Support endpoint metadata

server/handler.go

@@ -34,6 +34,7 @@ type Subscriber interface {
 
 type HandlerOptions struct {
 	Internal bool
+	Metadata map[string]map[string]string
 }
 
 type SubscriberOptions struct {
@@ -50,6 +51,14 @@ func InternalHandler(b bool) HandlerOption {
 	}
 }
 
+// EndpointMetadata is a Handler option that allows metadata to be added to
+// individual endpoints.
+func EndpointMetadata(endpoint string, metadata map[string]string) HandlerOption {
+	return func(o *HandlerOptions) {
+		o.Metadata[endpoint] = metadata
+	}
+}
+
 // Internal Subscriber options specifies that a subscriber is not advertised
 // to the discovery system.
 func InternalSubscriber(b bool) SubscriberOption {

server/rpc_handler.go

@@ -14,7 +14,10 @@ type rpcHandler struct {
 }
 
 func newRpcHandler(handler interface{}, opts ...HandlerOption) Handler {
-	var options HandlerOptions
+	options := HandlerOptions{
+		Metadata: make(map[string]map[string]string),
+	}
+
 	for _, o := range opts {
 		o(&options)
 	}
@@ -28,6 +31,11 @@ func newRpcHandler(handler interface{}, opts ...HandlerOption) Handler {
 	for m := 0; m < typ.NumMethod(); m++ {
 		if e := extractEndpoint(typ.Method(m)); e != nil {
 			e.Name = name + "." + e.Name
+
+			for k, v := range options.Metadata[e.Name] {
+				e.Metadata[k] = v
+			}
+
 			endpoints = append(endpoints, e)
 		}
 	}