core/telemetry: move requestid to pkg directory (#4911)

pkg/telemetry/requestid/grpc_client.go

@@ -0,0 +1,40 @@
+package requestid
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+// StreamClientInterceptor returns a new gRPC StreamClientInterceptor which puts the request ID in the outgoing
+// metadata.
+func StreamClientInterceptor() grpc.StreamClientInterceptor {
+	return func(ctx context.Context,
+		desc *grpc.StreamDesc, cc *grpc.ClientConn,
+		method string, streamer grpc.Streamer, opts ...grpc.CallOption,
+	) (grpc.ClientStream, error) {
+		ctx = toMetadata(ctx)
+		return streamer(ctx, desc, cc, method, opts...)
+	}
+}
+
+// UnaryClientInterceptor returns a new gRPC UnaryClientInterceptor which puts the request ID in the outgoing
+// metadata.
+func UnaryClientInterceptor() grpc.UnaryClientInterceptor {
+	return func(ctx context.Context,
+		method string, req, reply interface{},
+		cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption,
+	) error {
+		ctx = toMetadata(ctx)
+		return invoker(ctx, method, req, reply, cc, opts...)
+	}
+}
+
+func toMetadata(ctx context.Context) context.Context {
+	requestID := FromContext(ctx)
+	if requestID == "" {
+		requestID = New()
+	}
+	return metadata.AppendToOutgoingContext(ctx, headerName, requestID)
+}