Convert dynamicdesktopwatcher to use genericwatcher

lib/services/readonly/readonly.go

@@ -432,3 +432,22 @@ type Server interface {
 	// GetAWSAccountID returns the AWS Account ID if this node comes from an EC2 instance.
 	GetAWSAccountID() string
 }
+
+// DynamicWindowsDesktop represents a Windows desktop host that is automatically discovered by Windows Desktop Service.
+type DynamicWindowsDesktop interface {
+	// ResourceWithLabels provides common resource methods.
+	ResourceWithLabels
+	// GetAddr returns the network address of this host.
+	GetAddr() string
+	// GetDomain returns the ActiveDirectory domain of this host.
+	GetDomain() string
+	// NonAD checks whether this is a standalone host that
+	// is not joined to an Active Directory domain.
+	NonAD() bool
+	// GetScreenSize returns the desired size of the screen to use for sessions
+	// to this host. Returns (0, 0) if no screen size is set, which means to
+	// use the size passed by the client over TDP.
+	GetScreenSize() (width, height uint32)
+	// Copy returns a copy of this dynamic Windows desktop
+	Copy() *types.DynamicWindowsDesktopV1
+}

lib/services/watcher.go

@@ -537,6 +537,54 @@ func NewKubeClusterWatcher(ctx context.Context, cfg KubeClusterWatcherConfig) (*
 	return w, trace.Wrap(err)
 }
 
+type DynamicWindowsDesktopGetter interface {
+	ListDynamicWindowsDesktops(ctx context.Context, pageSize int, pageToken string) ([]types.DynamicWindowsDesktop, string, error)
+}
+
+// DynamicWindowsDesktopWatcherConfig is a DynamicWindowsDesktopWatcher configuration.
+type DynamicWindowsDesktopWatcherConfig struct {
+	// DynamicWindowsDesktopGetter is responsible for fetching DynamicWindowsDesktop resources.
+	DynamicWindowsDesktopGetter
+	// DynamicWindowsDesktopsC receives up-to-date list of all DynamicWindowsDesktop resources.
+	DynamicWindowsDesktopsC chan []types.DynamicWindowsDesktop
+	// ResourceWatcherConfig is the resource watcher configuration.
+	ResourceWatcherConfig
+}
+
+// NewDynamicWindowsDesktopWatcher returns a new instance of DynamicWindowsDesktopWatcher.
+func NewDynamicWindowsDesktopWatcher(ctx context.Context, cfg DynamicWindowsDesktopWatcherConfig) (*GenericWatcher[types.DynamicWindowsDesktop, readonly.DynamicWindowsDesktop], error) {
+	if cfg.DynamicWindowsDesktopGetter == nil {
+		return nil, trace.BadParameter("KubernetesClusterGetter must be provided")
+	}
+
+	w, err := NewGenericResourceWatcher(ctx, GenericWatcherConfig[types.DynamicWindowsDesktop, readonly.DynamicWindowsDesktop]{
+		ResourceWatcherConfig: cfg.ResourceWatcherConfig,
+		ResourceKind:          types.KindDynamicWindowsDesktop,
+		ResourceGetter: func(ctx context.Context) ([]types.DynamicWindowsDesktop, error) {
+			var desktops []types.DynamicWindowsDesktop
+			next := ""
+			for {
+				d, token, err := cfg.DynamicWindowsDesktopGetter.ListDynamicWindowsDesktops(ctx, defaults.MaxIterationLimit, next)
+				if err != nil {
+					return nil, err
+				}
+				desktops = append(desktops, d...)
+				if token == "" {
+					break
+				}
+				next = token
+			}
+			return desktops, nil
+		},
+		ResourceKey: types.DynamicWindowsDesktop.GetName,
+		ResourcesC:  cfg.DynamicWindowsDesktopsC,
+		CloneFunc: func(resource types.DynamicWindowsDesktop) types.DynamicWindowsDesktop {
+			return resource.Copy()
+		},
+	})
+	return w, trace.Wrap(err)
+}
+
 // GenericWatcherConfig is a generic resource watcher configuration.
 type GenericWatcherConfig[T any, R any] struct {
 	// ResourceGetter is used to directly fetch the current set of resources.

lib/srv/desktop/discovery.go

@@ -39,6 +39,7 @@ import (
 	"github.com/gravitational/teleport/lib/auth/windows"
 	"github.com/gravitational/teleport/lib/defaults"
 	"github.com/gravitational/teleport/lib/services"
+	"github.com/gravitational/teleport/lib/services/readonly"
 	"github.com/gravitational/teleport/lib/utils"
 )
 
@@ -310,7 +311,7 @@ func (s *WindowsService) ldapEntryToWindowsDesktop(
 
 // startDynamicReconciler starts resource watcher and reconciler that registers/unregisters Windows desktops
 // according to the up-to-date list of dynamic Windows desktops resources.
-func (s *WindowsService) startDynamicReconciler(ctx context.Context) (*services.DynamicWindowsDesktopWatcher, error) {
+func (s *WindowsService) startDynamicReconciler(ctx context.Context) (*services.GenericWatcher[types.DynamicWindowsDesktop, readonly.DynamicWindowsDesktop], error) {
 	if len(s.cfg.ResourceMatchers) == 0 {
 		s.cfg.Logger.DebugContext(ctx, "Not starting dynamic desktop resource watcher.")
 		return nil, nil
@@ -353,7 +354,7 @@ func (s *WindowsService) startDynamicReconciler(ctx context.Context) (*services.
 		defer watcher.Close()
 		for {
 			select {
-			case desktops := <-watcher.DynamicWindowsDesktopsC:
+			case desktops := <-watcher.ResourcesC:
 				newResources = make(map[string]types.WindowsDesktop)
 				for _, dynamicDesktop := range desktops {
 					desktop, err := s.toWindowsDesktop(dynamicDesktop)