Unable to access flask endpoints after dockerizing the app

Question

I'm working on a flask application which has a list of urls registered. I was able to run the flask app locally and access the urls which are registered for it.

But when I dockerize the app and running it using docker-compose, I'm not able to access the urls for the app.

When running the app locally, if I access the app.url_map of the app, I was able to see list of all registered urls for that app. (I created an endpoint - /urls which when hit returns url_map list)

But when I try to hit the same endpoint - /urls after running the app in docker, I don't see any list in that except the /urls endpoint which is basically itself.

Where am I going wrong?

Here's the wsgi.py file:

import os
from flask import Flask, jsonify
from app.workload.views import register_workload_urls

def load_urls(app):
    app_mode = os.getenv("APP_MODE")
    if app_mode == "WORKLOAD":
        register_workload_urls(app)

application = Flask(__name__)

@application.route('/urls')
def urls():
    return jsonify({"APP": str(os.getenv("APP_MODE")), "URLs registered": f"{str(application.url_map)}"})

if __name__ == "__main__":
    load_urls(application)
    application.run()

views.py:

def register_workload_urls(application):
    @application.route('/api/workload/health/check/')
    def w_check():
        return jsonify({'status': f"Workload service is {app.config_pub.status}."})

    @application.route('/api/workload/health/up/')
    def w_up():
        app.config_pub.status = "UP"
        app.config_pub.dispatch("UP")
        return jsonify({'status': f"Workload service is {app.config_pub.status}."})

    @application.route('/api/workload/health/down/')
    def w_down():
        app.config_pub.status = "DOWN"
        app.config_pub.dispatch("DOWN")
        return jsonify({'status': f"Workload service is {app.config_pub.status}."})

docker-compose.yml:

  workload_service:
    container_name: workload_container
    restart: always
    image: workload
    build: 
      context: ./dsdp
      dockerfile: Dockerfile.app.local
    ports:
      - "5000:5000"
    environment:
        - PYTHONPATH=.
        - FLASK_APP=wsgi.py
        - FLASK_DEBUG=1
        - CONFIG_PATH=config/local
        - APP_MODE=WORKLOAD
    command: flask run --host=0.0.0.0 --port 5000

Dockerfile.app.local:

FROM python:3.7
RUN mkdir -p /var/www/dsdp/
WORKDIR /var/www/dsdp/
COPY . /var/www/dsdp/
RUN pip3 install --no-cache-dir -r requirements.txt
EXPOSE 5000

Output of /urls when running in docker:

{
  "APP": "WORKLOAD",
  "URLs registered": "Map([<Rule '/urls' (GET, HEAD, OPTIONS) -> urls>,\n <Rule '/static/<filename>' (GET, HEAD, OPTIONS) -> static>])"
}

Answer 1

Looks like some issue with having the code in wsgi.py file. Removed app creation code from wsgi.py file and pasted in __init__.py file in app folder and imported the function from there.

Everything is working as expected now.