Repository: grpc/grpc-go

Issue:
Node ID should be available in RPC errors
1. Include node ID with all xdsclient errors possible

2. Audit all possible ways an xds-enabled gRPC channel can fail as a result of xdsclient problems, and ensure the xdsclient error is propagated to RPC errors


Discussion:
@dfawley: @easwars can you help scope this, please?@easwars: I suggest making the following changes:

- [x] The watch resource API call on the xDS client can fail for a bunch of reasons. We need to include the node ID in all these errors:
  - [x] A resource type implementation was already registered.
  - [x] Authority in the resource name is not found in the bootstrap configuration.
  - [x] Creation of transport to the management server fails.
- [x] A resource is NACKed:
  - [x] The `OnError` callback needs to include the xDS node ID in the returned error.
  - [x] The error is also stored in the cache to return to future watchers. This should include the xDS node ID as well.  
- [x] Reporting connectivity failures from xDS client to watchers. xDS node id should be part of these errors.
- [x] CDS lb policy needs to include the xDS node id in errors
  - [x] Requested resource is not found
  - [x] Sends a resolver error to child policy or puts the channel in TF
- [x] xDS resolver needs to include the xDS node id in the following cases
  - [x] Error reported to the channel (when requested resource is not found)
  - [x] Error reported from the config selector
- [x] xDS server needs to include the xDS node id when it puts the server in non-serving mode
- [x] All resource watchers' `OnResourceDoesNotExist` callback should include the xDS node id if they are throwing a log. Also, these logs should not be `Info` protected with a verbosity check, but should be `Warning` logs since resource not found is usually something that is worth sharing with the user by default. 

Solution patch:
diff --git a/xds/internal/xdsclient/authority.go b/xds/internal/xdsclient/authority.go
index d9269821..05c3e49b 100644
--- a/xds/internal/xdsclient/authority.go
+++ b/xds/internal/xdsclient/authority.go
@@ -604,8 +604,9 @@ func (a *authority) watchResource(rType xdsresource.Type, resourceName string, w
 			a.logger.Infof("New watch for type %q, resource name %q", rType.TypeName(), resourceName)
 		}
 
-		xdsChannel := a.xdsChannelToUse()
-		if xdsChannel == nil {
+		xdsChannel, err := a.xdsChannelToUse()
+		if err != nil {
+			a.watcherCallbackSerializer.TrySchedule(func(context.Context) { watcher.OnError(err, func() {}) })
 			return
 		}
 
@@ -739,22 +740,23 @@ func (a *authority) unwatchResource(rType xdsresource.Type, resourceName string,
 // Otherwise, it creates a new channel using the first server configuration in
 // the list of configurations, and returns that.
 //
+// A non-nil error is returned if the channel creation fails.
+//
 // Only executed in the context of a serializer callback.
-func (a *authority) xdsChannelToUse() *xdsChannelWithConfig {
+func (a *authority) xdsChannelToUse() (*xdsChannelWithConfig, error) {
 	if a.activeXDSChannel != nil {
-		return a.activeXDSChannel
+		return a.activeXDSChannel, nil
 	}
 
 	sc := a.xdsChannelConfigs[0].serverConfig
 	xc, cleanup, err := a.getChannelForADS(sc, a)
 	if err != nil {
-		a.logger.Warningf("Failed to create xDS channel: %v", err)
-		return nil
+		return nil, err
 	}
 	a.xdsChannelConfigs[0].channel = xc
 	a.xdsChannelConfigs[0].cleanup = cleanup
 	a.activeXDSChannel = a.xdsChannelConfigs[0]
-	return a.activeXDSChannel
+	return a.activeXDSChannel, nil
 }
 
 // closeXDSChannels closes all the xDS channels associated with this authority,
diff --git a/xds/internal/xdsclient/clientimpl_watchers.go b/xds/internal/xdsclient/clientimpl_watchers.go
index ed4ee360..cc8e0849 100644
--- a/xds/internal/xdsclient/clientimpl_watchers.go
+++ b/xds/internal/xdsclient/clientimpl_watchers.go
@@ -26,6 +26,17 @@ import (
 	"google.golang.org/grpc/xds/internal/xdsclient/xdsresource"
 )
 
