How to run with Fastapi/Uvicorn

[ryanking8215]

a small hy script by Fastapi and uvicorn

(import fastapi [FastAPI])
(import uvicorn)
(require hyrule *)

(setv app (FastAPI))

((app.get "/")
  (fn :async []
    {"message" "Hello, world"}))


(defmain []
  (uvicorn.run "app:app" :host "0.0.0.0" :port 8300 :reload True))

When run it, got

$ .venv/bin/hy app.hy
INFO:     Will watch for changes in these directories: ['./lab/hy/web_demo']
INFO:     Uvicorn running on http://0.0.0.0:8300 (Press CTRL+C to quit)
INFO:     Started reloader process [54412] using StatReload
Traceback (most recent call last):
  File "./lab/hy/web_demo/.venv/bin/hy", line 8, in <module>
    sys.exit(hy_main())
             ~~~~~~~^^
  File "<string>", line 1, in <module>
NameError: name 'from' is not defined
Traceback (most recent call last):
  File "./lab/hy/web_demo/.venv/bin/hy", line 8, in <module>
    sys.exit(hy_main())
             ~~~~~~~^^
  File "<string>", line 1, in <module>
NameError: name 'from' is not defined

uvicorn runs failed, seems it can't recognize "app:app" I guess, I have no idea how to fix it since the python version is ok.

[Kodiologist]

I haven't used these libraries, but if they expect a Python script, try giving them a minimal Python script that imports your Hy code.

[ryanking8215]

"app:app" is not a separate Python script, it is the script itself. "app:app" is form of "module:attribute", what is the first parameter of uvicorn.run() as documented in "https://www.uvicorn.org/settings/".

The first "app" means the python module("app.py" here), the second "app" is the FastAPI instance created in "app.py".

python version

# file: app.py

app=FastAPI()

@app.get("/")
async def root():
    return {"message": "hello, world"}

if __name__=='__main__':
   uvicorn.run("app:app", host="0.0.0.0", port=8030, reload=True)

if the filename changes to "main.py", it would be uvicorn.run("main:app", ...).

The python version runs ok. But for hy version, it runs failed. Seems it can't recognize "app:app", there is no python module named "app"?