Refactor app into eligibility_server/app

[machikoyasuda]

What this PR does

close #12

• Moves app.py into eligibility_server/app.py
• Fixes tests by changing app import to eligibility_server.app
• Uses new method to run Debugger in VS Code: https://code.visualstudio.com/docs/python/tutorial-flask#_run-the-app-in-the-debugger
• Removes debugpy dependency

Testing

Make sure you can:

• - docker compose build server docker compose up server - open http://localhost:XXXX/healthcheck
• - open in VSCode in remote container: enter command flask run -h 0.0.0.0 then open http://localhost:XXXX/healthcheck
• - open in VSCode in remote container: get debugger mode running with F5
• - open in VSCode in remote container: get debugger mode running with F5, change some server-side code, and the debugger should automatically restart
• - open in VSCode in remove container: run pytest

Docs

The new port can be found from the VS Code port panel, or with the docker command: docker ps

[machikoyasuda]

At the moment I'm running this PR's dev container locally with this change:

[machikoyasuda]

Tried:

docker-compose run --rm -e DEBUGGER=True -e FLASK_APP=eligibility_server/app.py -e FLASK_ENV=development --service-ports dev python -m debugpy --wait-for-client --listen 0.0.0.0:5678 eligibility_server/app.py

and added a breakpoint in

if __name__ == "__main__":
    print(app)
    print("STUFF")
    breakpoint()
    app.run(host="0.0.0.0", debug=True)  # nosec

I was able to get the VS Code debugger working and look into the app var, etc., but - once I clicked ▶️, the server broke.

➜  eligibility-server git:(chore/move-into-folder) ✗ docker-compose run --rm -e DEBUGGER=True -e FLASK_APP=eligibility_server/app.py -e FLASK_ENV=development --service-ports dev python -m debugpy --wait-for-client --listen 0.0.0.0:5678 eligibility_server/app.py
Creating eligibility-server_dev_run ... done
<Flask 'app'>
STUFF
 * Serving Flask app "app" (lazy loading)
 * Environment: development
 * Debug mode: on
 * Running on all addresses.
   WARNING: This is a development server. Do not use it in a production deployment.
 * Running on http://192.168.0.2:5000/ (Press CTRL+C to quit)
 * Restarting with stat
No module named app

[thekaveman]

So I just came across this: https://code.visualstudio.com/docs/python/tutorial-flask#_run-the-app-in-the-debugger

Which makes this whole thing much easier! I feel like this is new, debugpy is built in now!? 🤷

So two tricks that got this working for me:

.vscode/launch.json was slightly different from the above docs, but not by much:

{
  "name": "Flask: Eligibility Verification Server",
  "type": "python",
  "request": "launch",
  "module": "flask",
  "args": [
    "run",
    "--host",
    "0.0.0.0"
  ],
  "env": {
    "FLASK_DEBUG": "1",
    "FLASK_ENV": "development"
  }
}

This now starts the server on-demand with F5, and watch/reload is also active! Possible to start/stop/restart as well.

docker-compose.yml got much simpler:

dev:
  build:
    context: .
    dockerfile: Dockerfile.dev
  entrypoint: []
  command: sleep infinity
  image: eligibility_server:dev
  ports:
    - 5000
  volumes:
    - ./:/home/calitp/app/

command: sleep infinity ensures the devcontainer continues to run even if the server code crashes/dies, or when debug mode is stopped.

[thekaveman]

There's a similar write-up for Django, which I tried with benefits and... it worked!

https://code.visualstudio.com/docs/python/tutorial-django#_create-a-debugger-launch-profile

See cal-itp/benefits#126

[thekaveman]

Great job! Few small changes, added some links to more info about Docker entrypoint/command.

[thekaveman]

Forgot to add:

You can remove debugpy from the requirements.txt file too!

[thekaveman]

🚀 🎸