support response metadata

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

grpc.go

@@ -78,10 +78,15 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 	} else {
 		header = make(map[string]string, 2)
 	}
-
+	if opts.RequestMetadata != nil {
+		for k, v := range opts.RequestMetadata {
+			header[k] = v
+		}
+	}
 	// set timeout in nanoseconds
 	header["Grpc-Timeout"] = fmt.Sprintf("%dn", opts.RequestTimeout)
 	header["timeout"] = fmt.Sprintf("%dn", opts.RequestTimeout)
+	header["content-type"] = req.ContentType()
 
 	md := gmetadata.New(header)
 	ctx = gmetadata.NewOutgoingContext(ctx, md)
@@ -113,7 +118,7 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 		),
 	}
 
-	if opts := g.getGrpcDialOptions(); opts != nil {
+	if opts := g.getGrpcDialOptions(opts.Context); opts != nil {
 		grpcDialOptions = append(grpcDialOptions, opts...)
 	}
 
@@ -127,15 +132,22 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 	}()
 
 	ch := make(chan error, 1)
+	var gmd gmetadata.MD
+
+	grpcCallOptions := []grpc.CallOption{
+		grpc.CallContentSubtype((&wrapMicroCodec{cf}).Name()),
+	}
+
+	if opts := g.getGrpcCallOptions(opts.Context); opts != nil {
+		grpcCallOptions = append(grpcCallOptions, opts...)
+	}
+
+	if opts.ResponseMetadata != nil {
+		gmd = gmetadata.MD{}
+		grpcCallOptions = append(grpcCallOptions, grpc.Header(&gmd))
+	}
 
 	go func() {
-		grpcCallOptions := []grpc.CallOption{
-			grpc.ForceCodec(&wrapMicroCodec{cf}),
-			grpc.CallContentSubtype((&wrapMicroCodec{cf}).Name()),
-		}
-		if opts := g.getGrpcCallOptions(); opts != nil {
-			grpcCallOptions = append(grpcCallOptions, opts...)
-		}
 		err := cc.Invoke(ctx, methodToGRPC(req.Service(), req.Endpoint()), req.Body(), rsp, grpcCallOptions...)
 		ch <- microError(err)
 	}()
@@ -147,6 +159,13 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 		grr = errors.Timeout("go.micro.client", "%v", ctx.Err())
 	}
 
+	if opts.ResponseMetadata != nil {
+		*opts.ResponseMetadata = metadata.New(gmd.Len())
+		for k, v := range gmd {
+			opts.ResponseMetadata.Set(k, strings.Join(v, ","))
+		}
+	}
+
 	return grr
 }
 
@@ -168,7 +187,7 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 		header["timeout"] = fmt.Sprintf("%dn", opts.StreamTimeout)
 	}
 	// set the content type for the request
-	header["x-content-type"] = req.ContentType()
+	header["content-type"] = req.ContentType()
 
 	md := gmetadata.New(header)
 	ctx = gmetadata.NewOutgoingContext(ctx, md)
@@ -200,7 +219,7 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 		),
 	}
 
-	if opts := g.getGrpcDialOptions(); opts != nil {
+	if opts := g.getGrpcDialOptions(opts.Context); opts != nil {
 		grpcDialOptions = append(grpcDialOptions, opts...)
 	}
 
@@ -216,12 +235,17 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 	}
 
 	grpcCallOptions := []grpc.CallOption{
-		grpc.ForceCodec(wc),
+		// grpc.ForceCodec(wc),
 		grpc.CallContentSubtype(wc.Name()),
 	}
-	if opts := g.getGrpcCallOptions(); opts != nil {
+	if opts := g.getGrpcCallOptions(opts.Context); opts != nil {
 		grpcCallOptions = append(grpcCallOptions, opts...)
 	}
+	var gmd gmetadata.MD
+	if opts.ResponseMetadata != nil {
+		gmd = gmetadata.MD{}
+		grpcCallOptions = append(grpcCallOptions, grpc.Header(&gmd))
+	}
 
 	// create a new cancelling context
 	newCtx, cancel := context.WithCancel(ctx)
@@ -267,6 +291,7 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 	// set the stream as the response
 	val := reflect.ValueOf(rsp).Elem()
 	val.Set(reflect.ValueOf(stream).Elem())
+
 	return nil
 }
 
@@ -391,6 +416,7 @@ func (g *grpcClient) Call(ctx context.Context, req client.Request, rsp interface
 	}
 	// make a copy of call opts
 	callOpts := g.opts.CallOptions
+
 	for _, opt := range opts {
 		opt(&callOpts)
 	}
@@ -728,41 +754,45 @@ func (g *grpcClient) Name() string {
 	return g.opts.Name
 }
 
-func (g *grpcClient) getGrpcDialOptions() []grpc.DialOption {
-	if g.opts.CallOptions.Context == nil {
-		return nil
+func (g *grpcClient) getGrpcDialOptions(ctx context.Context) []grpc.DialOption {
+	var opts []grpc.DialOption
+
+	if g.opts.CallOptions.Context != nil {
+		if v := g.opts.CallOptions.Context.Value(grpcDialOptions{}); v != nil {
+			if vopts, ok := v.([]grpc.DialOption); ok {
+				opts = append(opts, vopts...)
+			}
+		}
 	}
 
-	v := g.opts.CallOptions.Context.Value(grpcDialOptions{})
-
-	if v == nil {
-		return nil
-	}
-
-	opts, ok := v.([]grpc.DialOption)
-
-	if !ok {
-		return nil
+	if ctx != nil {
+		if v := ctx.Value(grpcDialOptions{}); v != nil {
+			if vopts, ok := v.([]grpc.DialOption); ok {
+				opts = append(opts, vopts...)
+			}
+		}
 	}
 
 	return opts
 }
 
-func (g *grpcClient) getGrpcCallOptions() []grpc.CallOption {
-	if g.opts.CallOptions.Context == nil {
-		return nil
+func (g *grpcClient) getGrpcCallOptions(ctx context.Context) []grpc.CallOption {
+	var opts []grpc.CallOption
+
+	if g.opts.CallOptions.Context != nil {
+		if v := g.opts.CallOptions.Context.Value(grpcCallOptions{}); v != nil {
+			if vopts, ok := v.([]grpc.CallOption); ok {
+				opts = append(opts, vopts...)
+			}
+		}
 	}
 
-	v := g.opts.CallOptions.Context.Value(grpcCallOptions{})
-
-	if v == nil {
-		return nil
-	}
-
-	opts, ok := v.([]grpc.CallOption)
-
-	if !ok {
-		return nil
+	if ctx != nil {
+		if v := ctx.Value(grpcCallOptions{}); v != nil {
+			if vopts, ok := v.([]grpc.CallOption); ok {
+				opts = append(opts, vopts...)
+			}
+		}
 	}
 
 	return opts
@@ -771,7 +801,9 @@ func (g *grpcClient) getGrpcCallOptions() []grpc.CallOption {
 func NewClient(opts ...client.Option) client.Client {
 	options := client.NewOptions(opts...)
 	// default content type for grpc
-	options.ContentType = DefaultContentType
+	if options.ContentType == "" {
+		options.ContentType = DefaultContentType
+	}
 
 	rc := &grpcClient{
 		opts: options,