[agounaris]

In a cloud native world, code should not be aware of the environment. I don't see a reason to have multiple files per env and not just different configuration. This kinda of creates a mental model against true configurability.

The solution with multiple files actually goes against the 12fapp

"Sometimes apps batch config into named groups (often called “environments”) named after specific deploys, such as the development, test, and production environments in Rails. This method does not scale cleanly"

[whalesalad]

Nothing is black and white. There is a multi-dimensional scale that your application will land on. The dimensions might be static (yaml) versus dynamic (py) or all data stored outside the app (ENV vars only or similar, devout adherence to the 12 factor religion) versus storing config 100% in your app.

If you plotted those axis' on a four quadrant grid you'd be able to draw a little dot somewhere on it for your particular app. Your app is not my app. My apps are not always the same, either. My personal blog for instance has a far simpler configuration than the tools I build for my clients.

"In a cloud native world, code should not be aware of the environment."

This is a dogmatic fallacy. There are tons of reasons code should be aware of its environment. The problem is that most people are unable to agree on what "aware of its environment" actually means. I do not agree that my code should not know what the staging or production environment is. This is literal devops! Developing and building your application/system with the logistics of shipping it in mind.

When the dust has settled from configuration arguments the most important thing you can do when designing your application is to first replace the word "application" with the word "system" in your mind and begin to think about it as a system. The system contains subsystems: config, persistence, presentation, blob storage, logging, etc... and all of these are self-contained and isolated units that start and stop for their own unique reasons during the app/system lifecycle. If you design things to allow for this decoupling, the right approach for configuration will manifest itself.