Details:

• Environment: I’m using a Python 3.12-slim Docker image.

• Application: Django backend served with Uvicorn.

• Deployment: The app builds successfully, and migrations run without issues. However, when accessing the app, it returns a 502 error.

• Port Configuration: The PORT variable doesn’t seem to be correctly interpreted within the Docker container. The error logs show that "$PORT" is not being recognized as a valid integer, causing Uvicorn to fail to start.

Steps Taken:

1. Dockerfile Configuration:

   • I used the recommended Railway Dockerfile setup with Uvicorn, ensuring all necessary dependencies are installed (libpq-dev, gcc, libmariadb-dev, etc.).

   • I’ve tried both setting the PORT directly and using it as an environment variable, but Uvicorn still fails to recognize it.

The app runs but throws a 502 error when accessed, likely due to the incorrect handling of the PORT variable. I need help identifying why the PORT variable isn’t being correctly recognized and ensuring the app runs on the expected port.

Dockerfile:
FROM python:3.12-slim
WORKDIR /app
RUN apt-get update && apt-get install -y \ libpq-dev \ gcc \ libmariadb-dev-compat \ libmariadb-dev \ pkg-config \ && apt-get clean
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
CMD uvicorn main:app --host 0.0.0.0 --port $PORT

Url: https://eucerinv2backend-production.up.railway.app/