316 lines
7.4 KiB
Go
316 lines
7.4 KiB
Go
package server
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import (
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"bytes"
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"context"
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"fmt"
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"reflect"
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"runtime/debug"
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"strings"
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"unicode"
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"unicode/utf8"
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"github.com/unistack-org/micro/v3/broker"
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"github.com/unistack-org/micro/v3/errors"
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"github.com/unistack-org/micro/v3/logger"
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"github.com/unistack-org/micro/v3/metadata"
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"github.com/unistack-org/micro/v3/registry"
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)
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const (
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subSig = "func(context.Context, interface{}) error"
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)
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var (
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// Precompute the reflect type for error. Can't use error directly
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// because Typeof takes an empty interface value. This is annoying.
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typeOfError = reflect.TypeOf((*error)(nil)).Elem()
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)
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type handler struct {
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method reflect.Value
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reqType reflect.Type
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ctxType reflect.Type
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}
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type subscriber struct {
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topic string
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rcvr reflect.Value
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typ reflect.Type
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subscriber interface{}
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handlers []*handler
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endpoints []*registry.Endpoint
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opts SubscriberOptions
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}
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// Is this an exported - upper case - name?
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func isExported(name string) bool {
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rune, _ := utf8.DecodeRuneInString(name)
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return unicode.IsUpper(rune)
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}
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// Is this type exported or a builtin?
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func isExportedOrBuiltinType(t reflect.Type) bool {
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for t.Kind() == reflect.Ptr {
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t = t.Elem()
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}
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// PkgPath will be non-empty even for an exported type,
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// so we need to check the type name as well.
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return isExported(t.Name()) || t.PkgPath() == ""
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}
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// ValidateSubscriber func
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func ValidateSubscriber(sub Subscriber) error {
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typ := reflect.TypeOf(sub.Subscriber())
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var argType reflect.Type
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if typ.Kind() == reflect.Func {
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name := "Func"
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switch typ.NumIn() {
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case 2:
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argType = typ.In(1)
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default:
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return fmt.Errorf("subscriber %v takes wrong number of args: %v required signature %s", name, typ.NumIn(), subSig)
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}
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if !isExportedOrBuiltinType(argType) {
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return fmt.Errorf("subscriber %v argument type not exported: %v", name, argType)
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}
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if typ.NumOut() != 1 {
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return fmt.Errorf("subscriber %v has wrong number of outs: %v require signature %s",
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name, typ.NumOut(), subSig)
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}
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if returnType := typ.Out(0); returnType != typeOfError {
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return fmt.Errorf("subscriber %v returns %v not error", name, returnType.String())
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}
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} else {
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hdlr := reflect.ValueOf(sub.Subscriber())
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name := reflect.Indirect(hdlr).Type().Name()
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for m := 0; m < typ.NumMethod(); m++ {
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method := typ.Method(m)
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switch method.Type.NumIn() {
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case 3:
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argType = method.Type.In(2)
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default:
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return fmt.Errorf("subscriber %v.%v takes wrong number of args: %v required signature %s",
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name, method.Name, method.Type.NumIn(), subSig)
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}
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if !isExportedOrBuiltinType(argType) {
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return fmt.Errorf("%v argument type not exported: %v", name, argType)
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}
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if method.Type.NumOut() != 1 {
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return fmt.Errorf(
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"subscriber %v.%v has wrong number of outs: %v require signature %s",
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name, method.Name, method.Type.NumOut(), subSig)
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}
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if returnType := method.Type.Out(0); returnType != typeOfError {
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return fmt.Errorf("subscriber %v.%v returns %v not error", name, method.Name, returnType.String())
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}
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}
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}
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return nil
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}
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func newSubscriber(topic string, sub interface{}, opts ...SubscriberOption) Subscriber {
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var endpoints []*registry.Endpoint
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var handlers []*handler
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options := NewSubscriberOptions(opts...)
