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csds: return empty response if xds client is not set #4505

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merged 2 commits into from Jun 3, 2021
Merged

csds: return empty response if xds client is not set #4505

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298349c
[csds_no_error] csds: return empty response if xds client is not set
menghanl Jun 1, 2021
9b021b9
[csds_no_error] c1
menghanl Jun 2, 2021
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17 changes: 11 additions & 6 deletions xds/csds/csds.go
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Expand Up @@ -25,7 +25,6 @@ package csds

import (
"context"
"fmt"
"io"
"time"

Expand Down Expand Up @@ -76,11 +75,12 @@ type ClientStatusDiscoveryServer struct {
func NewClientStatusDiscoveryServer() (*ClientStatusDiscoveryServer, error) {
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Above, s/practise/practice/.

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Done

xdsC, err := newXDSClient()
if err != nil {
return nil, fmt.Errorf("failed to create xds client: %v", err)
logger.Warningf("failed to create xds client: %v", err)
// Return an explicit nil here, otherwise the nil returned from
// client.New() is a typed nil (type *Client, not the interface).
return &ClientStatusDiscoveryServer{}, nil
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It took me a long time to figure out what this comment means. Let's change it:

// xdsC is a typed nil here, so we if we assign it to the xdsClient field, the
// nil checks in the handlers will not handle it properly.

Or you could fix this by doing:

newXDSClient = func() (xdsClientInterface, error) {
	c, err := client.New()
	if err != nil {
		return nil, err
	}
	return c, nil
}

Or slightly better:

newXDSClient = func() xdsClientInterface {
	c, err := client.New()
	if err != nil {
		logger.Warningf(...)
		return nil
	}
	return c
}

But ACTUALLY, why do we even have newXDSClient? For testing, why not construct a ClientStatusDiscoverServer manually?

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Updated to newXDSClient = func() xdsClientInterface

But ACTUALLY, why do we even have newXDSClient? For testing, why not construct a ClientStatusDiscoverServer manually?

Why is this better? If we add more things to NewClientStatusDiscoveryServer(), they won't be covered.

}
return &ClientStatusDiscoveryServer{
xdsClient: xdsC,
}, nil
return &ClientStatusDiscoveryServer{xdsClient: xdsC}, nil
}

// StreamClientStatus implementations interface ClientStatusDiscoveryServiceServer.
Expand Down Expand Up @@ -113,6 +113,9 @@ func (s *ClientStatusDiscoveryServer) FetchClientStatus(_ context.Context, req *
//
// If it returns an error, the error is a status error.
func (s *ClientStatusDiscoveryServer) buildClientStatusRespForReq(req *v3statuspb.ClientStatusRequest) (*v3statuspb.ClientStatusResponse, error) {
if s.xdsClient == nil {
return &v3statuspb.ClientStatusResponse{}, nil
}
// 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 {
Expand All @@ -137,7 +140,9 @@ func (s *ClientStatusDiscoveryServer) buildClientStatusRespForReq(req *v3statusp

// Close cleans up the resources.
func (s *ClientStatusDiscoveryServer) Close() {
s.xdsClient.Close()
if s.xdsClient != nil {
s.xdsClient.Close()
}
}

// nodeProtoToV3 converts the given proto into a v3.Node. n is from bootstrap
Expand Down
68 changes: 68 additions & 0 deletions xds/csds/csds_test.go
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Expand Up @@ -37,6 +37,7 @@ import (
"google.golang.org/grpc/internal/testutils"
"google.golang.org/grpc/internal/xds"
"google.golang.org/grpc/xds/internal/client"
"google.golang.org/grpc/xds/internal/client/bootstrap"
_ "google.golang.org/grpc/xds/internal/httpfilter/router"
xtestutils "google.golang.org/grpc/xds/internal/testutils"
"google.golang.org/grpc/xds/internal/testutils/e2e"
Expand Down Expand Up @@ -635,6 +636,73 @@ func protoToJSON(p proto.Message) string {
return ret
}

type errorXDSClient struct{}

func (t errorXDSClient) DumpLDS() (string, map[string]client.UpdateWithMD) { panic("implement me") }
func (t errorXDSClient) DumpRDS() (string, map[string]client.UpdateWithMD) { panic("implement me") }
func (t errorXDSClient) DumpCDS() (string, map[string]client.UpdateWithMD) { panic("implement me") }
func (t errorXDSClient) DumpEDS() (string, map[string]client.UpdateWithMD) { panic("implement me") }
func (t errorXDSClient) BootstrapConfig() *bootstrap.Config { panic("implement me") }
func (t errorXDSClient) Close() { panic("implement me") }

func newErrorXDSClient() (*errorXDSClient, error) {
return nil, fmt.Errorf("typed nil")
}

func TestCSDSNoXDSClient(t *testing.T) {
oldNewXDSClient := newXDSClient
newXDSClient = func() (xdsClientInterface, error) {
return newErrorXDSClient()
}
defer func() { newXDSClient = oldNewXDSClient }()

// Initialize an gRPC server and register CSDS on it.
server := grpc.NewServer()
csdss, err := NewClientStatusDiscoveryServer()
if err != nil {
t.Fatal(err)
}
defer csdss.Close()
v3statuspbgrpc.RegisterClientStatusDiscoveryServiceServer(server, csdss)
// Create a local listener and pass it to Serve().
lis, err := xtestutils.LocalTCPListener()
if err != nil {
t.Fatalf("xtestutils.LocalTCPListener() failed: %v", err)
}
go func() {
if err := server.Serve(lis); err != nil {
t.Errorf("Serve() failed: %v", err)
}
}()
defer server.Stop()

// Create CSDS client.
conn, err := grpc.Dial(lis.Addr().String(), grpc.WithInsecure())
if err != nil {
t.Fatalf("cannot connect to server: %v", err)
}
defer conn.Close()
c := v3statuspbgrpc.NewClientStatusDiscoveryServiceClient(conn)
ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
defer cancel()
stream, err := c.StreamClientStatus(ctx, grpc.WaitForReady(true))
if err != nil {
t.Fatalf("cannot get ServerReflectionInfo: %v", err)
}

if err := stream.Send(&v3statuspb.ClientStatusRequest{Node: nil}); err != nil {
t.Fatalf("failed to send: %v", err)
}
r, err := stream.Recv()
if err != nil {
// io.EOF is not ok.
t.Fatalf("failed to recv response: %v", err)
}
if n := len(r.Config); n != 0 {
t.Fatalf("got %d configs, want 0: %v", n, proto.MarshalTextString(r))
}
}

func Test_nodeProtoToV3(t *testing.T) {
const (
testID = "test-id"
Expand Down