correct laziness

Author: estroz

pkg/client/apiutil/dynamicrestmapper.go

@@ -17,6 +17,7 @@ limitations under the License.
 package apiutil
 
 import (
+	"sync"
 	"time"
 
 	"golang.org/x/time/rate"
@@ -57,7 +58,10 @@ type dynamicRESTMapper struct {
 	client       discovery.DiscoveryInterface
 	staticMapper meta.RESTMapper
 	limiter      *dynamicLimiter
-	lazy         bool
+
+	lazy bool
+	// Used for lazy init.
+	initOnce sync.Once
 }
 
 // WithLimiter sets the RESTMapper's underlying limiter to lim.
@@ -121,6 +125,16 @@ func (drm *dynamicRESTMapper) setStaticMapper() error {
 	return nil
 }
 
+// init initializes drm only once if drm is lazy.
+func (drm *dynamicRESTMapper) init() (err error) {
+	drm.initOnce.Do(func() {
+		if drm.lazy {
+			err = drm.setStaticMapper()
+		}
+	})
+	return err
+}
+
 // reload reloads the static RESTMapper, and will return an error only
 // if a rate limit has been hit.
 func (drm *dynamicRESTMapper) reload() error {
@@ -134,6 +148,9 @@ func (drm *dynamicRESTMapper) reload() error {
 }
 
 func (drm *dynamicRESTMapper) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
+	if err := drm.init(); err != nil {
+		return schema.GroupVersionKind{}, err
+	}
 	gvk, err := drm.staticMapper.KindFor(resource)
 	if xerrors.Is(err, &meta.NoKindMatchError{}) {
 		if rerr := drm.reload(); rerr != nil {
@@ -145,6 +162,9 @@ func (drm *dynamicRESTMapper) KindFor(resource schema.GroupVersionResource) (sch
 }
 
 func (drm *dynamicRESTMapper) KindsFor(resource schema.GroupVersionResource) ([]schema.GroupVersionKind, error) {
+	if err := drm.init(); err != nil {
+		return nil, err
+	}
 	gvks, err := drm.staticMapper.KindsFor(resource)
 	if xerrors.Is(err, &meta.NoKindMatchError{}) {
 		if rerr := drm.reload(); rerr != nil {
@@ -156,6 +176,9 @@ func (drm *dynamicRESTMapper) KindsFor(resource schema.GroupVersionResource) ([]
 }
 
 func (drm *dynamicRESTMapper) ResourceFor(input schema.GroupVersionResource) (schema.GroupVersionResource, error) {
+	if err := drm.init(); err != nil {
+		return schema.GroupVersionResource{}, err
+	}
 	gvr, err := drm.staticMapper.ResourceFor(input)
 	if xerrors.Is(err, &meta.NoKindMatchError{}) {
 		if rerr := drm.reload(); rerr != nil {
@@ -167,6 +190,9 @@ func (drm *dynamicRESTMapper) ResourceFor(input schema.GroupVersionResource) (sc
 }
 
 func (drm *dynamicRESTMapper) ResourcesFor(input schema.GroupVersionResource) ([]schema.GroupVersionResource, error) {
+	if err := drm.init(); err != nil {
+		return nil, err
+	}
 	gvrs, err := drm.staticMapper.ResourcesFor(input)
 	if xerrors.Is(err, &meta.NoKindMatchError{}) {
 		if rerr := drm.reload(); rerr != nil {
@@ -178,6 +204,9 @@ func (drm *dynamicRESTMapper) ResourcesFor(input schema.GroupVersionResource) ([
 }
 
 func (drm *dynamicRESTMapper) RESTMapping(gk schema.GroupKind, versions ...string) (*meta.RESTMapping, error) {
+	if err := drm.init(); err != nil {
+		return nil, err
+	}
 	mapping, err := drm.staticMapper.RESTMapping(gk, versions...)
 	if xerrors.Is(err, &meta.NoKindMatchError{}) {
 		if rerr := drm.reload(); rerr != nil {
@@ -189,6 +218,9 @@ func (drm *dynamicRESTMapper) RESTMapping(gk schema.GroupKind, versions ...strin
 }
 
 func (drm *dynamicRESTMapper) RESTMappings(gk schema.GroupKind, versions ...string) ([]*meta.RESTMapping, error) {
+	if err := drm.init(); err != nil {
+		return nil, err
+	}
 	mappings, err := drm.staticMapper.RESTMappings(gk, versions...)
 	if xerrors.Is(err, &meta.NoKindMatchError{}) {
 		if rerr := drm.reload(); rerr != nil {
@@ -200,6 +232,9 @@ func (drm *dynamicRESTMapper) RESTMappings(gk schema.GroupKind, versions ...stri
 }
 
 func (drm *dynamicRESTMapper) ResourceSingularizer(resource string) (string, error) {
+	if err := drm.init(); err != nil {
+		return "", err
+	}
 	singular, err := drm.staticMapper.ResourceSingularizer(resource)
 	if xerrors.Is(err, &meta.NoKindMatchError{}) {
 		if rerr := drm.reload(); rerr != nil {