Heroku database showing password authentication failed after maintenance

Question

So i received a message from heroku saying it needs to carry out maintenance on my database and will be read only for a bit. However I go to check my site and the site isn't working for the pages that require data from the database, I go to check the logs and see this error message:

2022-05-20T09:57:55.246102+00:00 app[web.1]: sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) connection to server at "eu-west-1.compute.amazonaws.com" (52.18.116.67), port 5432 failed: FATAL:  password authentication failed for user "MYUSERNAME"
2022-05-20T09:57:55.246102+00:00 app[web.1]: connection to server at ".eu-west-1.compute.amazonaws.com" (52.18.116.67), port 5432 failed: FATAL:  no pg_hba.conf entry for host "IP", user "MYUSERNAME", database "DATABASE", no encryption

I haven't touched or changed anything, so not sure what the problem is.

Are you hard coding the database url in you app or getting it from environment variable? — ahmed, May 20 '22 at 10:31
@ahmed getting the url like this uri = os.environ.get('POSTGRES_URI_PROD') which gets the environment variable from heroku secret keys — sfhdfh23, May 20 '22 at 10:39
@ahmed ive always had it as that and its worked, inst database URL something different? — sfhdfh23, May 20 '22 at 10:43
Heroku can change the url, you can even change it from dashboard, that's why you have to use `DATABASE_URL` which heroku ensure it will always have a working url — ahmed, May 20 '22 at 10:44
@ahmed try this now i get another error sqlalchemy.exc.NoSuchModuleError: Can't load plugin: sqlalchemy.dialects:postgres — sfhdfh23, May 20 '22 at 10:46

score 1 · Accepted Answer · answered May 20 '22 at 10:51

This happen if you are not using the "dynamic" environment variable that Heroku manage for connecting to a PostgreSQL database

If you have just one, it's better to use DATABASE_URL as it always have up-to-date location and credentials

Heroku can change the url for various reasons, ex credentials rotation

If you are using sqlalchemy you might need a slight workaround:

os.environ.get('DATABASE_URL').replace('postgres://', 'postgresql://')

Heroku database showing password authentication failed after maintenance

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