caddyserver/caddy · error

decoding config: %v

Error message

decoding config: %v

What it means

Error "decoding config: %v" thrown in caddyserver/caddy.

Source

Thrown at cmd/commandfuncs.go:632

	fmt.Println(string(adaptedConfig))

	// print warnings to stderr
	for _, warn := range warnings {
		msg := warn.Message
		if warn.Directive != "" {
			msg = fmt.Sprintf("%s: %s", warn.Directive, warn.Message)
		}
		caddy.Log().Named(adapterFlag).Warn(msg,
			zap.String("file", warn.File),
			zap.Int("line", warn.Line))
	}

	// validate output if requested
	if validateFlag {
		var cfg *caddy.Config
		err = caddy.StrictUnmarshalJSON(adaptedConfig, &cfg)
		if err != nil {
			return caddy.ExitCodeFailedStartup, fmt.Errorf("decoding config: %v", err)
		}
		err = caddy.Validate(cfg)
		if err != nil {
			return caddy.ExitCodeFailedStartup, fmt.Errorf("validation: %v", err)
		}
	}

	return caddy.ExitCodeSuccess, nil
}

func cmdValidateConfig(fl Flags) (int, error) {
	configFlag := fl.String("config")
	adapterFlag := fl.String("adapter")

	// load all additional envs as soon as possible
	err := handleEnvFileFlag(fl)
	if err != nil {
		return caddy.ExitCodeFailedStartup, err

View on GitHub (pinned to 50e54ee279)

Solutions

1. Ensure the adapted output is valid JSON; run 'caddy adapt' first and inspect its output for syntax errors.

When it happens

Trigger: Thrown at cmd/commandfuncs.go:632 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of caddyserver/caddy@50e54ee279 (2026-08-15). Data as JSON: /api/errors/008061fc2b37e571. Report an issue: GitHub.