Function SetContextTemplate

log/context.go:96–124

SetContextTemplate configures contextual fields rendered by WithContext for Fiber's default logger. Pass an empty ContextConfig (or ContextConfig{Format: DefaultFormat}) to disable contextual fields. It returns an error if config.Format cannot be parsed or if config.CustomTags attempts to override t

(config ContextConfig)

// It returns an error if config.Format cannot be parsed or if config.CustomTags attempts to
// override the reserved TagContextValue tag.
func SetContextTemplate(config ContextConfig) error {
	if _, ok := config.CustomTags[TagContextValue]; ok {
		return ErrContextTagReserved
	}

	contextMu.Lock()
	defer contextMu.Unlock()

	// Cloning the live tag map preserves prior RegisterContextTag entries —
	// callers that interleave RegisterContextTag with SetContextTemplate
	// expect the registration to remain visible. CustomTags layer on top.
	tags := maps.Clone(contextTags)
	maps.Copy(tags, config.CustomTags)
	tags[TagContextValue] = defaultContextValueTag

	var tmpl *logtemplate.Template[any, ContextData]
	if config.Format != "" {
		var err error
		tmpl, err = logtemplate.Build[any, ContextData](config.Format, tags)
		if err != nil {
			return err
		}
	}

	contextFormat = config.Format
	contextTags = tags
	contextTemplate.Store(tmpl)
	return nil
}

// MustSetContextTemplate configures contextual fields and panics if the format cannot be parsed.
func MustSetContextTemplate(config ContextConfig) {