remove uvicorn boilerplate by implementing a uvicorn-hmr cli

Author: CNSeniorious000

examples/fastapi/main.py

@@ -12,35 +12,3 @@
 @app.get("/")
 def redirect_to_docs():
     return RedirectResponse("/docs")
-
-
-def start_server():
-    global stop
-
-    from atexit import register, unregister
-    from threading import Event, Thread
-
-    from uvicorn import Config, Server
-
-    if stop := globals().get("stop"):  # type: ignore
-        unregister(stop)
-        stop()  # type: ignore
-
-    server = Server(Config(app, host="localhost"))
-
-    finish = Event()
-
-    def run_server():
-        server.run()
-        finish.set()
-
-    Thread(target=run_server, daemon=True).start()
-
-    @register
-    def stop():
-        server.should_exit = True
-        finish.wait()
-
-
-if __name__ == "__main__":
-    start_server()

examples/fastapi/pyproject.toml

@@ -4,5 +4,8 @@ version = "0"
 requires-python = ">=3.12"
 dependencies = [
     "fastapi~=0.115.6",
-    "uvicorn~=0.34.0",
+    "uvicorn-hmr",
 ]
+
+[tool.uv.sources]
+uvicorn-hmr = { path = "../../packages/uvicorn-hmr" }

packages/uvicorn-hmr/pyproject.toml

@@ -0,0 +1,15 @@
+[project]
+name = "uvicorn-hmr"
+version = "0.0.1"
+dependencies = [
+    "hmr~=0.1.2",
+    "typer-slim~=0.15.1",
+    "uvicorn>=0.24.0",
+]
+
+[project.scripts]
+uvicorn-hmr = "uvicorn_hmr:app"
+
+[build-system]
+requires = ["pdm-backend"]
+build-backend = "pdm.backend"

packages/uvicorn-hmr/uvicorn_hmr.py

@@ -0,0 +1,74 @@
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+from typer import Argument, Typer
+
+app = Typer(help="Hot Module Replacement for Uvicorn", add_completion=False)
+
+
+@app.command(no_args_is_help=True)
+def main(slug: str = Argument("main:app"), reload_include: str = str(Path.cwd()), reload_exclude: str = ".venv"):
+    module, attr = slug.split(":")
+
+    fragment = Path(module.replace(".", "/"))
+
+    if (path := fragment.with_suffix(".py")).is_file() or (path := fragment / "__init__.py").is_file():
+        file = path.resolve()
+    else:
+        raise FileNotFoundError(f"Module `{module}` not found")
+
+    import sys
+    from atexit import register
+    from importlib import import_module
+    from threading import Event, Thread
+
+    from reactivity import memoized_method
+    from reactivity.hmr import SyncReloader
+    from uvicorn import Config, Server
+
+    if TYPE_CHECKING:
+        from uvicorn._types import ASGIApplication
+
+    cwd = str(Path.cwd())
+    if cwd not in sys.path:
+        sys.path.insert(0, cwd)
+
+    @register
+    def _():
+        stop_server()
+
+    def stop_server():
+        pass
+
+    def start_server(app: "ASGIApplication"):
+        nonlocal stop_server
+
+        server = Server(Config(app, host="localhost"))
+        finish = Event()
+
+        def run_server():
+            server.run()
+            finish.set()
+
+        Thread(target=run_server, daemon=True).start()
+
+        def stop_server():
+            server.should_exit = True
+            finish.wait()
+
+    class Reloader(SyncReloader):
+        def __init__(self):
+            super().__init__(str(file), {reload_include}, {reload_exclude})
+            self.error_filter.exclude_filenames.add(__file__)  # exclude error stacks within this file
+            self.module = import_module(module)
+
+        @memoized_method
+        def run_entry_file(self):
+            with self.error_filter:
+                self.module._ReactiveModule__load.invalidate()
+                self.module._ReactiveModule__load()
+
+                stop_server()
+                start_server(getattr(self.module, attr))
+
+    Reloader().keep_watching_until_interrupt()

pyproject.toml

@@ -3,10 +3,17 @@ name = "hmr-cookbook"
 version = "0"
 requires-python = ">=3.12"
 dependencies = [
-    "hmr>=0.1.1.1,<0.2",
+    "hmr~=0.1.2",
     "ruff~=0.9.0",
+    "uvicorn-hmr",
 ]
 
+[tool.uv.workspace]
+members = ["packages/*"]
+
+[tool.uv.sources]
+uvicorn-hmr = { workspace = true }
+
 [tool.pyright]
 typeCheckingMode = "standard"