interceptors: migrate to otel and add logging interceptor

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

example/server.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+	"google.golang.org/grpc"
+
+	"go.linka.cloud/grpc-tookit/example/pb"
+	"go.linka.cloud/grpc-toolkit/interceptors/iface"
+	"go.linka.cloud/grpc-toolkit/logger"
+)
+
+var (
+	_ iface.UnaryInterceptor  = (*GreeterHandler)(nil)
+	_ iface.StreamInterceptor = (*GreeterHandler)(nil)
+)
+
+type GreeterHandler struct {
+	pb.UnimplementedGreeterServer
+}
+
+func hello(name string) string {
+	return fmt.Sprintf("Hello %s !", name)
+}
+
+func (g *GreeterHandler) SayHello(ctx context.Context, req *pb.HelloRequest) (*pb.HelloReply, error) {
+	span := trace.SpanFromContext(ctx)
+	span.SetAttributes(attribute.String("name", req.Name))
+	logger.C(ctx).Infof("replying to %s", req.Name)
+	return &pb.HelloReply{Message: hello(req.Name)}, nil
+}
+
+func (g *GreeterHandler) SayHelloStream(req *pb.HelloStreamRequest, s pb.Greeter_SayHelloStreamServer) error {
+	log := logger.C(s.Context())
+	for i := int64(0); i < req.Count; i++ {
+		log.Infof("sending message %d", i+1)
+		if err := s.Send(&pb.HelloReply{Message: fmt.Sprintf("Hello %s (%d)!", req.Name, i+1)}); err != nil {
+			return err
+		}
+		// time.Sleep(time.Second)
+	}
+	return nil
+}
+
+func (g *GreeterHandler) UnaryServerInterceptor() grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
+		logger.C(ctx).Infof("called service interface unary interceptor")
+		return handler(ctx, req)
+	}
+}
+
+func (g *GreeterHandler) StreamServerInterceptor() grpc.StreamServerInterceptor {
+	return func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		logger.C(ss.Context()).Infof("called service interface stream interceptor")
+		return handler(srv, ss)
+	}
+}