Event autoregister (#2140)

* Add event autoregistration

* Setup tests

* Cleanup IDE added imports

* Remove unused imports

sanic/app.py

@@ -382,11 +382,19 @@ class Sanic(BaseSanic):
             condition=condition,
         )
 
-    def event(self, event: str, timeout: Optional[Union[int, float]] = None):
+    async def event(
+        self, event: str, timeout: Optional[Union[int, float]] = None
+    ):
         signal = self.signal_router.name_index.get(event)
         if not signal:
-            raise NotFound("Could not find signal %s" % event)
-        return wait_for(signal.ctx.event.wait(), timeout=timeout)
+            if self.config.EVENT_AUTOREGISTER:
+                self.signal_router.reset()
+                self.add_signal(None, event)
+                signal = self.signal_router.name_index.get(event)
+                self.signal_router.finalize()
+            else:
+                raise NotFound("Could not find signal %s" % event)
+        return await wait_for(signal.ctx.event.wait(), timeout=timeout)
 
     def enable_websocket(self, enable=True):
         """Enable or disable the support for websocket.

sanic/config.py

@@ -16,28 +16,29 @@ BASE_LOGO = """
 """
 
 DEFAULT_CONFIG = {
-    "REQUEST_MAX_SIZE": 100000000,  # 100 megabytes
+    "ACCESS_LOG": True,
+    "EVENT_AUTOREGISTER": False,
+    "FALLBACK_ERROR_FORMAT": "html",
+    "FORWARDED_FOR_HEADER": "X-Forwarded-For",
+    "FORWARDED_SECRET": None,
+    "GRACEFUL_SHUTDOWN_TIMEOUT": 15.0,  # 15 sec
+    "KEEP_ALIVE_TIMEOUT": 5,  # 5 seconds
+    "KEEP_ALIVE": True,
+    "PROXIES_COUNT": None,
+    "REAL_IP_HEADER": None,
+    "REGISTER": True,
     "REQUEST_BUFFER_QUEUE_SIZE": 100,
     "REQUEST_BUFFER_SIZE": 65536,  # 64 KiB
+    "REQUEST_ID_HEADER": "X-Request-ID",
+    "REQUEST_MAX_SIZE": 100000000,  # 100 megabytes
     "REQUEST_TIMEOUT": 60,  # 60 seconds
     "RESPONSE_TIMEOUT": 60,  # 60 seconds
-    "KEEP_ALIVE": True,
-    "KEEP_ALIVE_TIMEOUT": 5,  # 5 seconds
-    "WEBSOCKET_MAX_SIZE": 2 ** 20,  # 1 megabyte
     "WEBSOCKET_MAX_QUEUE": 32,
+    "WEBSOCKET_MAX_SIZE": 2 ** 20,  # 1 megabyte
+    "WEBSOCKET_PING_INTERVAL": 20,
+    "WEBSOCKET_PING_TIMEOUT": 20,
     "WEBSOCKET_READ_LIMIT": 2 ** 16,
     "WEBSOCKET_WRITE_LIMIT": 2 ** 16,
-    "WEBSOCKET_PING_TIMEOUT": 20,
-    "WEBSOCKET_PING_INTERVAL": 20,
-    "GRACEFUL_SHUTDOWN_TIMEOUT": 15.0,  # 15 sec
-    "ACCESS_LOG": True,
-    "FORWARDED_SECRET": None,
-    "REAL_IP_HEADER": None,
-    "PROXIES_COUNT": None,
-    "FORWARDED_FOR_HEADER": "X-Forwarded-For",
-    "REQUEST_ID_HEADER": "X-Request-ID",
-    "FALLBACK_ERROR_FORMAT": "html",
-    "REGISTER": True,
 }
 
 

sanic/mixins/signals.py

@@ -1,4 +1,4 @@
-from typing import Any, Callable, Dict, Set
+from typing import Any, Callable, Dict, Optional, Set
 
 from sanic.models.futures import FutureSignal
 from sanic.models.handler_types import SignalHandler
@@ -60,10 +60,16 @@ class SignalMixin:
 
     def add_signal(
         self,
-        handler,
+        handler: Optional[Callable[..., Any]],
         event: str,
         condition: Dict[str, Any] = None,
     ):
+        if not handler:
+
+            async def noop():
+                ...
+
+            handler = noop
         self.signal(event=event, condition=condition)(handler)
         return handler