add the opentelemetry tracing (#908)

* add the opentelemetry tracing

* fix the error sampler config

* 添加stream的链路跟踪

* fix the error field name

core/opentelemetry/clientstream.go

@@ -0,0 +1,128 @@
+package opentelemetry
+
+import (
+	"context"
+	"io"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/protobuf/proto"
+)
+
+type streamEventType int
+
+type streamEvent struct {
+	Type streamEventType
+	Err  error
+}
+
+const (
+	receiveEndEvent streamEventType = iota
+	errorEvent
+)
+
+type clientStream struct {
+	grpc.ClientStream
+
+	desc       *grpc.StreamDesc
+	events     chan streamEvent
+	eventsDone chan struct{}
+	Finished   chan error
+
+	receivedMessageID int
+	sentMessageID     int
+}
+
+var _ = proto.Marshal
+
+func (w *clientStream) RecvMsg(m interface{}) error {
+	err := w.ClientStream.RecvMsg(m)
+
+	if err == nil && !w.desc.ServerStreams {
+		w.sendStreamEvent(receiveEndEvent, nil)
+	} else if err == io.EOF {
+		w.sendStreamEvent(receiveEndEvent, nil)
+	} else if err != nil {
+		w.sendStreamEvent(errorEvent, err)
+	} else {
+		w.receivedMessageID++
+		MessageReceived.Event(w.Context(), w.receivedMessageID, m)
+	}
+
+	return err
+}
+
+func (w *clientStream) SendMsg(m interface{}) error {
+	err := w.ClientStream.SendMsg(m)
+
+	w.sentMessageID++
+	MessageSent.Event(w.Context(), w.sentMessageID, m)
+
+	if err != nil {
+		w.sendStreamEvent(errorEvent, err)
+	}
+
+	return err
+}
+
+func (w *clientStream) Header() (metadata.MD, error) {
+	md, err := w.ClientStream.Header()
+
+	if err != nil {
+		w.sendStreamEvent(errorEvent, err)
+	}
+
+	return md, err
+}
+
+func (w *clientStream) CloseSend() error {
+	err := w.ClientStream.CloseSend()
+
+	if err != nil {
+		w.sendStreamEvent(errorEvent, err)
+	}
+
+	return err
+}
+
+func (w *clientStream) sendStreamEvent(eventType streamEventType, err error) {
+	select {
+	case <-w.eventsDone:
+	case w.events <- streamEvent{Type: eventType, Err: err}:
+	}
+}
+
+func WrapClientStream(ctx context.Context, s grpc.ClientStream, desc *grpc.StreamDesc) *clientStream {
+	events := make(chan streamEvent)
+	eventsDone := make(chan struct{})
+	finished := make(chan error)
+
+	go func() {
+		defer close(eventsDone)
+
+		for {
+			select {
+			case event := <-events:
+				switch event.Type {
+				case receiveEndEvent:
+					finished <- nil
+					return
+				case errorEvent:
+					finished <- event.Err
+					return
+				}
+			case <-ctx.Done():
+				finished <- ctx.Err()
+				return
+			}
+		}
+	}()
+
+	return &clientStream{
+		ClientStream: s,
+		desc:         desc,
+		events:       events,
+		eventsDone:   eventsDone,
+		Finished:     finished,
+	}
+}