Example #1
0
class BaseWatchdogMiddleware(object):
    def __init__(self):
        self._init_timer()

    def _init_timer(self):
        self.interval = int(self._get_config().get('DOGSLOW_TIMER', 25))
        self.timer = Timer()
        self.timer.setDaemon(True)
        self.timer.start()

    def _get_config():
        raise NotImplementedError()

    def _log_to_custom_logger(self, logger_name, frame, output, req_string,
                              request):
        log_level = self._safe_get_setting('DOGSLOW_LOG_LEVEL', 'WARNING')
        log_to_sentry = self._safe_get_setting('DOGSLOW_LOG_TO_SENTRY', False)
        log_level = logging.getLevelName(log_level)
        logger = logging.getLogger(logger_name)

        # we're passing the request object along
        # with the log call in case we're being used with Sentry:
        extra = {'request': request}

        # if this is not going to Sentry, then we'll use the original msg
        if not log_to_sentry:
            msg = 'Slow Request Watchdog: %s, %s - %s' % (
                request.path,
                # resolve(request.META.get('PATH_INFO')).url_name,
                req_string.encode('utf-8'),
                output,
            )
        else:
            # if it is going to Sentry, we instead want to format differently and send more in extra
            msg, extra = self._get_message_for_sentry(frame, request, extra)
        logger.log(log_level, msg, extra=extra)

    def _safe_get_setting(self, name, default_value):
        raise NotImplementedError()

    def _get_message_for_sentry(self, frame, request, extra):
        msg = 'Slow Request Watchdog: %s' % self._get_path(request)
        module = inspect.getmodule(frame.f_code)

        # This is a bizarre construct, `module` in `function`, but
        # this is how all stack traces are formatted.
        extra['culprit'] = '%s in %s' % (module.__name__, frame.f_code.co_name)

        # We've got to simplify the stack, because raven only accepts
        # a list of 2-tuples of (frame, lineno).
        # This is a list comprehension split over a few lines.
        extra['stack'] = [(frame, lineno)
                          for frame, filename, lineno, function, code_context,
                          index in inspect.getouterframes(frame)]

        # Lastly, we have to reverse the order of the frames
        # because getouterframes() gives it to you backwards.
        extra['stack'].reverse()

        return msg, extra

    def _get_path(self, requst):
        raise NotImplementedError()

    def _compose_output(self, frame, req_string, started, thread_id):
        output = 'Undead request intercepted at: %s\n\n' \
                 '%s\n' \
                 'Hostname:   %s\n' \
                 'Thread ID:  %d\n' \
                 'Process ID: %d\n' \
                 'Started:    %s\n\n' % \
                 (dt.datetime.utcnow().strftime("%d-%m-%Y %H:%M:%S UTC"),
                  req_string,
                  socket.gethostname(),
                  thread_id,
                  os.getpid(),
                  started.strftime("%d-%m-%Y %H:%M:%S UTC"),)
        output += stack(frame, with_locals=False)
        output += '\n\n'
        stack_vars = self._safe_get_setting('DOGSLOW_STACK_VARS', False)
        if not stack_vars:
            # no local stack variables
            output += ('This report does not contain the local stack '
                       'variables.\n'
                       'To enable this (very verbose) information, add '
                       'this to your application settings:\n'
                       '  DOGSLOW_STACK_VARS = True\n')
        else:
            output += 'Full backtrace with local variables:'
            output += '\n\n'
            output += stack(frame, with_locals=True)
        return output.encode('utf-8')

    def peek(self, request, thread_id, started):
        try:
            frame = sys._current_frames()[thread_id]

            req_string = '%s %s://%s%s' % (
                request.method,
                'http',
                request.headers.get('HTTP_HOST'),
                request.path,
            )
            query_string = self._get_query_string(request)
            if query_string:
                req_string = '%s?%s' % (req_string, query_string)

            output = self._compose_output(frame, req_string, started,
                                          thread_id)

            # dump to file:
            self._dump_to_file_if_needed(output)
            # and email?
            self._send_email_if_needed(output, req_string)

