snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

xds/csds/csds.go

@@ -0,0 +1,108 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package csds implements features to dump the status (xDS responses) the
+// xds_client is using.
+//
+// Notice: This package is EXPERIMENTAL and may be changed or removed in a later
+// release.
+package csds
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/grpclog"
+	internalgrpclog "google.golang.org/grpc/internal/grpclog"
+	"google.golang.org/grpc/internal/xds/xdsclient"
+	"google.golang.org/grpc/status"
+
+	v3statusgrpc "github.com/envoyproxy/go-control-plane/envoy/service/status/v3"
+	v3statuspb "github.com/envoyproxy/go-control-plane/envoy/service/status/v3"
+)
+
+var logger = grpclog.Component("xds")
+
+const prefix = "[csds-server %p] "
+
+func prefixLogger(s *ClientStatusDiscoveryServer) *internalgrpclog.PrefixLogger {
+	return internalgrpclog.NewPrefixLogger(logger, fmt.Sprintf(prefix, s))
+}
+
+// ClientStatusDiscoveryServer provides an implementation of the Client Status
+// Discovery Service (CSDS) for exposing the xDS config of a given client. See
+// https://github.com/envoyproxy/envoy/blob/main/api/envoy/service/status/v3/csds.proto.
+//
+// For more details about the gRPC implementation of CSDS, refer to gRPC A40 at:
+// https://github.com/grpc/proposal/blob/master/A40-csds-support.md.
+type ClientStatusDiscoveryServer struct {
+	logger *internalgrpclog.PrefixLogger
+}
+
+// NewClientStatusDiscoveryServer returns an implementation of the CSDS server
+// that can be registered on a gRPC server.
+func NewClientStatusDiscoveryServer() (*ClientStatusDiscoveryServer, error) {
+	s := &ClientStatusDiscoveryServer{}
+	s.logger = prefixLogger(s)
+	s.logger.Infof("Created CSDS server")
+	return s, nil
+}
+
+// StreamClientStatus implements interface ClientStatusDiscoveryServiceServer.
+func (s *ClientStatusDiscoveryServer) StreamClientStatus(stream v3statusgrpc.ClientStatusDiscoveryService_StreamClientStatusServer) error {
+	for {
+		req, err := stream.Recv()
+		if err == io.EOF {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+		resp, err := s.buildClientStatusRespForReq(req)
+		if err != nil {
+			return err
+		}
+		if err := stream.Send(resp); err != nil {
+			return err
+		}
+	}
+}
+
+// FetchClientStatus implements interface ClientStatusDiscoveryServiceServer.
+func (s *ClientStatusDiscoveryServer) FetchClientStatus(_ context.Context, req *v3statuspb.ClientStatusRequest) (*v3statuspb.ClientStatusResponse, error) {
+	return s.buildClientStatusRespForReq(req)
+}
+
+// buildClientStatusRespForReq fetches the status of xDS resources from the
+// xdsclient, and returns the response to be sent back to the csds client.
+//
+// If it returns an error, the error is a status error.
+func (s *ClientStatusDiscoveryServer) buildClientStatusRespForReq(req *v3statuspb.ClientStatusRequest) (*v3statuspb.ClientStatusResponse, error) {
+	// Field NodeMatchers is unsupported, by design
+	// https://github.com/grpc/proposal/blob/master/A40-csds-support.md#detail-node-matching.
+	if len(req.NodeMatchers) != 0 {
+		return nil, status.Errorf(codes.InvalidArgument, "node_matchers are not supported, request contains node_matchers: %v", req.NodeMatchers)
+	}
+
+	return xdsclient.DumpResources(), nil
+}
+
+// Close cleans up the resources.
+func (s *ClientStatusDiscoveryServer) Close() {}