Support ASGI servers for FastAPI (#2)

* Add support for ASGI applications

* Update readme

* Bump version

* Linting

README.md

@@ -5,7 +5,7 @@
 [![PyPI](https://img.shields.io/pypi/v/server-thread.svg?logo=python&logoColor=white)](https://pypi.org/project/server-thread/)
 [![conda](https://img.shields.io/conda/vn/conda-forge/server-thread.svg?logo=conda-forge&logoColor=white)](https://anaconda.org/conda-forge/server-thread)
 
-Launch a WSGIApplication in a background thread with werkzeug.
+Launch a WSGI or ASGI Application in a background thread with werkzeug or uvicorn.
 
 This application was created for [`localtileserver`](https://github.com/banesullivan/localtileserver)
 and provides the basis for how it can launch an image tile server as a
@@ -17,9 +17,9 @@ Python packages I have created that require a background service.
 
 ## 🚀 Usage
 
-Use the `ServerThread` with any WSGIApplication.
+Use the `ServerThread` with any WSGI or ASGI Application.
 
-Start by creating a WSGIApplication (this can be a flask app or a simple app
+Start by creating a application (this can be a flask app or a simple app
 like below):
 
 
@@ -80,3 +80,43 @@ If filing a bug report, please share a scooby `Report`:
 import server_thread
 print(server_thread.Report())
 ```
+
+
+## 🚀 Examples
+
+Minimal examples for using `server-thread` with common micro-frameworks.
+
+
+### 💨 FastAPI
+
+```py
+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/")
+def root():
+    return {"message": "Howdy!"}
+
+
+server = ServerThread(app)
+requests.get(f"http://{server.host}:{server.port}/").json()
+```
+
+### ⚗️ Flask
+
+```py
+from flask import Flask
+
+app = Flask("testapp")
+
+
+@app.route("/")
+def howdy():
+    return {"message": "Howdy!"}
+
+
+server = ServerThread(app)
+requests.get(f"http://{server.host}:{server.port}/").json()
+```

requirements.txt

@@ -3,3 +3,5 @@ requests
 scooby
 pytest
 pytest-cov
+fastapi
+uvicorn

server_thread/server.py

@@ -1,13 +1,24 @@
 import logging
 import os
 import threading
+import time
 from typing import Union
 
+import uvicorn
 from werkzeug.serving import make_server
 
 logger = logging.getLogger(__name__)
 
 
+def is_fastapi(app):
+    try:
+        from fastapi import FastAPI
+
+        return isinstance(app, FastAPI)
+    except ImportError:  # pragma: no cover
+        pass
+
+
 class ServerDownError(Exception):
     """Raised when a ServerThread is down."""
 
@@ -61,16 +72,108 @@ def shutdown_server(key: int, force: bool = False):
             logger.error(f"Server for key ({key}) not found.")
 
 
+class ServerBase:
+    def __init__(self, app, host, port, debug: bool = False):
+        raise NotImplementedError  # pragma: no cover
+
+    def shutdown(self):
+        raise NotImplementedError  # pragma: no cover
+
+    def __del__(self):
+        self.shutdown()
+
+    @property
+    def port(self):
+        raise NotImplementedError  # pragma: no cover
+
+    @property
+    def host(self):
+        raise NotImplementedError  # pragma: no cover
+
+    @property
+    def serve_forever(self):
+        raise NotImplementedError  # pragma: no cover
+
+
+class WSGIServer(ServerBase):
+    """Manager for WSGI applications."""
+
+    def __init__(self, app, host, port, debug: bool = False):
+        self.server = make_server(host, port, app, threaded=True, passthrough_errors=debug)
+
+    def shutdown(self):
+        self.server.shutdown()
+        self.server.server_close()
+
+    @property
+    def port(self):
+        return self.server.port
+
+    @property
+    def host(self):
+        return self.server.host
+
+    @property
+    def serve_forever(self):
+        return self.server.serve_forever
+
+
+class ASGIServer(ServerBase):
+    """Manager for ASGI applications."""
+
+    def __init__(self, app, host, port, debug: bool = False):
+        config = uvicorn.Config(
+            app, host=host, port=port, log_level="debug" if debug else "critical"
+        )
+        self.server = uvicorn.Server(config)
+
+    @property
+    def sock(self):
+        if self.server.started:
+            if (
+                hasattr(self.server, "servers")
+                and len(self.server.servers)  # noqa: W503
+                and len(self.server.servers[0].sockets)  # noqa: W503
+            ):