+// wrappingWatcher is a wrapper around an xdsresource.ResourceWatcher that adds
+// the node ID to the error messages reported to the watcher.
+type wrappingWatcher struct {
+	xdsresource.ResourceWatcher
+	nodeID string
+}
+
+func (w *wrappingWatcher) OnError(err error, done xdsresource.OnDoneFunc) {
+	w.ResourceWatcher.OnError(fmt.Errorf("[xDS node id: %v]: %v", w.nodeID, err), done)
+}
+
 // WatchResource uses xDS to discover the resource associated with the provided
 // resource name. The resource type implementation determines how xDS responses
 // are are deserialized and validated, as received from the xDS management
@@ -43,6 +54,11 @@ func (c *clientImpl) WatchResource(rType xdsresource.Type, resourceName string,
 		return func() {}
 	}
 
+	watcher = &wrappingWatcher{
+		ResourceWatcher: watcher,
+		nodeID:          c.config.Node().GetId(),
+	}
+
 	if err := c.resourceTypes.maybeRegister(rType); err != nil {
 		logger.Warningf("Watch registered for name %q of type %q which is already registered", rType.TypeName(), resourceName)
 		c.serializer.TrySchedule(func(context.Context) { watcher.OnError(err, func() {}) })
@@ -53,9 +69,7 @@ func (c *clientImpl) WatchResource(rType xdsresource.Type, resourceName string,
 	a := c.getAuthorityForResource(n)
 	if a == nil {
 		logger.Warningf("Watch registered for name %q of type %q, authority %q is not found", rType.TypeName(), resourceName, n.Authority)
-		c.serializer.TrySchedule(func(context.Context) {
-			watcher.OnError(fmt.Errorf("authority %q not found in bootstrap config for resource %q", n.Authority, resourceName), func() {})
-		})
+		watcher.OnError(fmt.Errorf("authority %q not found in bootstrap config for resource %q", n.Authority, resourceName), func() {})
 		return func() {}
 	}
 	// The watchResource method on the authority is invoked with n.String()



Test patch:
diff --git a/xds/internal/xdsclient/tests/misc_watchers_test.go b/xds/internal/xdsclient/tests/misc_watchers_test.go
index a11661f2..3fcb20bd 100644
--- a/xds/internal/xdsclient/tests/misc_watchers_test.go
+++ b/xds/internal/xdsclient/tests/misc_watchers_test.go
@@ -22,9 +22,11 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"strings"
 	"testing"
 
