Feature/async

.github/workflows/ci.yml

@@ -6,15 +6,18 @@ on:
   push:
     branches:
     - master
-    
+
 jobs:
   test:
     name: test
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        build: [linux_3.8, windows_3.8, mac_3.8, linux_3.7]
+        build: [linux_3.9, linux_3.8, windows_3.8, mac_3.8]
         include:
+        - build: linux_3.9
+          os: ubuntu-latest
+          python: 3.9
         - build: linux_3.8
           os: ubuntu-latest
           python: 3.8
@@ -24,9 +27,6 @@ jobs:
         - build: mac_3.8
           os: macos-latest
           python: 3.8
-        - build: linux_3.7
-          os: ubuntu-latest
-          python: 3.7
     steps:
     - name: Checkout repository
       uses: actions/checkout@v2
@@ -35,39 +35,39 @@ jobs:
       uses: actions/setup-python@v1
       with:
         python-version: ${{ matrix.python }}
-    
+
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip wheel
         pip install -r requirements.txt
-    
+
     # test all the builds apart from linux_3.8...
     - name: Test with pytest
       if: matrix.build != 'linux_3.8'
       run: pytest
-    
+
     # only do the test coverage for linux_3.8
     - name: Produce coverage report
       if: matrix.build == 'linux_3.8'
       run: pytest --cov=fastapi_sqlalchemy --cov-report=xml
-    
+
     - name: Upload coverage report
       if: matrix.build == 'linux_3.8'
       uses: codecov/codecov-action@v1
       with:
         file: ./coverage.xml
-  
+
   lint:
     name: lint
     runs-on: ubuntu-latest
     steps:
     - name: Checkout repository
       uses: actions/checkout@v2
-    
+
     - name: Set up Python
       uses: actions/setup-python@v1
       with:
-        python-version: 3.7
+        python-version: 3.8
 
     - name: Install dependencies
       run: pip install flake8
@@ -85,13 +85,13 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v1
       with:
-        python-version: 3.7
-    
+        python-version: 3.8
+
     - name: Install dependencies
-      # isort needs all of the packages to be installed so it can 
+      # isort needs all of the packages to be installed so it can
       # tell which are third party and which are first party
       run: pip install -r requirements.txt
-    
+
     - name: Check formatting of imports
       run: isort --check-only --diff --verbose
 

.github/workflows/release.yml

@@ -11,18 +11,18 @@ jobs:
     steps:
     - name: Checkout repository
       uses: actions/checkout@v2
-    
-    - name: Set up Python 3.7
+
+    - name: Set up Python 3.8
       uses: actions/setup-python@v1
       with:
-        python-version: 3.7
+        python-version: 3.8
 
     - name: Install the dependencies
       run: pip install --upgrade pip wheel setuptools
-    
+
     - name: Build the distributions
       run: python setup.py sdist bdist_wheel
-    
+
     - name: Upload to PyPI
       uses: pypa/gh-action-pypi-publish@master
       with:
@@ -36,10 +36,10 @@ jobs:
     steps:
     - name: Checkout repository
       uses: actions/checkout@v2
-    
+
     - name: Get the version
       run: echo ::set-env name=VERSION::${GITHUB_REF#refs/tags/}
-    
+
     - name: Create release
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

README.rst

@@ -40,7 +40,7 @@ Usage inside of a route
 
     app.add_middleware(DBSessionMiddleware, db_url="sqlite://")
 
-    # once the middleware is applied, any route can then access the database session 
+    # once the middleware is applied, any route can then access the database session
     # from the global ``db``
 
     @app.get("/users")
@@ -49,7 +49,7 @@ Usage inside of a route
 
         return users
 
-Note that the session object provided by ``db.session`` is based on the Python3.7+ ``ContextVar``. This means that
+Note that the session object provided by ``db.session`` is based on the Python3.8+ ``ContextVar``. This means that
 each session is linked to the individual request context in which it was created.
 
 Usage outside of a route
@@ -82,15 +82,15 @@ Sometimes it is useful to be able to access the database outside the context of
         """Count the number of users in the database and save it into the user_counts table."""
 
         # we are outside of a request context, therefore we cannot rely on ``DBSessionMiddleware``
-        # to create a database session for us. Instead, we can use the same ``db`` object and 
+        # to create a database session for us. Instead, we can use the same ``db`` object and
         # use it as a context manager, like so:
 
         with db():
             user_count = db.session.query(User).count()
 
             db.session.add(UserCount(user_count))
             db.session.commit()
-        
+
         # no longer able to access a database session once the db() context manager has ended
 
         return users

fastapi_sqlalchemy/__init__.py

@@ -1,5 +1,6 @@
 from fastapi_sqlalchemy.middleware import DBSessionMiddleware, db
+from fastapi_sqlalchemy.async_middleware import AsyncDBSessionMiddleware, async_db
 
-__all__ = ["db", "DBSessionMiddleware"]
+__all__ = ["db", "DBSessionMiddleware", "async_db", "AsyncDBSessionMiddleware"]
 
