Add convenience method for exception reporting (#2792)

sanic/app.py

@@ -17,7 +17,7 @@ from asyncio import (
 from asyncio.futures import Future
 from collections import defaultdict, deque
 from contextlib import contextmanager, suppress
-from functools import partial
+from functools import partial, wraps
 from inspect import isawaitable
 from os import environ
 from socket import socket
@@ -87,7 +87,7 @@ from sanic.request import Request
 from sanic.response import BaseHTTPResponse, HTTPResponse, ResponseStream
 from sanic.router import Router
 from sanic.server.websockets.impl import ConnectionClosed
-from sanic.signals import Signal, SignalRouter
+from sanic.signals import Event, Signal, SignalRouter
 from sanic.touchup import TouchUp, TouchUpMeta
 from sanic.types.shared_ctx import SharedContext
 from sanic.worker.inspector import Inspector
@@ -605,6 +605,19 @@ class Sanic(
                 raise NotFound("Could not find signal %s" % event)
         return await wait_for(signal.ctx.event.wait(), timeout=timeout)
 
+    def report_exception(
+        self, handler: Callable[[Sanic, Exception], Coroutine[Any, Any, None]]
+    ):
+        @wraps(handler)
+        async def report(exception: Exception) -> None:
+            await handler(self, exception)
+
+        self.add_signal(
+            handler=report, event=Event.SERVER_EXCEPTION_REPORT.value
+        )
+
+        return report
+
     def enable_websocket(self, enable=True):
         """Enable or disable the support for websocket.
 
@@ -876,10 +889,12 @@ class Sanic(
         :raises ServerError: response 500
         """
         response = None
-        await self.dispatch(
-            "server.lifecycle.exception",
-            context={"exception": exception},
-        )
+        if not getattr(exception, "__dispatched__", False):
+            ...  # DO NOT REMOVE THIS LINE. IT IS NEEDED FOR TOUCHUP.
+            await self.dispatch(
+                "server.exception.report",
+                context={"exception": exception},
+            )
         await self.dispatch(
             "http.lifecycle.exception",
             inline=True,
@@ -1310,13 +1325,28 @@ class Sanic(
         app,
         loop,
     ):
-        if callable(task):
+        async def do(task):
             try:
-                task = task(app)
-            except TypeError:
-                task = task()
+                if callable(task):
+                    try:
+                        task = task(app)
+                    except TypeError:
+                        task = task()
+                if isawaitable(task):
+                    await task
+            except CancelledError:
+                error_logger.warning(
+                    f"Task {task} was cancelled before it completed."
+                )
+                raise
+            except Exception as e:
+                await app.dispatch(
+                    "server.exception.report",
+                    context={"exception": e},
+                )
+                raise
 
-        return task
+        return do(task)
 
     @classmethod
     def _loop_add_task(

sanic/signals.py

@@ -16,11 +16,11 @@ from sanic.models.handler_types import SignalHandler
 
 
 class Event(Enum):
+    SERVER_EXCEPTION_REPORT = "server.exception.report"
     SERVER_INIT_AFTER = "server.init.after"
     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"
@@ -40,11 +40,11 @@ class Event(Enum):
 
 RESERVED_NAMESPACES = {
     "server": (
+        Event.SERVER_EXCEPTION_REPORT.value,
         Event.SERVER_INIT_AFTER.value,
         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,
@@ -174,11 +174,12 @@ class SignalRouter(BaseRouter):
             if self.ctx.app.debug and self.ctx.app.state.verbosity >= 1:
                 error_logger.exception(e)
 
-            if event != Event.SERVER_LIFECYCLE_EXCEPTION.value:
+            if event != Event.SERVER_EXCEPTION_REPORT.value:
                 await self.dispatch(
-                    Event.SERVER_LIFECYCLE_EXCEPTION.value,
+                    Event.SERVER_EXCEPTION_REPORT.value,
                     context={"exception": e},
                 )
+                setattr(e, "__dispatched__", True)
             raise e
         finally:
             for signal_event in events: