async event listener

fantix · fantix · commit ae620b1a7a4a · 2021-03-20T23:25:50.000-04:00
diff --git a/lib/sqlalchemy/event/api.py b/lib/sqlalchemy/event/api.py
@@ -96,6 +96,17 @@ def on_config():
 
     """
 
+    if util.concurrency.iscoroutinefunction(fn):
+        await_ = (
+            util.concurrency.await_fallback
+            if kw.pop("async_fallback", False)
+            else util.concurrency.await_only
+        )
+        listener = fn
+
+        def fn(*_args, **kwargs):
+            return await_(listener(*_args, **kwargs))
+
     _event_key(target, identifier, fn).listen(*args, **kw)
 
 
diff --git a/lib/sqlalchemy/util/concurrency.py b/lib/sqlalchemy/util/concurrency.py
@@ -9,6 +9,7 @@
         pass
     else:
         have_greenlet = True
+        from inspect import iscoroutinefunction
         from ._concurrency_py3k import await_only
         from ._concurrency_py3k import await_fallback
         from ._concurrency_py3k import greenlet_spawn
@@ -48,3 +49,6 @@ def _util_async_run(fn, *arg, **kw):  # noqa F81
 
     def _util_async_run_coroutine_function(fn, *arg, **kw):  # noqa F81
         _not_implemented()
+
+    def iscoroutinefunction(fn):
+        return False