            # and a custom logger:
            logger_name = self._safe_get_setting('DOGSLOW_LOGGER', None)
            if logger_name is not None:
                self._log_to_custom_logger(logger_name, frame, output,
                                           req_string, request)
        except Exception:
            logging.exception('Dogslow failed')

    def _get_query_string(self, request):
        raise NotImplementedError()

    def _dump_to_file_if_needed(self, output):
        log_to_file = self._safe_get_setting('DOGSLOW_LOG_TO_FILE', True)
        if log_to_file:
            self._log_to_file(output)

    def _log_to_file(self, output):
        fd, fn = tempfile.mkstemp(
            prefix='slow_request_',
            suffix='.log',
            dir=self._safe_get_setting('DOGSLOW_OUTPUT',
                                       tempfile.gettempdir()),
        )
        try:
            os.write(fd, output)
        finally:
            os.close(fd)

    def _send_email_if_needed(self, output, req_string):
        email_to = self._safe_get_setting('DOGSLOW_EMAIL_TO', None)
        email_from = self._safe_get_setting('DOGSLOW_EMAIL_FROM', None)

        if email_to is not None and email_from is not None:
            BaseWatchdogMiddleware._log_to_email(email_to, email_from, output,
                                                 req_string)

    @staticmethod
    def _log_to_email(email_to, email_from, output, req_string):
        raise NotImplementedError()

    def _is_exempt(self):
        raise NotImplementedError()

    def process_request(self):
        raise NotImplementedError()

    def _cancel(self, exc=None):
        raise NotImplementedError()
Example #2
0
class WatchdogMiddleware(object):

    def __init__(self):
        if not getattr(settings, 'DOGSLOW', True):
            raise MiddlewareNotUsed
        else:
            self.interval = int(getattr(settings, 'DOGSLOW_TIMER', 25))
            self.timer = Timer()
            self.timer.setDaemon(True)
            self.timer.start()

    @staticmethod
    def _log_to_custom_logger(logger_name, frame, output, req_string, request):
        log_level = getattr(settings, 'DOGSLOW_LOG_LEVEL', 'WARNING')
        log_to_sentry = getattr(settings, 'DOGSLOW_LOG_TO_SENTRY', False)
        log_level = logging.getLevelName(log_level)
        logger = logging.getLogger(logger_name)

        # we're passing the Django request object along
        # with the log call in case we're being used with
        # Sentry:
        extra = {'request': request}

        # if this is not going to Sentry,
        # then we'll use the original msg
        if not log_to_sentry:
            msg = 'Slow Request Watchdog: %s, %s - %s' % (
                resolve(request.META.get('PATH_INFO')).url_name,
                req_string.encode('utf-8'),
                output
            )

        # if it is going to Sentry,
        # we instead want to format differently and send more in extra
        else:
            msg = 'Slow Request Watchdog: %s' % request.META.get(
                'PATH_INFO')

            module = inspect.getmodule(frame.f_code)

            # This is a bizarre construct, `module` in `function`, but
            # this is how all stack traces are formatted.
            extra['culprit'] = '%s in %s' % (module.__name__,
                                             frame.f_code.co_name)

            # We've got to simplify the stack, because raven only accepts
            # a list of 2-tuples of (frame, lineno).
            # This is a list comprehension split over a few lines.
            extra['stack'] = [
                (frame, lineno)
                for frame, filename, lineno, function, code_context, index
                in inspect.getouterframes(frame)
            ]

            # Lastly, we have to reverse the order of the frames
            # because getouterframes() gives it to you backwards.
            extra['stack'].reverse()

        logger.log(log_level, msg, extra=extra)

    @staticmethod
    def _log_to_email(email_to, email_from, output, req_string):
        em = EmailMessage('Slow Request Watchdog: %s' %
                          req_string.encode('utf-8'),
                          output,
                          email_from,
                          (email_to,))
        em.send(fail_silently=True)

    @staticmethod
    def _log_to_file(output):
        fd, fn = tempfile.mkstemp(prefix='slow_request_', suffix='.log',
                                  dir=getattr(settings, 'DOGSLOW_OUTPUT',
                                              tempfile.gettempdir()))
        try:
            os.write(fd, output)
        finally:
            os.close(fd)

    @staticmethod
    def _compose_output(frame, req_string, started, thread_id):
        output = 'Undead request intercepted at: %s\n\n' \
                 '%s\n' \
                 'Hostname:   %s\n' \
                 'Thread ID:  %d\n' \
                 'Process ID: %d\n' \
                 'Started:    %s\n\n' % \
                 (dt.datetime.utcnow().strftime("%d-%m-%Y %H:%M:%S UTC"),
                  req_string,
                  socket.gethostname(),
                  thread_id,
                  os.getpid(),
                  started.strftime("%d-%m-%Y %H:%M:%S UTC"),)
        output += stack(frame, with_locals=False)
        output += '\n\n'
        stack_vars = getattr(settings, 'DOGSLOW_STACK_VARS', False)
        if not stack_vars:
            # no local stack variables
            output += ('This report does not contain the local stack '
                       'variables.\n'
                       'To enable this (very verbose) information, add '
                       'this to your Django settings:\n'
                       '  DOGSLOW_STACK_VARS = True\n')
        else:
            output += 'Full backtrace with local variables:'
            output += '\n\n'
            output += stack(frame, with_locals=True)
        return output.encode('utf-8')

