Heroku: python app works locally but does't on remote after git push

Question

I'm trying to deploy a python app that supports redis and I'm currently facing a problem. I have two git branches, one for production and one for dev and two different heroku apps (python-app, dev-python-app). My git repos are:

git remote
heroku
heroku-test

I use the fallowing commands to deploy the heroku-test to check if the app works correctly before passing to prod:

git branch dev-python-app
git add .
git commit -m "commit msg"
git push heroku-test dev-python-app:master

It says that everything's ok: "remote: Verifying deploy... done." but the app won't start. If I check logs with: heroku logs --tail -a dev-python-app:

2022-02-09T10:36:29.000000+00:00 app[api]: Build started by user *****
2022-02-09T10:36:53.638128+00:00 app[api]: Deploy 267f3889 by user ****
2022-02-09T10:36:53.638128+00:00 app[api]: Release v21 created by user ****
2022-02-09T10:37:02.000000+00:00 app[api]: Build succeeded

The stange thing is that if I run a one-off dyno using heroku run bash -a dev-python-app and than start the python app as: python3 main.py it works perfectly.

Moreover, It'd be useful to know that I tried this mentioned steps before introducing redis support to the app and It worked perfectly so could be redis the problem?

What do you think? Thank you

Answer 1

I fixed that. The problem was to scale the working process:

heroku ps:scale worker=1 -a dev-python-app