Cloud Run Deploy fails: Container failed to start. Failed to start and then listen on the port defined by the PORT environment variable

I have a project which I had previously successfully deployed to Google Cloud Run, and set up with a trigger such that upon pushing to the repo's main branch on Github, it would automatically deploy. It worked great.

Then I tried to rename the github repo, which meant deleting and creating a new trigger, and now I cannot get it working again.

Everytime, the build succeeds but deployment fails with this error in Cloud Build:

Step #2 - "Deploy": ERROR: (gcloud.run.services.update) Cloud Run error: Container failed to start. Failed to start and then listen on the port defined by the PORT environment variable. Logs for this revision might contain more information.

I have not changed anything other than the repo name, leading me to believe the fix is not with my code, but I tried some changes there anyway.

I have looked into the solutions set forth in this post. However, I believe I am listening on the correct port.

My app is using Python and Flask, and contains this:

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

Which should use the ENV var Port (8080) and otherwise default to 8080. I also tried just using port=8080.

I tried explicitly exposing the port in the Dockerfile, which also did not work:

FROM python:3.7
   
#Copy files into docker image dir, and make that the current working dir
COPY . /docker-image
WORKDIR /docker-image

RUN pip install -r requirements.txt

CMD ["flask", "run", "--host", "0.0.0.0"]

EXPOSE 8080

Cloud Run does seem to be using port 8080 - if I dig into the response, I see this nested under Response.spec.container.0 :

ports: [
  0: {
    containerPort: 8080
    name: "http1"
  }
]

All that said, if I look at the logs, it shows "Now running on Port 5000".

I have no idea where that Port 5000 is coming from or being set, but trying to change the ports in Python/Flask and the Dockerfile to 5000 leads to the same errors.

How do I get it to run on Port 8080? It's very strange to me that this was working FINE prior to renaming the repo and creating a new trigger. How is this setup different? The Trigger does not give an option to set the port so I'm not sure how that caused this error.