# Golang Configuration

> Standards for application configuration using environment variables and libraries. Use when managing Go application config with environment variables or viper. (triggers: configs/**, cmd/**, configuration, env var, viper, koanf)

- Skill: `comeonoliver/golang-configuration` (Agent Skill)
- Install (CLI): `npx skillmds@latest add comeonoliver/golang-configuration`
- Raw SKILL.md: https://api.skillmd.com/api/skills/comeonoliver/golang-configuration/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: ComeOnOliver (https://skillmd.com/u/comeonoliver)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/comeonoliver/golang-configuration

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# Golang Configuration Standards

## **Priority: P1 (STANDARD)**

## Principles

- **12-Factor App**: Store config in environment variables.
- **Typed Config**: Load config into a struct, validate it immediately.
- **Secrets**: Never commit secrets. Use env vars or secret managers.
- **No Globals**: Return a Config struct and inject it.

## Libraries

- **Standard Lib**: `os.Getenv` for simple apps.
- **Viper**: Industry standard for complex configs (supports env, config files, remote config).
- **Koanf**: Lighter, cleaner alternative to Viper.
- **Caarlos0/env**: Good for strict struct tagging.

## Pattern

1. Define `Config` struct.
2. Load from defaults.
3. Override from file (optional).
4. Override from Env (priority).
5. Validate.

## References

- [Config Pattern](references/config-patterns.md)


## Anti-Patterns

- **No hardcoded secrets**: Load all secrets from env vars or a secret manager.
- **No global config vars**: Return a typed Config struct and inject it via constructors.
- **No startup without validation**: Crash immediately on missing required env vars.