Add support for Docker secrets

[suhaskarnik]

Currently, the package hardcodes the DSN in Docker Compose. The DSN includes the user, password and DB name. As this is sensitive information, I propose that we allow passing these values as separate env vars and as files. This is similar to the approach taken by the standard Postgres image, which allows POSTGRES_USER, POSTGRES_PASSWORD and POSTGRES_DB, each of which also has a _FILE variant.

I've written the code for this, and have pushed the code to my own fork of this repo. The branch is here. Tests are running fine, and it's linted as well.

Please let me know your thoughts

[duaraghav8]

Thanks @suhaskarnik

I need to research a bit more on this since I wasn't familiar with it already. My initial thoughts:

• Agreed, supplying hard-coded DSN is not a good approach and we should allow the postgres way of supplying credentials.
• Since mcpjungle also supports sqlite as the lighter alternative to psql, the start command also needs to check the DB being used. If db is postgres, only then should this logic kick in.

I saw you branch, do you mind opening a PR here?
Once I've done more research on this, I'll help make any additional changes required and merge it.

[suhaskarnik]

This logic does indeed kick in only if the DB is Postgres.

In the original code, it uses Postgres if the DSN is populated, otherwise it picks sqlite. In the new branch, it checks for the presense of the POSTGRES_USER etc and if so, it uses those to construct the DSN. If those vars/secrets aren't available, the DSN doesn't get created, so the sqlite fallback will continue.

I have now created the PR

[duaraghav8]

Thank you! 👀