chore: import upstream snapshot with attribution

server/grpc/subscriber.go

@@ -0,0 +1,291 @@
+package grpc
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"runtime/debug"
+	"strings"
+
+	"go-micro.dev/v6/broker"
+	"go-micro.dev/v6/errors"
+	"go-micro.dev/v6/logger"
+	"go-micro.dev/v6/metadata"
+	"go-micro.dev/v6/registry"
+	"go-micro.dev/v6/server"
+)
+
+const (
+	subSig = "func(context.Context, interface{}) error"
+)
+
+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       server.SubscriberOptions
+}
+
+func newSubscriber(topic string, sub interface{}, opts ...server.SubscriberOption) server.Subscriber {
+	options := server.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, &registry.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, &registry.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 server.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 (g *grpcServer) createSubHandler(sb *subscriber, opts server.Options) broker.Handler {
+	return func(p broker.Event) (err error) {
+		defer func() {
+			if r := recover(); r != nil {
+				g.opts.Logger.Log(logger.ErrorLevel, "panic recovered: ", r)
+				g.opts.Logger.Log(logger.ErrorLevel, string(debug.Stack()))
+				err = errors.InternalServerError("go.micro.server", "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 := g.newGRPCCodec(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(context.Background(), 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.Pointer {
+				req = reflect.New(handler.reqType.Elem())
+			} else {
+				req = reflect.New(handler.reqType)
+				isVal = true
+			}
+			if isVal {
+				req = req.Elem()
+			}
+
+			if err = cf.Unmarshal(msg.Body, req.Interface()); err != nil {
+				return err
+			}
+
+			fn := func(ctx context.Context, msg server.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 g.wg != nil {
+				g.wg.Add(1)
+			}
+			go func() {
+				if g.wg != nil {
+					defer g.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() server.SubscriberOptions {
+	return s.opts
+}