def __init__(self, app, router, service_name):
        """
        :param service_name: Service name (e.g. api, stream, auth).
        :type service_name: ``str``
        """
        self.app = app
        self.router = router
        self._service_name = service_name

        :param service_name: Service name (e.g. api, stream, auth).
        :type service_name: ``str``
        
st2common/st2common/middleware/instrumentation.py