    @staticmethod
    def peek(request, thread_id, started):
        try:
            frame = sys._current_frames()[thread_id]

            req_string = '%s %s://%s%s' % (
                request.META.get('REQUEST_METHOD'),
                request.META.get('wsgi.url_scheme', 'http'),
                request.META.get('HTTP_HOST'),
                request.META.get('PATH_INFO'),
            )
            if request.META.get('QUERY_STRING', ''):
                req_string += ('?' + request.META.get('QUERY_STRING'))

            output = WatchdogMiddleware._compose_output(
                frame, req_string, started, thread_id)

            # dump to file:
            log_to_file = getattr(settings, 'DOGSLOW_LOG_TO_FILE', True)
            if log_to_file:
                WatchdogMiddleware._log_to_file(output)

            # and email?
            email_to = getattr(settings, 'DOGSLOW_EMAIL_TO', None)
            email_from = getattr(settings, 'DOGSLOW_EMAIL_FROM', None)

            if email_to is not None and email_from is not None:
                WatchdogMiddleware._log_to_email(email_to, email_from,
                                                 output, req_string)
            # and a custom logger:
            logger_name = getattr(settings, 'DOGSLOW_LOGGER', None)
            if logger_name is not None:
                WatchdogMiddleware._log_to_custom_logger(
                    logger_name, frame, output, req_string, request)

        except Exception:
            logging.exception('Dogslow failed')

    def _is_exempt(self, request):
        """Returns True if this request's URL resolves to a url pattern whose
        name is listed in settings.DOGSLOW_IGNORE_URLS.
        """
        exemptions = getattr(settings, 'DOGSLOW_IGNORE_URLS', ())
        if exemptions:
            try:
                match = resolve(request.META.get('PATH_INFO'))
            except Resolver404:
                return False
            return match and (match.url_name in exemptions)
        else:
            return False

    def process_request(self, request):
        if not self._is_exempt(request):
            request.dogslow = self.timer.run_later(
                WatchdogMiddleware.peek,
                self.interval,
                request,
                thread.get_ident(),
                dt.datetime.utcnow())

    def _cancel(self, request):
        try:
            if safehasattr(request, 'dogslow'):
                self.timer.cancel(request.dogslow)
                del request.dogslow
        except Exception:
            logging.exception('Failed to cancel Dogslow timer')

    def process_response(self, request, response):
        self._cancel(request)
        return response

    def process_exception(self, request, exception):
        self._cancel(request)
Example #3
0
class WatchdogMiddleware(object):

    def __init__(self):
        if not getattr(settings, 'DOGSLOW', True):
            raise MiddlewareNotUsed
        else:
            self.interval = int(getattr(settings, 'DOGSLOW_TIMER', 25))
            self.timer = Timer()
            self.timer.setDaemon(True)
            self.timer.start()

    @staticmethod
    def peek(request, thread_id, started):
        try:
            frame = sys._current_frames()[thread_id]
            
            req_string = '%s %s://%s%s' % (
                request.META.get('REQUEST_METHOD'),
                request.META.get('wsgi.url_scheme', 'http'),
                request.META.get('HTTP_HOST'),
                request.META.get('PATH_INFO'),
            )
            if request.META.get('QUERY_STRING', ''):
                req_string += ('?' + request.META.get('QUERY_STRING'))

            output = 'Undead request intercepted at: %s\n\n' \
                '%s\n' \
                'Thread ID:  %d\n' \
                'Process ID: %d\n' \
                'Started:    %s\n\n' % \
                    (dt.datetime.utcnow().strftime("%d-%m-%Y %H:%M:%S UTC"),
                     req_string,
                     thread_id,
                     os.getpid(),
                     started.strftime("%d-%m-%Y %H:%M:%S UTC"),)

            output += stack(frame, with_locals=False)
            output += '\n\n'

            if (hasattr(settings, 'DOGSLOW_STACK_VARS')
                    and not bool(settings.DOGSLOW_STACK_VARS)):
                # no local stack variables
                output += ('This report does not contain the local stack '
                           'variables.\n'
                           'To enable this (very verbose) information, add '
                           'this to your Django settings:\n'
                           '  DOGSLOW_STACK_VARS=True\n')
            else:
                output += 'Full backtrace with local variables:'
                output += '\n\n'
                output += stack(frame, with_locals=True)

            output = output.encode('utf-8')

