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Provide a truly lazy restmapper
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Rework WithLazyDiscovery to use DeferredDiscoveryRESTMapper that
will lazily query the provided client for discovery information
to do REST mappings.
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@Fedosin
Fedosin committed Jan 2, 2023
1 parent 3c4deba commit 611684e
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Showing 2 changed files with 28 additions and 79 deletions.
85 changes: 28 additions & 57 deletions pkg/client/apiutil/dynamicrestmapper.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,12 +18,12 @@ package apiutil

import (
"sync"
"sync/atomic"

"golang.org/x/time/rate"
"k8s.io/apimachinery/pkg/api/meta"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/client-go/discovery"
"k8s.io/client-go/discovery/cached/memory"
"k8s.io/client-go/rest"
"k8s.io/client-go/restmapper"
)
Expand All @@ -37,9 +37,6 @@ type dynamicRESTMapper struct {
newMapper func() (meta.RESTMapper, error)

lazy bool
// Used for lazy init.
inited uint32
initMtx sync.Mutex
}

// DynamicRESTMapperOption is a functional option on the dynamicRESTMapper.
Expand Down Expand Up @@ -76,30 +73,43 @@ func WithCustomMapper(newMapper func() (meta.RESTMapper, error)) DynamicRESTMapp
// RESTMapper dynamically discovers resource types at runtime. opts
// configure the RESTMapper.
func NewDynamicRESTMapper(cfg *rest.Config, opts ...DynamicRESTMapperOption) (meta.RESTMapper, error) {
client, err := discovery.NewDiscoveryClientForConfig(cfg)
if err != nil {
return nil, err
}
drm := &dynamicRESTMapper{
limiter: rate.NewLimiter(rate.Limit(defaultRefillRate), defaultLimitSize),
newMapper: func() (meta.RESTMapper, error) {
groupResources, err := restmapper.GetAPIGroupResources(client)
if err != nil {
return nil, err
}
return restmapper.NewDiscoveryRESTMapper(groupResources), nil
},
}
for _, opt := range opts {
if err = opt(drm); err != nil {
if err := opt(drm); err != nil {
return nil, err
}
}
if !drm.lazy {
if err := drm.setStaticMapper(); err != nil {

if drm.newMapper == nil {
// If custom mapper is not set, we wse NewDeferredDiscoveryRESTMapper for lazy loading
// or standard NewDiscoveryRESTMapper for other cases.
client, err := discovery.NewDiscoveryClientForConfig(cfg)
if err != nil {
return nil, err
}

if !drm.lazy {
drm.newMapper = func() (meta.RESTMapper, error) {
groupResources, err := restmapper.GetAPIGroupResources(client)
if err != nil {
return nil, err
}

return restmapper.NewDiscoveryRESTMapper(groupResources), nil
}
} else {
drm.newMapper = func() (meta.RESTMapper, error) {
return restmapper.NewDeferredDiscoveryRESTMapper(memory.NewMemCacheClient(client)), nil
}
}
}

if err := drm.setStaticMapper(); err != nil {
return nil, err
}

return drm, nil
}

Expand All @@ -124,23 +134,6 @@ func (drm *dynamicRESTMapper) setStaticMapper() error {
return nil
}

// init initializes drm only once if drm is lazy.
func (drm *dynamicRESTMapper) init() (err error) {
// skip init if drm is not lazy or has initialized
if !drm.lazy || atomic.LoadUint32(&drm.inited) != 0 {
return nil
}

drm.initMtx.Lock()
defer drm.initMtx.Unlock()
if drm.inited == 0 {
if err = drm.setStaticMapper(); err == nil {
atomic.StoreUint32(&drm.inited, 1)
}
}
return err
}

// checkAndReload attempts to call the given callback, which is assumed to be dependent
// on the data in the restmapper.
//
Expand Down Expand Up @@ -198,9 +191,6 @@ func (drm *dynamicRESTMapper) checkAndReload(checkNeedsReload func() error) erro
// TODO: wrap reload errors on NoKindMatchError with go 1.13 errors.

func (drm *dynamicRESTMapper) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
if err := drm.init(); err != nil {
return schema.GroupVersionKind{}, err
}
var gvk schema.GroupVersionKind
err := drm.checkAndReload(func() error {
var err error
Expand All @@ -211,9 +201,6 @@ 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
}
var gvks []schema.GroupVersionKind
err := drm.checkAndReload(func() error {
var err error
Expand All @@ -224,10 +211,6 @@ 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
}

var gvr schema.GroupVersionResource
err := drm.checkAndReload(func() error {
var err error
Expand All @@ -238,9 +221,6 @@ 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
}
var gvrs []schema.GroupVersionResource
err := drm.checkAndReload(func() error {
var err error
Expand All @@ -251,9 +231,6 @@ 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
}
var mapping *meta.RESTMapping
err := drm.checkAndReload(func() error {
var err error
Expand All @@ -264,9 +241,6 @@ 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
}
var mappings []*meta.RESTMapping
err := drm.checkAndReload(func() error {
var err error
Expand All @@ -277,9 +251,6 @@ 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
}
var singular string
err := drm.checkAndReload(func() error {
var err error
Expand Down
22 changes: 0 additions & 22 deletions pkg/client/apiutil/dynamicrestmapper_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,6 @@ limitations under the License.
package apiutil

import (
"fmt"
"time"

. "github.com/onsi/ginkgo/v2"
Expand Down Expand Up @@ -145,27 +144,6 @@ var _ = Describe("Dynamic REST Mapper", func() {
By("ensuring that it was only refreshed once")
Expect(count).To(Equal(1))
})

It("should lazily initialize if the lazy option is used", func() {
var err error
var failedOnce bool
mockErr := fmt.Errorf("mock failed once")
mapper, err = NewDynamicRESTMapper(cfg, WithLazyDiscovery, WithCustomMapper(func() (meta.RESTMapper, error) {
// Make newMapper fail once
if !failedOnce {
failedOnce = true
return nil, mockErr
}
baseMapper := meta.NewDefaultRESTMapper(nil)
addToMapper(baseMapper)
return baseMapper, nil
}))
Expect(err).NotTo(HaveOccurred())
Expect(mapper.(*dynamicRESTMapper).staticMapper).To(BeNil())

Expect(callWithTarget()).To(MatchError(mockErr))
Expect(callWithTarget()).To(Succeed())
})
}

Describe("KindFor", func() {
Expand Down

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