lister.go

Documentation: k8s.io/client-go/metadata/metadatalister

     1  /*
     2  Copyright 2018 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package metadatalister
    18  
    19  import (
    20  	"k8s.io/apimachinery/pkg/api/errors"
    21  	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    22  	"k8s.io/apimachinery/pkg/labels"
    23  	"k8s.io/apimachinery/pkg/runtime/schema"
    24  	"k8s.io/client-go/tools/cache"
    25  )
    26  
    27  var _ Lister = &metadataLister{}
    28  var _ NamespaceLister = &metadataNamespaceLister{}
    29  
    30  // metadataLister implements the Lister interface.
    31  type metadataLister struct {
    32  	indexer cache.Indexer
    33  	gvr     schema.GroupVersionResource
    34  }
    35  
    36  // New returns a new Lister.
    37  func New(indexer cache.Indexer, gvr schema.GroupVersionResource) Lister {
    38  	return &metadataLister{indexer: indexer, gvr: gvr}
    39  }
    40  
    41  // List lists all resources in the indexer.
    42  func (l *metadataLister) List(selector labels.Selector) (ret []*metav1.PartialObjectMetadata, err error) {
    43  	err = cache.ListAll(l.indexer, selector, func(m interface{}) {
    44  		ret = append(ret, m.(*metav1.PartialObjectMetadata))
    45  	})
    46  	return ret, err
    47  }
    48  
    49  // Get retrieves a resource from the indexer with the given name
    50  func (l *metadataLister) Get(name string) (*metav1.PartialObjectMetadata, error) {
    51  	obj, exists, err := l.indexer.GetByKey(name)
    52  	if err != nil {
    53  		return nil, err
    54  	}
    55  	if !exists {
    56  		return nil, errors.NewNotFound(l.gvr.GroupResource(), name)
    57  	}
    58  	return obj.(*metav1.PartialObjectMetadata), nil
    59  }
    60  
    61  // Namespace returns an object that can list and get resources from a given namespace.
    62  func (l *metadataLister) Namespace(namespace string) NamespaceLister {
    63  	return &metadataNamespaceLister{indexer: l.indexer, namespace: namespace, gvr: l.gvr}
    64  }
    65  
    66  // metadataNamespaceLister implements the NamespaceLister interface.
    67  type metadataNamespaceLister struct {
    68  	indexer   cache.Indexer
    69  	namespace string
    70  	gvr       schema.GroupVersionResource
    71  }
    72  
    73  // List lists all resources in the indexer for a given namespace.
    74  func (l *metadataNamespaceLister) List(selector labels.Selector) (ret []*metav1.PartialObjectMetadata, err error) {
    75  	err = cache.ListAllByNamespace(l.indexer, l.namespace, selector, func(m interface{}) {
    76  		ret = append(ret, m.(*metav1.PartialObjectMetadata))
    77  	})
    78  	return ret, err
    79  }
    80  
    81  // Get retrieves a resource from the indexer for a given namespace and name.
    82  func (l *metadataNamespaceLister) Get(name string) (*metav1.PartialObjectMetadata, error) {
    83  	obj, exists, err := l.indexer.GetByKey(l.namespace + "/" + name)
    84  	if err != nil {
    85  		return nil, err
    86  	}
    87  	if !exists {
    88  		return nil, errors.NewNotFound(l.gvr.GroupResource(), name)
    89  	}
    90  	return obj.(*metav1.PartialObjectMetadata), nil
    91  }
    92
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