Add a new exception signal for ALL exceptions raised anywhere in application (#2724)

sanic/app.py

@@ -773,6 +773,10 @@ class Sanic(StaticHandleMixin, BaseSanic, StartupMixin, metaclass=TouchUpMeta):
         :raises ServerError: response 500
         """
         response = None
+        await self.dispatch(
+            "server.lifecycle.exception",
+            context={"exception": exception},
+        )
         await self.dispatch(
             "http.lifecycle.exception",
             inline=True,

sanic/handlers/error.py

@@ -6,7 +6,9 @@ from sanic.errorpages import BaseRenderer, TextRenderer, exception_response
 from sanic.exceptions import ServerError
 from sanic.log import error_logger
 from sanic.models.handler_types import RouteHandler
+from sanic.request.types import Request
 from sanic.response import text
+from sanic.response.types import HTTPResponse
 
 
 class ErrorHandler:
@@ -148,7 +150,7 @@ class ErrorHandler:
                 return text("An error occurred while handling an error", 500)
         return response
 
-    def default(self, request, exception):
+    def default(self, request: Request, exception: Exception) -> HTTPResponse:
         """
         Provide a default behavior for the objects of :class:`ErrorHandler`.
         If a developer chooses to extent the :class:`ErrorHandler` they can

sanic/signals.py

@@ -20,6 +20,7 @@ class Event(Enum):
     SERVER_INIT_BEFORE = "server.init.before"
     SERVER_SHUTDOWN_AFTER = "server.shutdown.after"
     SERVER_SHUTDOWN_BEFORE = "server.shutdown.before"
+    SERVER_LIFECYCLE_EXCEPTION = "server.lifecycle.exception"
     HTTP_LIFECYCLE_BEGIN = "http.lifecycle.begin"
     HTTP_LIFECYCLE_COMPLETE = "http.lifecycle.complete"
     HTTP_LIFECYCLE_EXCEPTION = "http.lifecycle.exception"
@@ -43,6 +44,7 @@ RESERVED_NAMESPACES = {
         Event.SERVER_INIT_BEFORE.value,
         Event.SERVER_SHUTDOWN_AFTER.value,
         Event.SERVER_SHUTDOWN_BEFORE.value,
+        Event.SERVER_LIFECYCLE_EXCEPTION.value,
     ),
     "http": (
         Event.HTTP_LIFECYCLE_BEGIN.value,
@@ -168,6 +170,16 @@ class SignalRouter(BaseRouter):
                     elif maybe_coroutine:
                         return maybe_coroutine
             return None
+        except Exception as e:
+            if self.ctx.app.debug and self.ctx.app.state.verbosity >= 1:
+                error_logger.exception(e)
+
+            if event != Event.SERVER_LIFECYCLE_EXCEPTION.value:
+                await self.dispatch(
+                    Event.SERVER_LIFECYCLE_EXCEPTION.value,
+                    context={"exception": e},
+                )
+            raise e
         finally:
             for signal_event in events:
                 signal_event.clear()