/
client.go
104 lines (89 loc) · 2.95 KB
/
client.go
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package dynamicclient
import (
"sync"
"time"
"github.com/pkg/errors"
"k8s.io/apimachinery/pkg/api/meta"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/client-go/discovery/cached"
"k8s.io/client-go/dynamic"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
"k8s.io/client-go/restmapper"
)
type resourceClientFactory struct {
dynamicClient dynamic.Interface
restMapper *restmapper.DeferredDiscoveryRESTMapper
}
var (
// this stores the singleton in a package local
singletonFactory *resourceClientFactory
once sync.Once
)
// Private constructor for once.Do
func newSingletonFactory(config *rest.Config) func() {
return func() {
cachedDiscoveryClient := cached.NewMemCacheClient(kubernetes.NewForConfigOrDie(config).Discovery())
restMapper := restmapper.NewDeferredDiscoveryRESTMapper(cachedDiscoveryClient)
restMapper.Reset()
dynamicClient, err := dynamic.NewForConfig(config)
if err != nil {
panic(err)
}
singletonFactory = &resourceClientFactory{
dynamicClient: dynamicClient,
restMapper: restMapper,
}
singletonFactory.runBackgroundCacheReset(1 * time.Minute)
}
}
// New returns the resource client using a singleton factory
func New(config *rest.Config, gvk schema.GroupVersionKind, namespace string) (dynamic.ResourceInterface, error) {
once.Do(newSingletonFactory(config))
return singletonFactory.getResourceClient(gvk, namespace)
}
// getResourceClient returns the dynamic client for the resource specified by the gvk.
func (c *resourceClientFactory) getResourceClient(gvk schema.GroupVersionKind, namespace string) (dynamic.ResourceInterface, error) {
var (
gvr *schema.GroupVersionResource
namespaced bool
err error
)
gvr, namespaced, err = gvkToGVR(gvk, c.restMapper)
if meta.IsNoMatchError(err) {
// refresh the restMapperCache and try once more.
c.restMapper.Reset()
gvr, namespaced, err = gvkToGVR(gvk, c.restMapper)
}
if err != nil {
return nil, errors.Wrapf(err, "failed to get resource type")
}
// sometimes manifests of non-namespaced resources
// might have namespace set.
// preventing such cases.
ns := namespace
if !namespaced {
ns = ""
}
return c.dynamicClient.Resource(*gvr).Namespace(ns), nil
}
func gvkToGVR(gvk schema.GroupVersionKind, restMapper *restmapper.DeferredDiscoveryRESTMapper) (*schema.GroupVersionResource, bool, error) {
mapping, err := restMapper.RESTMapping(gvk.GroupKind(), gvk.Version)
if meta.IsNoMatchError(err) {
return nil, false, err
}
if err != nil {
return nil, false, errors.Wrapf(err, "failed to get the resource REST mapping for GroupVersionKind(%s)", gvk.String())
}
return &mapping.Resource, mapping.Scope.Name() == meta.RESTScopeNameNamespace, nil
}
// runBackgroundCacheReset - Starts the rest mapper cache reseting
// at a duration given.
func (c *resourceClientFactory) runBackgroundCacheReset(duration time.Duration) {
ticker := time.NewTicker(duration)
go func() {
for range ticker.C {
c.restMapper.Reset()
}
}()
}