            # dump to file:
            fd, fn = tempfile.mkstemp(prefix='slow_request_', suffix='.log',
                                      dir=getattr(settings, 'DOGSLOW_OUTPUT',
                                              tempfile.gettempdir()))
            try:
                os.write(fd, output)
            finally:
                os.close(fd)

            # and email?
            if hasattr(settings, 'DOGSLOW_EMAIL_TO')\
                    and hasattr(settings, 'DOGSLOW_EMAIL_FROM'):
                em = EmailMessage('Slow Request Watchdog: %s' %
                                  req_string.encode('utf-8'),
                                  output,
                                  getattr(settings, 'DOGSLOW_EMAIL_FROM'),
                                  (getattr(settings, 'DOGSLOW_EMAIL_TO'),))
                em.send(fail_silently=True)

            # and a custom logger:
            if hasattr(settings, 'DOGSLOW_LOGGER'):
                logger = logging.getLogger(getattr(settings, 'DOGSLOW_LOGGER'))
                logger.warn('Slow Request Watchdog: %s, %%s - %%s' %
                            resolve(request.META.get('PATH_INFO')).url_name,
                            req_string.encode('utf-8'), output)

        except Exception:
            logging.exception('Request watchdog failed')


    def _is_exempt(self, request):
        """Returns True if this request's URL resolves to a url pattern whose
        name is listed in settings.DOGSLOW_IGNORE_URLS.
        """
        match = resolve(request.META.get('PATH_INFO'))
        return match and (match.url_name in
                       getattr(settings, 'DOGSLOW_IGNORE_URLS', ()))

    def process_request(self, request):
        if not self._is_exempt(request):
            request.dogslow = self.timer.run_later(
                WatchdogMiddleware.peek,
                self.interval,
                request,
                thread.get_ident(),
                dt.datetime.utcnow())

    def _cancel(self, request):
        try:
            if hasattr(request, 'dogslow'):
                self.timer.cancel(request.dogslow)
                del request.dogslow
        except:
            logging.exception('Failed to cancel request watchdog')

    def process_response(self, request, response):
        self._cancel(request)
        return response

    def process_exception(self, request, exception):
        self._cancel(request)
Example #4
0
class WatchdogMiddleware(object):

    def __init__(self):
        if not getattr(settings, 'DOGSLOW', True):
            raise MiddlewareNotUsed
        else:
            self.interval = int(getattr(settings, 'DOGSLOW_TIMER', 25))
            self.timer = Timer()
            self.timer.setDaemon(True)
            self.timer.start()

    @staticmethod
    def _log_to_custom_logger(logger_name, frame, output, req_string, request):
        log_level = getattr(settings, 'DOGSLOW_LOG_LEVEL', 'WARNING')
        log_to_sentry = getattr(settings, 'DOGSLOW_LOG_TO_SENTRY', False)
        log_level = logging.getLevelName(log_level)
        logger = logging.getLogger(logger_name)

        # we're passing the Django request object along
        # with the log call in case we're being used with
        # Sentry:
        extra = {'request': request}

        # if this is not going to Sentry,
        # then we'll use the original msg
        if not log_to_sentry:
            msg = 'Slow Request Watchdog: %s - %s' % (
                req_string,
                output
            )

        # if it is going to Sentry,
        # we instead want to format differently and send more in extra
        else:
            msg = 'Slow Request Watchdog: %s' % request.META.get(
                'PATH_INFO')

            module = inspect.getmodule(frame.f_code)

            # This is a bizarre construct, `module` in `function`, but
            # this is how all stack traces are formatted.
            extra['culprit'] = '%s in %s' % (
                getattr(module, '__name__', '(unknown module)'),
                frame.f_code.co_name)

            # We've got to simplify the stack, because raven only accepts
            # a list of 2-tuples of (frame, lineno).
            # This is a list comprehension split over a few lines.
            extra['stack'] = [
                (frame, lineno)
                for frame, filename, lineno, function, code_context, index
                in inspect.getouterframes(frame)
            ]

