package server import ( "bytes" "context" "fmt" "reflect" "runtime/debug" "strings" "unicode" "unicode/utf8" "github.com/unistack-org/micro/v3/broker" "github.com/unistack-org/micro/v3/errors" "github.com/unistack-org/micro/v3/logger" "github.com/unistack-org/micro/v3/metadata" "github.com/unistack-org/micro/v3/registry" ) const ( subSig = "func(context.Context, interface{}) error" ) var ( // Precompute the reflect type for error. Can't use error directly // because Typeof takes an empty interface value. This is annoying. typeOfError = reflect.TypeOf((*error)(nil)).Elem() ) type handler struct { method reflect.Value reqType reflect.Type ctxType reflect.Type } type subscriber struct { topic string rcvr reflect.Value typ reflect.Type subscriber interface{} handlers []*handler endpoints []*registry.Endpoint opts SubscriberOptions } // Is this an exported - upper case - name? func isExported(name string) bool { rune, _ := utf8.DecodeRuneInString(name) return unicode.IsUpper(rune) } // Is this type exported or a builtin? func isExportedOrBuiltinType(t reflect.Type) bool { for t.Kind() == reflect.Ptr { t = t.Elem() } // PkgPath will be non-empty even for an exported type, // so we need to check the type name as well. return isExported(t.Name()) || t.PkgPath() == "" } // ValidateSubscriber func 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 newSubscriber(topic string, sub interface{}, opts ...SubscriberOption) Subscriber { var endpoints []*registry.Endpoint var handlers []*handler options := NewSubscriberOptions(opts...) 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) ep := ®istry.Endpoint{ Name: "Func", Request: registry.ExtractSubValue(typ), Metadata: metadata.New(2), } ep.Metadata.Set("topic", topic) ep.Metadata.Set("subscriber", "true") endpoints = append(endpoints, ep) } 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) ep := ®istry.Endpoint{ Name: name + "." + method.Name, Request: registry.ExtractSubValue(method.Type), Metadata: metadata.New(2), } ep.Metadata.Set("topic", topic) ep.Metadata.Set("subscriber", "true") endpoints = append(endpoints, ep) } } return &subscriber{ rcvr: reflect.ValueOf(sub), typ: reflect.TypeOf(sub), topic: topic, subscriber: sub, handlers: handlers, endpoints: endpoints, opts: options, } } func (n *noopServer) createSubHandler(sb *subscriber, opts Options) broker.Handler { return func(p broker.Event) (err error) { defer func() { if r := recover(); r != nil { n.RLock() config := n.opts n.RUnlock() if config.Logger.V(logger.ErrorLevel) { config.Logger.Error("panic recovered: ", r) config.Logger.Error(string(debug.Stack())) } err = errors.InternalServerError(n.opts.Name+".subscriber", "panic recovered: %v", r) } }() msg := p.Message() // if we don't have headers, create empty map if msg.Header == nil { msg.Header = make(map[string]string) } ct := msg.Header["Content-Type"] if len(ct) == 0 { msg.Header["Content-Type"] = defaultContentType ct = defaultContentType } cf, err := n.newCodec(ct) if err != nil { return err } hdr := make(map[string]string, len(msg.Header)) for k, v := range msg.Header { hdr[k] = v } delete(hdr, "Content-Type") ctx := metadata.NewContext(sb.opts.Context, hdr) results := make(chan error, len(sb.handlers)) for i := 0; i < len(sb.handlers); i++ { handler := sb.handlers[i] var isVal bool var req reflect.Value if handler.reqType.Kind() == reflect.Ptr { req = reflect.New(handler.reqType.Elem()) } else { req = reflect.New(handler.reqType) isVal = true } if isVal { req = req.Elem() } if err = cf.ReadBody(bytes.NewBuffer(msg.Body), req.Interface()); err != nil { return err } fn := func(ctx context.Context, msg Message) error { var vals []reflect.Value if sb.typ.Kind() != reflect.Func { vals = append(vals, sb.rcvr) } if handler.ctxType != nil { vals = append(vals, reflect.ValueOf(ctx)) } vals = append(vals, reflect.ValueOf(msg.Payload())) returnValues := handler.method.Call(vals) if rerr := returnValues[0].Interface(); rerr != nil { return rerr.(error) } return nil } for i := len(opts.SubWrappers); i > 0; i-- { fn = opts.SubWrappers[i-1](fn) } if n.wg != nil { n.wg.Add(1) } go func() { if n.wg != nil { defer n.wg.Done() } err := fn(ctx, &rpcMessage{ topic: sb.topic, contentType: ct, payload: req.Interface(), header: msg.Header, body: msg.Body, }) results <- err }() } var errors []string for i := 0; i < len(sb.handlers); i++ { if rerr := <-results; rerr != nil { errors = append(errors, rerr.Error()) } } if len(errors) > 0 { err = fmt.Errorf("subscriber error: %s", strings.Join(errors, "\n")) } return err } } 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 }