Heroku request timeout error code = H12

[bhu800]

While deploying the application to Heroku the app is facing

Error log from Heroku:

at=error code=H12 desc="Request timeout" method=GET path="/socket.io/?EIO=3&transport=polling&t=NGISqUR&sid=a9a4214a17454ab288ef6bd429b4721d" host=gcsbot-iitmandi.herokuapp.com request_id=dfcea01a-3829-4c05-aecc-70d4f91f97e2 fwd="157.47.140.61" dyno=web.1 connect=0ms service=30001ms status=503 bytes=0 protocol=https

This might be caused due to:
1.) Heroku app is not able to access google-sheet API (try to remove google-sheet API feature and deploy and then check if it is the case) and it needs to set environment variables for google-api-credentials in Heroku API (like the secret key of flask app and Postgresql database have been configured.
2.) Since google-sheet-api takes a little more time first time (due to setting connection with google-sheet) (you can check this one time delay in your local machine too), so it might cause the timeout. (again removing google-sheet feature and then properly deploying it will confirm the possibility)
3.) Keras predictions or first-time database loading might take time.

background/solution of this error:
https://devcenter.heroku.com/articles/error-codes#h12-request-timeout
https://devcenter.heroku.com/articles/request-timeout
https://devcenter.heroku.com/articles/background-jobs-queueing
https://devcenter.heroku.com/articles/python-rq