ASGI lifespan failure on exception (#2627)

sanic/asgi.py

@@ -9,7 +9,7 @@ from sanic.compat import Header
 from sanic.exceptions import ServerError
 from sanic.helpers import Default
 from sanic.http import Stage
-from sanic.log import logger
+from sanic.log import error_logger, logger
 from sanic.models.asgi import ASGIReceive, ASGIScope, ASGISend, MockTransport
 from sanic.request import Request
 from sanic.response import BaseHTTPResponse
@@ -85,13 +85,27 @@ class Lifespan:
     ) -> None:
         message = await receive()
         if message["type"] == "lifespan.startup":
-            await self.startup()
-            await send({"type": "lifespan.startup.complete"})
+            try:
+                await self.startup()
+            except Exception as e:
+                error_logger.exception(e)
+                await send(
+                    {"type": "lifespan.startup.failed", "message": str(e)}
+                )
+            else:
+                await send({"type": "lifespan.startup.complete"})
 
         message = await receive()
         if message["type"] == "lifespan.shutdown":
-            await self.shutdown()
-            await send({"type": "lifespan.shutdown.complete"})
+            try:
+                await self.shutdown()
+            except Exception as e:
+                error_logger.exception(e)
+                await send(
+                    {"type": "lifespan.shutdown.failed", "message": str(e)}
+                )
+            else:
+                await send({"type": "lifespan.shutdown.complete"})
 
 
 class ASGIApp: