Function RequestIDHandler

hlog/hlog.go:214–236

RequestIDHandler returns a handler setting a unique id to the request which can be gathered using IDFromRequest(req). This generated id is added as a field to the logger using the passed fieldKey as field name. The id is also added as a response header if the headerName is not empty. The generated

(fieldKey, headerName string)

// size and ease of use: UUID is less space efficient and snowflake requires machine
// configuration.
func RequestIDHandler(fieldKey, headerName string) func(next http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()
			id, ok := IDFromRequest(r)
			if !ok {
				id = xid.New()
				ctx = CtxWithID(ctx, id)
				r = r.WithContext(ctx)
			}
			if fieldKey != "" {
				log := zerolog.Ctx(ctx)
				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
					return c.Str(fieldKey, id.String())
				})
			}
			if headerName != "" {
				w.Header().Set(headerName, id.String())
			}
			next.ServeHTTP(w, r)
		})
	}
}

// CustomHeaderHandler adds given header from request's header as a field to
// the context's logger using fieldKey as field key.