golang-spf13-viper

What problem does it solve?

It prevents broken or surprising configuration behavior in Go services by making spf13/viper’s precedence rules predictable and correctly wired (flags, env vars, files, defaults, and optional remote KV).

Core Features & Use Cases

• Layered precedence that behaves correctly: Ensures explicit Set and bound flags win over env vars and config files, and that defaults only apply when nothing else provides a value.
• Correct env var mapping for nested keys: Makes nested viper keys resolve from environment variables by using SetEnvPrefix, SetEnvKeyReplacer, and AutomaticEnv together.
• Production-safe struct decoding and testing patterns: Uses mapstructure tags, supports hot reload with validation, and avoids test pollution by using viper.New() per test.
• Unmarshal reliability for tricky types: Handles duration and weak/typed decoding issues via decode hooks and DecoderConfig options.

Quick Start

Ask your AI coding agent to wire spf13/viper in your Go app so that nested keys (like database.host) resolve from env vars using prefix + key replacer, flags are bound before command execution, missing config files are handled gracefully, and unmarshalling uses mapstructure tags with proper decode hooks.