            # Lastly, we have to reverse the order of the frames
            # because getouterframes() gives it to you backwards.
            extra['stack'].reverse()

        logger.log(log_level, msg, extra=extra)

    @staticmethod
    def _log_to_email(email_to, email_from, output, req_string):
        if hasattr(email_to, 'split'):
            # Looks like a string, but EmailMessage expects a sequence.
            email_to = (email_to,)
        em = EmailMessage('Slow Request Watchdog: %s' %
                          req_string,
                          output.decode('utf-8', 'replace'),
                          email_from,
                          email_to)
        em.send(fail_silently=True)

    @staticmethod
    def _log_to_file(output):
        fd, fn = tempfile.mkstemp(prefix='slow_request_', suffix='.log',
                                  dir=getattr(settings, 'DOGSLOW_OUTPUT',
                                              tempfile.gettempdir()))
        try:
            os.write(fd, output)
        finally:
            os.close(fd)

    @staticmethod
    def _compose_output(frame, req_string, started, thread_id):
        output = 'Undead request intercepted at: %s\n\n' \
                 '%s\n' \
                 'Hostname:   %s\n' \
                 'Thread ID:  %d\n' \
                 'Process ID: %d\n' \
                 'Started:    %s\n\n' % \
                 (dt.datetime.utcnow().strftime("%d-%m-%Y %H:%M:%S UTC"),
                  req_string,
                  socket.gethostname(),
                  thread_id,
                  os.getpid(),
                  started.strftime("%d-%m-%Y %H:%M:%S UTC"),)
        output += stack(frame, with_locals=False)
        output += '\n\n'
        stack_vars = getattr(settings, 'DOGSLOW_STACK_VARS', False)
        if not stack_vars:
            # no local stack variables
            output += ('This report does not contain the local stack '
                       'variables.\n'
                       'To enable this (very verbose) information, add '
                       'this to your Django settings:\n'
                       '  DOGSLOW_STACK_VARS = True\n')
        else:
            output += 'Full backtrace with local variables:'
            output += '\n\n'
            output += stack(frame, with_locals=True)
        return output

    @staticmethod
    def peek(request, thread_id, started):
        try:
            frame = sys._current_frames()[thread_id]

            req_string = '%s %s' % (
                request.META.get('REQUEST_METHOD'),
                request.META.get('PATH_INFO'),
            )
            if request.META.get('QUERY_STRING', ''):
                req_string += ('?' + request.META.get('QUERY_STRING'))

            output = WatchdogMiddleware._compose_output(
                frame, req_string, started, thread_id)

            # dump to file:
            log_to_file = getattr(settings, 'DOGSLOW_LOG_TO_FILE', True)
            if log_to_file:
                WatchdogMiddleware._log_to_file(output)

            # and email?
            email_to = getattr(settings, 'DOGSLOW_EMAIL_TO', None)
            email_from = getattr(settings, 'DOGSLOW_EMAIL_FROM', None)

            if email_to is not None and email_from is not None:
                WatchdogMiddleware._log_to_email(email_to, email_from,
                                                 output, req_string)
            # and a custom logger:
            logger_name = getattr(settings, 'DOGSLOW_LOGGER', None)
            if logger_name is not None:
                WatchdogMiddleware._log_to_custom_logger(
                    logger_name, frame, output, req_string, request)

        except Exception:
            logging.exception('Dogslow failed')

    def _is_exempt(self, request):
        """Returns True if this request's URL resolves to a url pattern whose
        name is listed in settings.DOGSLOW_IGNORE_URLS.
        """
        exemptions = getattr(settings, 'DOGSLOW_IGNORE_URLS', ())
        if exemptions:
            try:
                match = resolve(request.META.get('PATH_INFO'))
            except Resolver404:
                return False
            return match and (match.url_name in exemptions)
        else:
            return False

    def process_request(self, request):
        if not self._is_exempt(request):
            request.dogslow = self.timer.run_later(
                WatchdogMiddleware.peek,
                self.interval,
                request,
                thread.get_ident(),
                dt.datetime.utcnow())

    def _cancel(self, request):
        try:
            if safehasattr(request, 'dogslow'):
                self.timer.cancel(request.dogslow)
                del request.dogslow
        except Exception:
            logging.exception('Failed to cancel Dogslow timer')

    def process_response(self, request, response):
        self._cancel(request)
        return response

    def process_exception(self, request, exception):
        self._cancel(request)
Example #5
0
class WatchdogMiddleware(object):
    def __init__(self):
        if not getattr(settings, "DOGSLOW", True):
            raise MiddlewareNotUsed
        else:
            # allow floating points to cater for millisecond precision
            self.interval = float(getattr(settings, "DOGSLOW_TIMER", 25))
            self.timer = Timer()
            self.timer.setDaemon(True)
            self.timer.start()

