add chain hop

hosts/hosts.go

@@ -23,6 +23,7 @@ type options struct {
 	mappings    []Mapping
 	fileLoader  loader.Loader
 	redisLoader loader.Loader
+	httpLoader  loader.Loader
 	period      time.Duration
 	logger      logger.Logger
 }
@@ -53,6 +54,12 @@ func RedisLoaderOption(redisLoader loader.Loader) Option {
 	}
 }
 
+func HTTPLoaderOption(httpLoader loader.Loader) Option {
+	return func(opts *options) {
+		opts.httpLoader = httpLoader
+	}
+}
+
 func LoggerOption(logger logger.Logger) Option {
 	return func(opts *options) {
 		opts.logger = logger
@@ -254,6 +261,15 @@ func (h *hostMapper) load(ctx context.Context) (mappings []Mapping, err error) {
 			}
 		}
 	}
+	if h.options.httpLoader != nil {
+		r, er := h.options.httpLoader.Load(ctx)
+		if er != nil {
+			h.options.logger.Warnf("http loader: %v", er)
+		}
+		if m, _ := h.parseMapping(r); m != nil {
+			mappings = append(mappings, m...)
+		}
+	}
 
 	h.options.logger.Debugf("load items %d", len(mappings))
 	return