The Problem

The current order of precedence for resolving arguments is as follows:

1. CLI flags
2. Config file (if configured)
3. Env var (if configured)
4. Default values (if configured)

I wanted to start an active discussion around the possibility of swapping the order of precedence for config files and env vars (or less favorably, offering a way to configure the order of precedence):

1. CLI flags
2. Env var (if configured)
3. Config file (if configured)
4. Default values (if configured)

Why

Precedence... I believe there is already and standard and understood order of precedence in the community. I also believe consistency is paramount. When picking up a tool the less domain knowledge I need have to know the better.

Notable examples:

1. npm - The package manager for JavaScript
2. aws - A unified tool that provides a consistent interface for interacting with all parts of AW
3. docker - Docker is the world's leading software containerization platform
4. ansible - An IT automation tool
5. git - A distributed version control system designed to handle everything from small to very large projects with speed and efficiency.
6. viper - Viper is a complete configuration solution for go applications including 12 factor apps