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if typ := reflect.TypeOf(sub); typ.Kind() == reflect.Func {
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h := &handler{
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method: reflect.ValueOf(sub),
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}
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switch typ.NumIn() {
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case 1:
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h.reqType = typ.In(0)
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case 2:
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h.ctxType = typ.In(0)
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h.reqType = typ.In(1)
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}
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handlers = append(handlers, h)
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endpoints = append(endpoints, ®istry.Endpoint{
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Name: "Func",
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Request: registry.ExtractSubValue(typ),
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Metadata: map[string]string{
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"topic": topic,
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"subscriber": "true",
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},
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})
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} else {
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hdlr := reflect.ValueOf(sub)
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name := reflect.Indirect(hdlr).Type().Name()
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for m := 0; m < typ.NumMethod(); m++ {
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method := typ.Method(m)
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h := &handler{
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method: method.Func,
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}
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switch method.Type.NumIn() {
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case 2:
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h.reqType = method.Type.In(1)
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case 3:
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h.ctxType = method.Type.In(1)
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h.reqType = method.Type.In(2)
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}
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handlers = append(handlers, h)
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endpoints = append(endpoints, ®istry.Endpoint{
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Name: name + "." + method.Name,
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Request: registry.ExtractSubValue(method.Type),
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Metadata: map[string]string{
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"topic": topic,
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"subscriber": "true",
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},
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})
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}
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}
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return &subscriber{
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rcvr: reflect.ValueOf(sub),
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typ: reflect.TypeOf(sub),
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topic: topic,
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subscriber: sub,
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handlers: handlers,
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endpoints: endpoints,
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opts: options,
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}
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}
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func (n *noopServer) createSubHandler(sb *subscriber, opts Options) broker.Handler {
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return func(p broker.Event) (err error) {
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defer func() {
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if r := recover(); r != nil {
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n.RLock()
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config := n.opts
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n.RUnlock()
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if config.Logger.V(logger.ErrorLevel) {
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config.Logger.Error("panic recovered: ", r)
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config.Logger.Error(string(debug.Stack()))
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}
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err = errors.InternalServerError(n.opts.Name+".subscriber", "panic recovered: %v", r)
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}
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}()
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msg := p.Message()
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// if we don't have headers, create empty map
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if msg.Header == nil {
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msg.Header = make(map[string]string)
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}
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ct := msg.Header["Content-Type"]
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if len(ct) == 0 {
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msg.Header["Content-Type"] = defaultContentType
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ct = defaultContentType
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}
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cf, err := n.newCodec(ct)
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if err != nil {
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return err
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}
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hdr := make(map[string]string, len(msg.Header))
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for k, v := range msg.Header {
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hdr[k] = v
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}
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delete(hdr, "Content-Type")
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ctx := metadata.NewContext(sb.opts.Context, hdr)
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results := make(chan error, len(sb.handlers))
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for i := 0; i < len(sb.handlers); i++ {
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handler := sb.handlers[i]
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var isVal bool
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var req reflect.Value
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if handler.reqType.Kind() == reflect.Ptr {
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req = reflect.New(handler.reqType.Elem())
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} else {
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req = reflect.New(handler.reqType)
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isVal = true
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}
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if isVal {
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req = req.Elem()
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}
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if err = cf(noopcodec{bytes.NewBuffer(msg.Body)}).ReadBody(req.Interface()); err != nil {
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return err
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}
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fn := func(ctx context.Context, msg Message) error {
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var vals []reflect.Value
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if sb.typ.Kind() != reflect.Func {
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vals = append(vals, sb.rcvr)
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}
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if handler.ctxType != nil {
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vals = append(vals, reflect.ValueOf(ctx))
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}
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vals = append(vals, reflect.ValueOf(msg.Payload()))
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returnValues := handler.method.Call(vals)
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if rerr := returnValues[0].Interface(); rerr != nil {
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return rerr.(error)
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}
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return nil
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}
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for i := len(opts.SubWrappers); i > 0; i-- {
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fn = opts.SubWrappers[i-1](fn)
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}
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if n.wg != nil {
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n.wg.Add(1)
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}
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go func() {
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if n.wg != nil {
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defer n.wg.Done()
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}
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err := fn(ctx, &rpcMessage{
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topic: sb.topic,
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contentType: ct,
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payload: req.Interface(),
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header: msg.Header,
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body: msg.Body,
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})
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results <- err
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}()
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}
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var errors []string
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for i := 0; i < len(sb.handlers); i++ {
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if rerr := <-results; rerr != nil {
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errors = append(errors, rerr.Error())
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}
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}
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if len(errors) > 0 {
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err = fmt.Errorf("subscriber error: %s", strings.Join(errors, "\n"))
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}
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return err
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}
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}
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func (s *subscriber) Topic() string {
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return s.topic
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}
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func (s *subscriber) Subscriber() interface{} {
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return s.subscriber
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}
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func (s *subscriber) Endpoints() []*registry.Endpoint {
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return s.endpoints
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}
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func (s *subscriber) Options() SubscriberOptions {
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return s.opts
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}
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