GCS, Cloud Run Jobs, Error: '' is not a valid port number

Question

I have a Cloud Run service. It is a simple code made from python Flask. I normally trigger this task from my local PC, with CUrl command and it works without any problem. Today I wanted to do the same task with Cloud Run Jobs but, it fails.

The only log I can see is this:

2022-12-23 01:54:05.403 JST
Error: '' is not a valid port number.
2022-12-23 01:54:05.437 JST
Container called exit(1).
2022-12-23 01:54:07.355 JST
Cloud Runtaskfoobar-1234 {foobar}

These are places in my code where port is used(/cofigured)

Dockerfile

...

CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 --timeout 0 main:app

main.py

...

if __name__ == "__main__":
    app.run(debug=True, host="0.0.0.0", port=int(os.environ.get("PORT", 8080)))

Things I tried:

When creating a Cloud Run job, under "VARIABLES & SECRETS", you can add environment variables. I tried to manually add "PORT" but it says "This name is reserved.".

Answer 1

A Job shouldn't listen on a port. It should run as soon as the container is started and terminate when the job is done. That's the difference between Services and Jobs.