Add async_engine_from_config()

Added :func:`_asyncio.async_engine_config` function to create
an async engine from a configuration dict.  This otherwise
behaves the same as :func:`_sa.engine_from_config`.

Fixes: #7301
Closes: #7302
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/7302
Pull-request-sha: c7c758833b6c37b7509b8c5bed4f26ac0ccc0395

Change-Id: I64feadf95b5015c24fe0fa0dbae6755b72d1713e

2 files changed, 24 insertions, 0 deletions

diff --git a/lib/sqlalchemy/ext/asyncio/__init__.py b/lib/sqlalchemy/ext/asyncio/__init__.py
index ac3b905c6..031039713 100644
--- a/lib/sqlalchemy/ext/asyncio/__init__.py
+++ b/lib/sqlalchemy/ext/asyncio/__init__.py
@@ -5,6 +5,7 @@
 # This module is part of SQLAlchemy and is released under
 # the MIT License: https://www.opensource.org/licenses/mit-license.php
 
+from .engine import async_engine_from_config
 from .engine import AsyncConnection
 from .engine import AsyncEngine
 from .engine import AsyncTransaction
diff --git a/lib/sqlalchemy/ext/asyncio/engine.py b/lib/sqlalchemy/ext/asyncio/engine.py
index 67d944b9c..476d5515c 100644
--- a/lib/sqlalchemy/ext/asyncio/engine.py
+++ b/lib/sqlalchemy/ext/asyncio/engine.py
@@ -42,6 +42,29 @@ def create_async_engine(*arg, **kw):
     return AsyncEngine(sync_engine)
 
 
+def async_engine_from_config(configuration, prefix="sqlalchemy.", **kwargs):
+    """Create a new AsyncEngine instance using a configuration dictionary.
+
+    This function is analogous to the :func:`_sa.engine_from_config` function
+    in SQLAlchemy Core, except that the requested dialect must be an
+    asyncio-compatible dialect such as :ref:`dialect-postgresql-asyncpg`.
+    The argument signature of the function is identical to that
+    of :func:`_sa.engine_from_config`.
+
+    .. versionadded:: 1.4.29
+
+    """
+    options = {
+        key[len(prefix) :]: value
+        for key, value in configuration.items()
+        if key.startswith(prefix)
+    }
+    options["_coerce_config"] = True
+    options.update(kwargs)
+    url = options.pop("url")
+    return create_async_engine(url, **options)
+
+
 class AsyncConnectable:
     __slots__ = "_slots_dispatch", "__weakref__"