karmada/pkg/util/restmapper/restmapper.go

145 lines
4.7 KiB
Go

package restmapper
import (
"net/http"
"sync"
"k8s.io/apimachinery/pkg/api/meta"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/client-go/discovery"
"k8s.io/client-go/rest"
"k8s.io/client-go/restmapper"
)
// GetGroupVersionResource is a helper to map GVK(schema.GroupVersionKind) to GVR(schema.GroupVersionResource).
func GetGroupVersionResource(restMapper meta.RESTMapper, gvk schema.GroupVersionKind) (schema.GroupVersionResource, error) {
restMapping, err := restMapper.RESTMapping(gvk.GroupKind(), gvk.Version)
if err != nil {
return schema.GroupVersionResource{}, err
}
return restMapping.Resource, nil
}
// cachedRESTMapper caches the previous result to accelerate subsequent queries.
// Note: now the acceleration applies only to RESTMapping() which is heavily used by Karmada.
type cachedRESTMapper struct {
restMapper meta.RESTMapper
discoveryClient discovery.DiscoveryInterface
gvkToGVR sync.Map
// mu is used to provide thread-safe mapper reloading.
mu sync.RWMutex
}
func (g *cachedRESTMapper) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
return g.getMapper().KindFor(resource)
}
func (g *cachedRESTMapper) KindsFor(resource schema.GroupVersionResource) ([]schema.GroupVersionKind, error) {
return g.getMapper().KindsFor(resource)
}
func (g *cachedRESTMapper) ResourceFor(input schema.GroupVersionResource) (schema.GroupVersionResource, error) {
return g.getMapper().ResourceFor(input)
}
func (g *cachedRESTMapper) ResourcesFor(input schema.GroupVersionResource) ([]schema.GroupVersionResource, error) {
return g.getMapper().ResourcesFor(input)
}
func (g *cachedRESTMapper) RESTMappings(gk schema.GroupKind, versions ...string) ([]*meta.RESTMapping, error) {
return g.getMapper().RESTMappings(gk, versions...)
}
func (g *cachedRESTMapper) ResourceSingularizer(resource string) (singular string, err error) {
return g.getMapper().ResourceSingularizer(resource)
}
func (g *cachedRESTMapper) RESTMapping(gk schema.GroupKind, versions ...string) (*meta.RESTMapping, error) {
// in case of multi-versions or no versions, cachedRESTMapper don't know which is the preferred version,
// so just bypass the cache and consult the underlying mapper.
if len(versions) != 1 {
return g.getMapper().RESTMapping(gk, versions...)
}
gvk := gk.WithVersion(versions[0])
value, ok := g.gvkToGVR.Load(gvk)
if ok { // hit cache, just return
return value.(*meta.RESTMapping), nil
}
// consult underlying mapper and then update cache
restMapping, err := g.getMapper().RESTMapping(gk, versions...)
if meta.IsNoMatchError(err) {
// hit here means a resource might be missing from the current rest mapper,
// probably because a new resource(CRD) has been added, we have to reload
// resource and rebuild the rest mapper.
var groupResources []*restmapper.APIGroupResources
groupResources, err = restmapper.GetAPIGroupResources(g.discoveryClient)
if err != nil {
return nil, err
}
newMapper := restmapper.NewDiscoveryRESTMapper(groupResources)
restMapping, err = newMapper.RESTMapping(gk, versions...)
if err == nil {
// hit here means after reloading, the new rest mapper can recognize
// the resource, we have to replace the mapper and clear cache.
g.mu.Lock()
g.restMapper = newMapper
g.mu.Unlock()
g.gvkToGVR.Range(func(key, value any) bool {
g.gvkToGVR.Delete(key)
return true
})
}
}
if err != nil {
return restMapping, err
}
g.gvkToGVR.Store(gvk, restMapping)
return restMapping, nil
}
func (g *cachedRESTMapper) getMapper() meta.RESTMapper {
g.mu.RLock()
defer g.mu.RUnlock()
return g.restMapper
}
// NewCachedRESTMapper builds a cachedRESTMapper with a customized underlyingMapper.
// If underlyingMapper is nil, defaults to DiscoveryRESTMapper.
func NewCachedRESTMapper(cfg *rest.Config, underlyingMapper meta.RESTMapper) (meta.RESTMapper, error) {
cachedMapper := cachedRESTMapper{}
// short path, build with customized underlying mapper.
if underlyingMapper != nil {
cachedMapper.restMapper = underlyingMapper
return &cachedMapper, nil
}
client, err := discovery.NewDiscoveryClientForConfig(cfg)
if err != nil {
return nil, err
}
// loading current resources for building a base rest mapper.
groupResources, err := restmapper.GetAPIGroupResources(client)
if err != nil {
return nil, err
}
cachedMapper.restMapper = restmapper.NewDiscoveryRESTMapper(groupResources)
cachedMapper.discoveryClient = client
return &cachedMapper, nil
}
// MapperProvider is a wrapper of cachedRESTMapper which is typically used
// to generate customized RESTMapper for controller-runtime framework.
func MapperProvider(c *rest.Config, _ *http.Client) (meta.RESTMapper, error) {
return NewCachedRESTMapper(c, nil)
}