+                return self.server.servers[0].sockets[0]
+            else:
+                raise ServerDownError("Server started, but no servers present")
+        else:
+            timeout = time.time() + 10
+            while not self.server.started:
+                if time.time() > timeout:
+                    raise ServerDownError("Server not started")
+        return self.sock
+
+    def shutdown(self):
+        self.server.should_exit = True
+        self.server.handle_exit(0, None)
+        # await self.server.shutdown()
+
+    @property
+    def port(self):
+        return self.sock.getsockname()[1]
+
+    @property
+    def host(self):
+        return self.sock.getsockname()[0]
+
+    @property
+    def serve_forever(self):
+        return self.server.run
+
+
 class ServerThread(threading.Thread):
     """Launch a server as a background thread."""
 
     def __init__(
         self,
-        app,  # WSGIApplication
+        app,  # WSGI or ASGI Application
         port: int = 0,
         debug: bool = False,
         start: bool = True,
         host: str = "127.0.0.1",
+        wsgi: bool = None,
     ):
         self._lts_initialized = False
         if not isinstance(port, int):
@@ -86,7 +189,11 @@ def __init__(
 
         if os.name == "nt" and host == "127.0.0.1":
             host = "localhost"
-        self.srv = make_server(host, port, app, threaded=True)
+
+        if (wsgi is not None and not wsgi) or (wsgi is None and is_fastapi(app)):
+            self.srv = ASGIServer(app, host, port, debug=debug)
+        else:  # Fallback to WSGI
+            self.srv = WSGIServer(app, host, port, debug=debug)
 
         if hasattr(app, "app_context"):
             self.ctx = app.app_context()
@@ -104,7 +211,6 @@ def __init__(
     def shutdown(self):
         if self._lts_initialized and self.is_alive():
             self.srv.shutdown()
-            self.srv.server_close()
             self.join()
 
     def __del__(self):

setup.py

@@ -13,14 +13,14 @@
     long_description = ""
 
 # major, minor, patch
-version_info = 0, 1, 0
+version_info = 0, 2, 0
 # Nice string for the version
 __version__ = ".".join(map(str, version_info))
 
 setup(
     name="server-thread",
     version=__version__,
-    description="Launch a WSGIApplication in a background thread with werkzeug.",
+    description="Launch a WSGI or ASGI Application in a background thread with werkzeug or uvicorn.",
     long_description=long_description,
     long_description_content_type="text/markdown",
     author="Bane Sullivan",
@@ -39,6 +39,7 @@
     python_requires=">=3.7",
     install_requires=[
         "scooby",
+        "uvicorn",
         "werkzeug",
     ],
 )

tests/conftest.py

@@ -1,3 +1,4 @@
+from fastapi import FastAPI
 from flask import Flask
 import pytest
 
@@ -11,3 +12,14 @@ def howdy():
         return "howdy!"
 
     return app
+
+
+@pytest.fixture
+def fastapi_app():
+    app = FastAPI()
+
+    @app.get("/")
+    def root():
+        return {"message": "Howdy!"}
+
+    return app

tests/test_server.py

@@ -7,6 +7,18 @@
 def test_basic_flask_app(flask_app):
     server = ServerThread(flask_app, debug=True)
     requests.get(f"http://{server.host}:{server.port}/").raise_for_status()
+    server = ServerThread(flask_app, debug=True, wsgi=True)
+    requests.get(f"http://{server.host}:{server.port}/").raise_for_status()
+
+
+def test_basic_fastapi_app(fastapi_app):
+    server = ServerThread(fastapi_app, debug=True, wsgi=False)
+    requests.get(f"http://{server.host}:{server.port}/").raise_for_status()
+
+
+def test_fastapi_app_auto_detect(fastapi_app):
+    server = ServerThread(fastapi_app, debug=True)
+    requests.get(f"http://{server.host}:{server.port}/").raise_for_status()
 
 
 def test_bad_port(flask_app):
@@ -22,3 +34,13 @@ def test_server_shutdown(flask_app):
     del server
     with pytest.raises(requests.ConnectionError):
         requests.get(url).raise_for_status()
+
+
+def test_server_shutdown_fastapi(fastapi_app):
+    server = ServerThread(fastapi_app, debug=True)
+    url = f"http://{server.host}:{server.port}/"
+    requests.get(url).raise_for_status()
+    server.shutdown()
+    del server
+    with pytest.raises(requests.ConnectionError):
+        requests.get(url).raise_for_status()