-__version__ = "0.2.1"
+__version__ = "0.3.0"

fastapi_sqlalchemy/async_middleware.py

@@ -0,0 +1,89 @@
+from contextvars import ContextVar
+from typing import Dict, Optional, Union
+
+from sqlalchemy.engine.url import URL
+from sqlalchemy.ext.asyncio import AsyncEngine, AsyncSession, create_async_engine
+from sqlalchemy.orm import sessionmaker
+from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
+from starlette.requests import Request
+from starlette.types import ASGIApp
+
+from fastapi_sqlalchemy.exceptions import (
+    MissingSessionError, SessionNotInitialisedError
+)
+
+_Session: sessionmaker = None
+_session: ContextVar[Optional[AsyncSession]] = ContextVar("_session", default=None)
+
+
+class AsyncDBSessionMiddleware(BaseHTTPMiddleware):
+    def __init__(
+        self,
+        app: ASGIApp,
+        db_url: Optional[Union[str, URL]] = None,
+        custom_engine: Optional[AsyncEngine] = None,
+        engine_args: Dict = None,
+        session_args: Dict = None,
+        commit_on_exit: bool = False,
+    ):
+        super().__init__(app)
+        global _Session
+        engine_args = engine_args or {}
+        self.commit_on_exit = commit_on_exit
+
+        session_args = session_args or {}
+        if not custom_engine and not db_url:
+            raise ValueError("You need to pass a db_url or a custom_engine parameter.")
+        if not custom_engine:
+            engine = create_async_engine(db_url, future=True, **engine_args)
+        else:
+            engine = custom_engine
+        _Session = sessionmaker(bind=engine, class_=AsyncSession, **session_args)
+
+    async def dispatch(self, request: Request, call_next: RequestResponseEndpoint):
+        async with async_db(commit_on_exit=self.commit_on_exit):
+            response = await call_next(request)
+        return response
+
+
+class AsyncDBSessionMeta(type):
+    # using this metaclass means that we can access db.session as a property at a class level,
+    # rather than db().session
+    @property
+    def session(self) -> AsyncSession:
+        """Return an instance of Session local to the current async context."""
+        if _Session is None:
+            raise SessionNotInitialisedError
+
+        session = _session.get()
+        if session is None:
+            raise MissingSessionError
+
+        return session
+
+
+class AsyncDBSession(metaclass=AsyncDBSessionMeta):
+    def __init__(self, session_args: Dict = None, commit_on_exit: bool = False):
+        self.token = None
+        self.session_args = session_args or {}
+        self.commit_on_exit = commit_on_exit
+
+    async def __aenter__(self):
+        if not isinstance(_Session, sessionmaker):
+            raise SessionNotInitialisedError
+        self.token = _session.set(_Session(**self.session_args))
+        return type(self)
+
+    async def __aexit__(self, exc_type, exc_value, traceback):
+        sess = _session.get()
+        if exc_type is not None:
+            await sess.rollback()
+
+        if self.commit_on_exit:
+            await sess.commit()
+
+        await sess.close()
+        _session.reset(self.token)
+
+
+async_db: AsyncDBSessionMeta = AsyncDBSession

requirements.txt

@@ -1,37 +1,47 @@
-appdirs==1.4.3
-atomicwrites==1.3.0
-attrs==19.3.0
-black==19.10b0
-certifi==2019.9.11
-chardet==3.0.4
-click==7.1.1
-coverage==4.5.4
-entrypoints==0.3
-fastapi==0.52.0
-flake8==3.7.9
-idna==2.8
-importlib-metadata==1.5.0
-isort==4.3.21
+aiosqlite==0.17.0
+anyio==3.5.0
+async-generator==1.10
+atomicwrites==1.4.0
+attrs==21.4.0
+black==22.3.0
+certifi==2021.10.8
+cffi==1.15.0
+charset-normalizer==2.0.12
+click==8.1.3
+colorama==0.4.4
+coverage==6.3.2
+fastapi==0.77.1
+flake8==4.0.1
+greenlet==1.1.2
+h11==0.12.0
+httpcore==0.14.7
+httpx==0.22.0
+idna==3.3
+iniconfig==1.1.1
+isort==5.10.1
 mccabe==0.6.1
-more-itertools==7.2.0
-packaging==19.2
-pathspec==0.7.0
-pluggy==0.13.0
-py==1.8.0
-pycodestyle==2.5.0
-pydantic==0.32.2
-pyflakes==2.1.1
-pyparsing==2.4.2
-pytest==5.2.2
-pytest-cov==2.8.1
-PyYAML==5.3.1
-regex==2020.2.20
-requests==2.22.0
-six==1.12.0
-SQLAlchemy==1.3.10
-starlette==0.13.2
-toml==0.10.0
-typed-ast==1.4.1
-urllib3==1.25.6
+mypy-extensions==0.4.3
+outcome==1.1.0
+packaging==21.3
+pathspec==0.9.0
+platformdirs==2.5.2
+pluggy==1.0.0
+py==1.11.0
+pycodestyle==2.8.0
+pycparser==2.21
+pydantic==1.9.0
+pyflakes==2.4.0
+pyparsing==3.0.9
+pytest==7.1.2
+pytest-cov==3.0.0
+requests==2.27.1
+rfc3986==1.5.0
+sniffio==1.2.0
+sortedcontainers==2.4.0
+SQLAlchemy==1.4.36
+starlette==0.19.1
+tomli==2.0.1
+trio==0.20.0
+typing_extensions==4.2.0
+urllib3==1.26.9
 wcwidth==0.1.7
-zipp==3.1.0

setup.py

@@ -25,7 +25,7 @@
     packages=["fastapi_sqlalchemy"],
     package_data={"fastapi_sqlalchemy": ["py.typed"]},
     zip_safe=False,
-    python_requires=">=3.7",
+    python_requires=">=3.8",
     install_requires=["starlette>=0.12.9", "SQLAlchemy>=1.2"],
     classifiers=[
         "Development Status :: 4 - Beta",
@@ -34,9 +34,8 @@
         "Intended Audience :: Developers",
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3 :: Only",
         "Programming Language :: Python :: Implementation :: CPython",
         "Topic :: Internet :: WWW/HTTP :: HTTP Servers",