 	"github.com/google/uuid"
+	"google.golang.org/grpc"
 	"google.golang.org/grpc/internal/testutils"
 	"google.golang.org/grpc/internal/testutils/xds/e2e"
 	"google.golang.org/grpc/internal/testutils/xds/fakeserver"
@@ -32,6 +34,7 @@ import (
 	"google.golang.org/grpc/xds/internal"
 	xdstestutils "google.golang.org/grpc/xds/internal/testutils"
 	"google.golang.org/grpc/xds/internal/xdsclient"
+	xdsclientinternal "google.golang.org/grpc/xds/internal/xdsclient/internal"
 	"google.golang.org/grpc/xds/internal/xdsclient/xdsresource"
 	"google.golang.org/grpc/xds/internal/xdsclient/xdsresource/version"
 	"google.golang.org/protobuf/types/known/anypb"
@@ -371,3 +374,135 @@ func readDiscoveryResponseAndCheckForNonEmptyNodeProto(ctx context.Context, reqC
 	}
 	return nil
 }
+
+type testRouteConfigResourceType struct{}
+
+func (testRouteConfigResourceType) TypeURL() string                  { return version.V3RouteConfigURL }
+func (testRouteConfigResourceType) TypeName() string                 { return "RouteConfigResource" }
+func (testRouteConfigResourceType) AllResourcesRequiredInSotW() bool { return false }
+func (testRouteConfigResourceType) Decode(*xdsresource.DecodeOptions, *anypb.Any) (*xdsresource.DecodeResult, error) {
+	return nil, nil
+}
+
+// Tests that the errors returned by the xDS client when watching a resource
+// contain the node ID that was used to create the client. This test covers two
+// scenarios:
+//
+//  1. When a watch is registered for an already registered resource type, but
+//     this time with a different implementation,
+//  2. When a watch is registered for a resource name whose authority is not
+//     found in the bootstrap configuration.
+func (s) TestWatchErrorsContainNodeID(t *testing.T) {
+	mgmtServer := e2e.StartManagementServer(t, e2e.ManagementServerOptions{})
+
+	// Create bootstrap configuration pointing to the above management server.
+	nodeID := uuid.New().String()
+	bc := e2e.DefaultBootstrapContents(t, nodeID, mgmtServer.Address)
+
+	// Create an xDS client with the above bootstrap contents.
+	config, err := bootstrap.NewConfigFromContents(bc)
+	if err != nil {
+		t.Fatalf("Failed to parse bootstrap contents: %s, %v", string(bc), err)
+	}
+	pool := xdsclient.NewPool(config)
+	client, close, err := pool.NewClientForTesting(xdsclient.OptionsForTesting{
+		Name: t.Name(),
+	})
+	if err != nil {
+		t.Fatalf("Failed to create xDS client: %v", err)
+	}
+	defer close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	t.Run("Multiple_ResourceType_Implementations", func(t *testing.T) {
+		const routeConfigName = "route-config-name"
+		watcher := xdstestutils.NewTestResourceWatcher()
+		client.WatchResource(routeConfigResourceType, routeConfigName, watcher)
+
+		sCtx, sCancel := context.WithTimeout(ctx, defaultTestShortTimeout)
+		defer sCancel()
+		select {
+		case <-sCtx.Done():
+		case <-watcher.UpdateCh:
+			t.Fatal("Unexpected resource update")
+		case <-watcher.ErrorCh:
+			t.Fatal("Unexpected resource error")
+		case <-watcher.ResourceDoesNotExistCh:
+			t.Fatal("Unexpected resource does not exist")
+		}
+
+		client.WatchResource(testRouteConfigResourceType{}, routeConfigName, watcher)
+		select {
+		case <-ctx.Done():
+			t.Fatal("Timeout when waiting for error callback to be invoked")
+		case err := <-watcher.ErrorCh:
+			if err == nil || !strings.Contains(err.Error(), nodeID) {
+				t.Fatalf("Unexpected error: %v, want error with node ID: %q", err, nodeID)
+			}
+		}
+	})
+
+	t.Run("Missing_Authority", func(t *testing.T) {
+		const routeConfigName = "xdstp://nonexistant-authority/envoy.config.route.v3.RouteConfiguration/route-config-name"
+		watcher := xdstestutils.NewTestResourceWatcher()
+		client.WatchResource(routeConfigResourceType, routeConfigName, watcher)
+
+		select {
+		case <-ctx.Done():
+			t.Fatal("Timeout when waiting for error callback to be invoked")
+		case err := <-watcher.ErrorCh:
+			if err == nil || !strings.Contains(err.Error(), nodeID) {
+				t.Fatalf("Unexpected error: %v, want error with node ID: %q", err, nodeID)
+			}
+		}
+	})
+}
+
+// Tests that the errors returned by the xDS client when watching a resource
+// contain the node ID when channel creation to the management server fails.
+func (s) TestWatchErrorsContainNodeID_ChannelCreationFailure(t *testing.T) {
+	mgmtServer := e2e.StartManagementServer(t, e2e.ManagementServerOptions{})
+
+	// Create bootstrap configuration pointing to the above management server.
+	nodeID := uuid.New().String()
+	bc := e2e.DefaultBootstrapContents(t, nodeID, mgmtServer.Address)
+
+	// Create an xDS client with the above bootstrap contents.
+	config, err := bootstrap.NewConfigFromContents(bc)
+	if err != nil {
+		t.Fatalf("Failed to parse bootstrap contents: %s, %v", string(bc), err)
+	}
+	pool := xdsclient.NewPool(config)
+	client, close, err := pool.NewClientForTesting(xdsclient.OptionsForTesting{
+		Name: t.Name(),
+	})
+	if err != nil {
+		t.Fatalf("Failed to create xDS client: %v", err)
+	}
+	defer close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	// Override the xDS channel dialer with one that always fails.
+	origDialer := xdsclientinternal.GRPCNewClient
+	xdsclientinternal.GRPCNewClient = func(target string, opts ...grpc.DialOption) (*grpc.ClientConn, error) {
+		return nil, fmt.Errorf("failed to create channel")
+	}
+	defer func() { xdsclientinternal.GRPCNewClient = origDialer }()
+
+	const routeConfigName = "route-config-name"
+	watcher := xdstestutils.NewTestResourceWatcher()
+	client.WatchResource(routeConfigResourceType, routeConfigName, watcher)
+
+	select {
+	case <-ctx.Done():
+		t.Fatal("Timeout when waiting for error callback to be invoked")
+	case err := <-watcher.ErrorCh:
+		if err == nil || !strings.Contains(err.Error(), nodeID) {
+			t.Fatalf("Unexpected error: %v, want error with node ID: %q", err, nodeID)
+		}
+	}
+}