go-viper

Use this skill to produce a clean Viper setup that reads configuration from file, flags, and environment with Viper's normal precedence:

1. explicit Set
2. flags
3. environment variables
4. config file
5. remote key/value store
6. defaults

Core approach

• Prefer viper.New() over the package global; build one configured instance and pass it where needed.
• Define a typed Config struct and unmarshal into it after all defaults, file paths, env bindings, and flag bindings are configured.
• Keep configuration bootstrap in one place such as internal/config or pkg/config with a Load(...) function.
• Treat the config file as optional only when the app design allows it; otherwise return a clear error.
• Bind flags and env explicitly for important keys, and use AutomaticEnv() plus an env key replacer for the general case.

Clean Viper bootstrap