tools (utils): Add aio_func attribute to @aio decorated methods:

We sometimes to need to call another method in asyncio context when we already are in this
context. With the `@aio` decorator which makes the method return a `Deferred`, it was
necessary to use a ping pong between `Deferred` and `Future`.
This patch adds a `aio_func` attribute which directly returns the wrapped asyncio method,
so it can now be awaited directly.

libervia/backend/memory/sqla.py

@@ -1254,25 +1254,23 @@ class Storage:
             if create_kwargs is None:
                 create_kwargs = {}
             try:
-                return await as_future(
-                    self.set_pubsub_node(client, service, name, **create_kwargs)
+                return await self.set_pubsub_node.aio_func(
+                    client, service, name, **create_kwargs
                 )
             except IntegrityError as e:
                 if "unique" in str(e.orig).lower():
                     # the node may already exist, if it has been created just after
                     # get_pubsub_node above
                     log.debug("ignoring UNIQUE constraint error")
-                    return await as_future(
-                        self.get_pubsub_node(
-                            client,
-                            service,
-                            name=name,
-                            with_items=with_items,
-                            with_subscriptions=with_subscriptions,
-                            with_affiliations=with_affiliations,
-                            with_parent=with_parent,
-                            with_link=with_link,
-                        )
+                    return await self.get_pubsub_node.aio_func(
+                        client,
+                        service,
+                        name=name,
+                        with_items=with_items,
+                        with_subscriptions=with_subscriptions,
+                        with_affiliations=with_affiliations,
+                        with_parent=with_parent,
+                        with_link=with_link,
                     )
                 else:
                     raise e
@@ -2059,7 +2057,7 @@ class Storage:
             If affiliation is None, the entity's affiliation is removed.
         @raise exceptions.NotFound: Node doesn't exist.
         """
-        node = await as_future(self.get_pubsub_node(client, service, node_name))
+        node = await self.get_pubsub_node.aio_func(client, service, node_name)
         if node is None:
             raise exceptions.NotFound(f"Node {node_name!r} not found")
 

libervia/backend/tools/utils.py

@@ -18,7 +18,7 @@
 
 """various useful methods"""
 
-from typing import Any, Optional, Union
+from typing import Any, Callable, Optional, Union
 import unicodedata
 import os.path
 import datetime
@@ -134,15 +134,20 @@ async def maybe_async(ret: Any) -> Any:
     return ret
 
 
-def aio(func):
-    """Decorator to return a Deferred from asyncio coroutine
+def aio(func: Callable[..., Any]) -> Callable[..., Any]:
+    """Decorator to return a Deferred from asyncio coroutine.
 
-    Functions with this decorator are run in asyncio context
+    Functions with this decorator are run in asyncio context.
+
+    The original coroutine is exposed as func.aio_func for direct awaiting (e.g. when
+    called from another @aio function to avoid spawning an extra task via ensure_future).
     """
 
-    def wrapper(*args, **kwargs):
+    @functools.wraps(func)
+    def wrapper(*args: Any, **kwargs: Any) -> defer.Deferred:
         return defer.Deferred.fromFuture(asyncio.ensure_future(func(*args, **kwargs)))
 
+    wrapper.aio_func = func  # type: ignore
     return wrapper