package server import ( "fmt" "reflect" "go-micro.dev/v5/registry" ) const ( subSig = "func(context.Context, interface{}) error" ) type handler struct { reqType reflect.Type ctxType reflect.Type method reflect.Value } type subscriber struct { opts SubscriberOptions typ reflect.Type subscriber interface{} rcvr reflect.Value topic string handlers []*handler endpoints []*registry.Endpoint } func newSubscriber(topic string, sub interface{}, opts ...SubscriberOption) Subscriber { options := SubscriberOptions{ AutoAck: true, } for _, o := range opts { o(&options) } var endpoints []*registry.Endpoint var handlers []*handler if typ := reflect.TypeOf(sub); typ.Kind() == reflect.Func { h := &handler{ method: reflect.ValueOf(sub), } switch typ.NumIn() { case 1: h.reqType = typ.In(0) case 2: h.ctxType = typ.In(0) h.reqType = typ.In(1) } handlers = append(handlers, h) endpoints = append(endpoints, ®istry.Endpoint{ Name: "Func", Request: extractSubValue(typ), Metadata: map[string]string{ "topic": topic, "subscriber": "true", }, }) } else { hdlr := reflect.ValueOf(sub) name := reflect.Indirect(hdlr).Type().Name() for m := 0; m < typ.NumMethod(); m++ { method := typ.Method(m) h := &handler{ method: method.Func, } switch method.Type.NumIn() { case 2: h.reqType = method.Type.In(1) case 3: h.ctxType = method.Type.In(1) h.reqType = method.Type.In(2) } handlers = append(handlers, h) endpoints = append(endpoints, ®istry.Endpoint{ Name: name + "." + method.Name, Request: extractSubValue(method.Type), Metadata: map[string]string{ "topic": topic, "subscriber": "true", }, }) } } return &subscriber{ rcvr: reflect.ValueOf(sub), typ: reflect.TypeOf(sub), topic: topic, subscriber: sub, handlers: handlers, endpoints: endpoints, opts: options, } } func validateSubscriber(sub Subscriber) error { typ := reflect.TypeOf(sub.Subscriber()) var argType reflect.Type if typ.Kind() == reflect.Func { name := "Func" switch typ.NumIn() { case 2: argType = typ.In(1) default: return fmt.Errorf("subscriber %v takes wrong number of args: %v required signature %s", name, typ.NumIn(), subSig) } if !isExportedOrBuiltinType(argType) { return fmt.Errorf("subscriber %v argument type not exported: %v", name, argType) } if typ.NumOut() != 1 { return fmt.Errorf("subscriber %v has wrong number of outs: %v require signature %s", name, typ.NumOut(), subSig) } if returnType := typ.Out(0); returnType != typeOfError { return fmt.Errorf("subscriber %v returns %v not error", name, returnType.String()) } } else { hdlr := reflect.ValueOf(sub.Subscriber()) name := reflect.Indirect(hdlr).Type().Name() for m := 0; m < typ.NumMethod(); m++ { method := typ.Method(m) switch method.Type.NumIn() { case 3: argType = method.Type.In(2) default: return fmt.Errorf("subscriber %v.%v takes wrong number of args: %v required signature %s", name, method.Name, method.Type.NumIn(), subSig) } if !isExportedOrBuiltinType(argType) { return fmt.Errorf("%v argument type not exported: %v", name, argType) } if method.Type.NumOut() != 1 { return fmt.Errorf( "subscriber %v.%v has wrong number of outs: %v require signature %s", name, method.Name, method.Type.NumOut(), subSig) } if returnType := method.Type.Out(0); returnType != typeOfError { return fmt.Errorf("subscriber %v.%v returns %v not error", name, method.Name, returnType.String()) } } } return nil } func (s *subscriber) Topic() string { return s.topic } func (s *subscriber) Subscriber() interface{} { return s.subscriber } func (s *subscriber) Endpoints() []*registry.Endpoint { return s.endpoints } func (s *subscriber) Options() SubscriberOptions { return s.opts }