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05ff4bb2fd
This adds a generic implementation of a lister, and uses it to replace the template code in generated listers. The corresponding templates are no longer used and are removed. Listers are reduced to their interfaces (non-namespaced and namespaced if appropriate), their specific structs, and their constructors. All method implementations are provided by the generic implementation. The dedicated interface is preserved so that each lister can have its own set of methods (e.g. the method returning the namespaced lister if appropriate), and the dedicated struct is preserved to allow expansions to be defined where necessary. The external interface is unchanged and doesn't expose generics. Signed-off-by: Stephen Kitt <skitt@redhat.com> Kubernetes-commit: 2e9adcd14aae27394238291fa08fb603bf2f3e77
73 lines
2.6 KiB
Go
73 lines
2.6 KiB
Go
/*
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Copyright 2023 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package listers
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import (
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"k8s.io/apimachinery/pkg/api/errors"
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"k8s.io/apimachinery/pkg/labels"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/client-go/tools/cache"
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)
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// ResourceIndexer wraps an indexer, resource, and optional namespace for a given type.
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// This is intended for use by listers (generated by lister-gen) only.
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type ResourceIndexer[T runtime.Object] struct {
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indexer cache.Indexer
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resource schema.GroupResource
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namespace string // empty for non-namespaced types
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}
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// New returns a new instance of a lister (resource indexer) wrapping the given indexer and resource for the specified type.
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// This is intended for use by listers (generated by lister-gen) only.
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func New[T runtime.Object](indexer cache.Indexer, resource schema.GroupResource) ResourceIndexer[T] {
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return ResourceIndexer[T]{indexer: indexer, resource: resource}
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}
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// NewNamespaced returns a new instance of a namespaced lister (resource indexer) wrapping the given parent and namespace for the specified type.
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// This is intended for use by listers (generated by lister-gen) only.
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func NewNamespaced[T runtime.Object](parent ResourceIndexer[T], namespace string) ResourceIndexer[T] {
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return ResourceIndexer[T]{indexer: parent.indexer, resource: parent.resource, namespace: namespace}
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}
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// List lists all resources in the indexer matching the given selector.
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func (l ResourceIndexer[T]) List(selector labels.Selector) (ret []T, err error) {
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// ListAllByNamespace reverts to ListAll on empty namespaces
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err = cache.ListAllByNamespace(l.indexer, l.namespace, selector, func(m interface{}) {
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ret = append(ret, m.(T))
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})
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return ret, err
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}
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// Get retrieves the resource from the index for a given name.
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func (l ResourceIndexer[T]) Get(name string) (T, error) {
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var key string
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if l.namespace == "" {
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key = name
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} else {
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key = l.namespace + "/" + name
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}
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obj, exists, err := l.indexer.GetByKey(key)
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if err != nil {
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return *new(T), err
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}
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if !exists {
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return *new(T), errors.NewNotFound(l.resource, name)
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}
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return obj.(T), nil
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}
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