1.2.2 创建 APIExtensions Server
创建完通用 APIServer 后继续创建 APIExtensions Server。
func (c completedConfig) New(delegationTarget genericapiserver.DelegationTarget) (*CustomResourceDefinitions, error) {
genericServer, err := c.GenericConfig.New("apiextensions-apiserver", delegationTarget)
s := &CustomResourceDefinitions{
GenericAPIServer: genericServer,
}
// 存储建立 REST API 到资源实体的信息
apiGroupInfo := genericapiserver.NewDefaultAPIGroupInfo(apiextensions.GroupName, Scheme, metav1.ParameterCodec, Codecs)
// 资源实体
storage := map[string]rest.Storage{}
// customresourcedefinitions
if resource := "customresourcedefinitions"; apiResourceConfig.ResourceEnabled(v1.SchemeGroupVersion.WithResource(resource)) {
// 创建资源实体
customResourceDefinitionStorage, err := customresourcedefinition.NewREST(Scheme, c.GenericConfig.RESTOptionsGetter)
if err != nil {
return nil, err
}
storage[resource] = customResourceDefinitionStorage
storage[resource+"/status"] = customresourcedefinition.NewStatusREST(Scheme, customResourceDefinitionStorage)
}
if len(storage) > 0 {
apiGroupInfo.VersionedResourcesStorageMap[v1.SchemeGroupVersion.Version] = storage
}
if err := s.GenericAPIServer.InstallAPIGroup(&apiGroupInfo); err != nil {
return nil, err
}
APIGroupInfo 对象用于描述资源组信息，storage 存储资源到资源实体的对应关系。
资源实体，通过 NewREST() 函数创建。
kubernetes/vendor/k8s.io/apiextensions-apiserver/pkg/registry/customresourcedefinition/etcd.go
package customresourcedefinition
// NewREST returns a RESTStorage object that will work against API services.
func NewREST(scheme runtime.Scheme, optsGetter generic.RESTOptionsGetter) (REST, error) {
strategy := NewStrategy(scheme)
store := &genericregistry.Store{
NewFunc: func() runtime.Object { return &apiextensions.CustomResourceDefinition{} },
NewListFunc: func() runtime.Object { return &apiextensions.CustomResourceDefinitionList{} },
PredicateFunc: MatchCustomResourceDefinition,
DefaultQualifiedResource: apiextensions.Resource("customresourcedefinitions"),
SingularQualifiedResource: apiextensions.Resource("customresourcedefinition"),
CreateStrategy: strategy,
UpdateStrategy: strategy,
DeleteStrategy: strategy,
ResetFieldsStrategy: strategy,
// TODO: define table converter that exposes more than name/creation timestamp
TableConvertor: rest.NewDefaultTableConvertor(apiextensions.Resource("customresourcedefinitions")),
}
options := &generic.StoreOptions{RESTOptions: optsGetter, AttrFunc: GetAttrs}
if err := store.CompleteWithOptions(options); err != nil {
return nil, err
}
return &REST{store}, nil
}
可以看到，资源实体是在资源包 customresourcedefinition 的 etcd.go 中创建的，创建的资源实体负责和 etcd 交互。
(关于 etcd 交互的部分先不讲，后续会专门介绍。)
创建完资源实体后，通过 apiGroupInfo.VersionedResourcesStorageMap[v1.SchemeGroupVersion.Version] = storage 将资源实体存储到 apiGroupInfo。
继续调用 InstallAPIGroup(apiGroupInfo *APIGroupInfo) 安装 REST API。