout fires.  If the
        errback returns the L{defer.CancelledError}, it is translated
        to a L{defer.TimeoutError} by the timeout implementation.
        """
        clock = Clock()
        d = defer.Deferred()

        dErrbacked = [None]

        def errback(f):
            dErrbacked[0] = f
            return f

        d.addErrback(errback)
        d.addTimeout(10, clock)

        clock.advance(15)

        self.assertIsInstance(dErrbacked[0], failure.Failure)
        self.assertIsInstance(dErrbacked[0].value, defer.CancelledError)

        self.failureResultOf(d, defer.TimeoutError) 

def test_errbackAddedBeforeTimeoutSuppressesCancellation(self):
        """
        An errback added before a timeout is added errbacks with a
        L{defer.CancelledError} when the timeout fires.  If the
        errback suppresses the L{defer.CancelledError}, the deferred
        successfully completes.
        """
        clock = Clock()
        d = defer.Deferred()

        dErrbacked = [None]

        def errback(f):
            dErrbacked[0] = f
            f.trap(defer.CancelledError)

        d.addErrback(errback)
        d.addTimeout(10, clock)

        clock.advance(15)

        self.assertIsInstance(dErrbacked[0], failure.Failure)
        self.assertIsInstance(dErrbacked[0].value, defer.CancelledError)

        self.successResultOf(d) 

def test_errbackAddedBeforeTimeoutCustom(self):
        """
        An errback added before a timeout is added with a custom
        timeout function errbacks with a L{defer.CancelledError} when
        the timeout fires.  The timeout function runs if the errback
        returns the L{defer.CancelledError}.
        """
        clock = Clock()
        d = defer.Deferred()

        dErrbacked = [None]

        def errback(f):
            dErrbacked[0] = f
            return f

        d.addErrback(errback)
        d.addTimeout(10, clock, _overrideFunc)

        clock.advance(15)

        self.assertIsInstance(dErrbacked[0], failure.Failure)
        self.assertIsInstance(dErrbacked[0].value, defer.CancelledError)

        self.assertEqual("OVERRIDDEN", self.successResultOf(d)) 

def test_errbackAddedBeforeTimeoutSuppressesCancellationCustom(self):
        """
        An errback added before a timeout is added with a custom
        timeout function errbacks with a L{defer.CancelledError} when
        the timeout fires.  The timeout function runs if the errback
        suppresses the L{defer.CancelledError}.
        """
        clock = Clock()
        d = defer.Deferred()

        dErrbacked = [None]

        def errback(f):
            dErrbacked[0] = f

        d.addErrback(errback)
        d.addTimeout(10, clock, _overrideFunc)

        clock.advance(15)

        self.assertIsInstance(dErrbacked[0], failure.Failure)
        self.assertIsInstance(dErrbacked[0].value, defer.CancelledError)

        self.assertEqual("OVERRIDDEN", self.successResultOf(d)) 

def _create_dataset(self, node):
        """
        Creates a dataset in the node given.

        :param node: node where we want the dataset.

        :return: A ``Deferred`` that fires when the dataset has been created.

        :raise DatasetCreationTimeout: if the creation goes wrong.
        """
        self.dataset_node = node
        creating = self.control_service.create_dataset(
            primary=node.uuid)

        def handle_timeout_and_errors(failure):
            failure.trap(CancelledError)
            raise DatasetCreationTimeout()

        timeout(self.reactor, creating, self.timeout)

        creating.addErrback(handle_timeout_and_errors)
        return creating 

def test_cancelGetConnectionCancelsEndpointConnect(self):
        """
        Cancelling the C{Deferred} returned from
        L{HTTPConnectionPool.getConnection} cancels the C{Deferred} returned
        by opening a new connection with the given endpoint.
        """
        self.assertEqual(self.pool._connections, {})
        connectionResult = Deferred()

        class Endpoint:
            def connect(self, factory):
                return connectionResult

        d = self.pool.getConnection(12345, Endpoint())
        d.cancel()
        self.assertEqual(self.failureResultOf(connectionResult).type,
                         CancelledError) 

def test_deprecatedTransport(self):
        """
        Calling L{client.readBody} with a transport that does not implement
        L{twisted.internet.interfaces.ITCPTransport} produces a deprecation
        warning, but no exception when cancelling.
        """
        response = DummyResponse(transportFactory=StringTransport)
        response.transport.abortConnection = None
        d = self.assertWarns(
            DeprecationWarning,
            'Using readBody with a transport that does not have an '
            'abortConnection method',
            __file__,
            lambda: client.readBody(response))
        d.cancel()
        self.failureResultOf(d, defer.CancelledError) 

def test_cancelDeferredListWithException(self):
        """
        Cancelling a L{defer.DeferredList} will cancel every L{defer.Deferred}
        in the list even exceptions raised from the C{cancel} method of the
        L{defer.Deferred}s.
        """
        def cancellerRaisesException(deferred):
            """
            A L{defer.Deferred} canceller that raises an exception.

            @param deferred: The cancelled L{defer.Deferred}.
            """
            raise RuntimeError("test")
        deferredOne = defer.Deferred(cancellerRaisesException)
        deferredTwo = defer.Deferred()
        deferredList = defer.DeferredList([deferredOne, deferredTwo])
        deferredList.cancel()
        self.failureResultOf(deferredTwo, defer.CancelledError)
        errors = self.flushLoggedErrors(RuntimeError)
        self.assertEqual(len(errors), 1) 

def test_close_while_cancelled_in_flight(self):
        """
        close() may be called when a cancelled request is in flight. The
        request is cancelled as usual and the close completes successfully.
        """
        req_d = self.brokerClient.makeRequest(2, METADATA_REQUEST_2)
        conn = self.connections.accept('*')
        conn.pump.flush()

        req_d.cancel()
        close_d = self.brokerClient.close()
        conn.pump.flush()  # Propagate connection loss.

        self.failureResultOf(req_d, defer.CancelledError)
        self.assertIs(None, self.successResultOf(close_d)) 

def test_cancelDuringResponse(self):
        """
        The L{Deferred} returned by L{HTTP11ClientProtocol.request} will fire
        with a L{ResponseFailed} failure containing a L{CancelledError}
        exception if the request was cancelled before all response headers were
        received.
        """
        transport = StringTransport()
        protocol = HTTP11ClientProtocol()
        protocol.makeConnection(transport)
        result = protocol.request(Request(b'GET', b'/', _boringHeaders, None))
        protocol.dataReceived(b"HTTP/1.1 200 OK\r\n")
        result.cancel()
        self.assertTrue(transport.disconnected)
        return assertResponseFailed(self, result, [CancelledError])