    @staticmethod
    def peek(request, thread_id, started):
        try:
            frame = sys._current_frames()[thread_id]

            req_string = "%s %s://%s%s" % (
                request.META.get("REQUEST_METHOD"),
                request.META.get("wsgi.url_scheme", "http"),
                request.META.get("HTTP_HOST"),
                request.META.get("PATH_INFO"),
            )
            if request.META.get("QUERY_STRING", ""):
                req_string += "?" + request.META.get("QUERY_STRING")

            output = (
                "Undead request intercepted at: %s\n\n"
                "%s\n"
                "Hostname:   %s\n"
                "Thread ID:  %d\n"
                "Process ID: %d\n"
                "Started:    %s\n\n"
                % (
                    dt.datetime.utcnow().strftime("%d-%m-%Y %H:%M:%S UTC"),
                    req_string,
                    socket.gethostname(),
                    thread_id,
                    os.getpid(),
                    started.strftime("%d-%m-%Y %H:%M:%S UTC"),
                )
            )

            output += stack(frame, with_locals=False)
            output += "\n\n"

            stack_vars = getattr(settings, "DOGSLOW_STACK_VARS", False)
            if not stack_vars:
                # no local stack variables
                output += (
                    "This report does not contain the local stack "
                    "variables.\n"
                    "To enable this (very verbose) information, add "
                    "this to your Django settings:\n"
                    "  DOGSLOW_STACK_VARS=True\n"
                )
            else:
                output += "Full backtrace with local variables:"
                output += "\n\n"
                output += stack(frame, with_locals=True)

            output = output.encode("utf-8")

            # Default to None to allow local logs to be omitted
            local_path = getattr(settings, "DOGSLOW_OUTPUT", None)

            if local_path is not None:
                # dump to file:
                fd = tempfile.mkstemp(prefix="slow_request_", suffix=".log", dir=local_path)
                try:
                    os.write(fd, output)
                finally:
                    os.close(fd)

            # and email?
            email_to = getattr(settings, "DOGSLOW_EMAIL_TO", None)
            email_from = getattr(settings, "DOGSLOW_EMAIL_FROM", None)
            if email_to is not None and email_from is not None:
                em = EmailMessage(
                    "Slow Request Watchdog: %s" % req_string.encode("utf-8"), output, email_from, (email_to,)
                )
                em.send(fail_silently=True)

            # and a custom logger:
            logger_name = getattr(settings, "DOGSLOW_LOGGER", None)
            log_level = getattr(settings, "DOGSLOW_LOG_LEVEL", "WARNING")
            if logger_name is not None:
                log_level = logging.getLevelName(log_level)
                logger = logging.getLogger(logger_name)

                logger.log(
                    log_level,
                    "Slow Request Watchdog: %s, %s - %s",
                    resolve(request.META.get("PATH_INFO")).url_name,
                    req_string.encode("utf-8"),
                    output,
                    # we're passing the Django request object along
                    # with the log call in case we're being used with
                    # Sentry:
                    extra={"request": request},
                )

        except Exception:
            logging.exception("Request watchdog failed")

    def _is_exempt(self, request):
        """Returns True if this request's URL resolves to a url pattern whose
        name is listed in settings.DOGSLOW_IGNORE_URLS.
        """
        try:
            match = resolve(request.META.get("PATH_INFO"))
        except Resolver404:
            return False
        return match and (match.url_name in getattr(settings, "DOGSLOW_IGNORE_URLS", ()))

    def process_request(self, request):
        if not self._is_exempt(request):
            request.dogslow = self.timer.run_later(
                WatchdogMiddleware.peek, self.interval, request, thread.get_ident(), dt.datetime.utcnow()
            )

    def _cancel(self, request):
        try:
            if safehasattr(request, "dogslow"):
                self.timer.cancel(request.dogslow)
                del request.dogslow
        except:
            logging.exception("Failed to cancel request watchdog")

    def process_response(self, request, response):
        self._cancel(request)
        return response

    def process_exception(self, request, exception):
        self._cancel(request)