github.com/openebs/node-disk-manager@v1.9.1-0.20230225014141-4531f06ffa1e/db/kubernetes/filter.go (about)

     1  /*
     2  Copyright 2019 The OpenEBS 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 kubernetes
    18  
    19  import (
    20  	"errors"
    21  	"github.com/openebs/node-disk-manager/blockdevice"
    22  	"k8s.io/apimachinery/pkg/labels"
    23  	"k8s.io/apimachinery/pkg/selection"
    24  	"sigs.k8s.io/controller-runtime/pkg/client"
    25  )
    26  
    27  // GenerateLabelFilter is used to generate a label filter that can be used
    28  // while listing resources
    29  func GenerateLabelFilter(key, value string) (interface{}, error) {
    30  
    31  	// if key or value is empty, filter will be empty string
    32  	if len(key) == 0 ||
    33  		len(value) == 0 {
    34  		return nil, errors.New("key/value is empty for label filter")
    35  	}
    36  
    37  	filterKey := getFilterKey(key)
    38  
    39  	label := client.MatchingLabels{filterKey: value}
    40  
    41  	return label, nil
    42  }
    43  
    44  // GenerateLabelFilterWithOp creates a label filter with the given operator
    45  // between key and value
    46  func GenerateLabelFilterWithOp(key, op, value string) (interface{}, error) {
    47  	if len(key) == 0 ||
    48  		len(value) == 0 ||
    49  		len(op) == 0 {
    50  		return nil, errors.New("key/operator/value is empty for filter")
    51  	}
    52  	operator := selection.Operator(op)
    53  	sel := labels.NewSelector()
    54  	req, err := labels.NewRequirement(key, operator, []string{value})
    55  	if err != nil {
    56  		return nil, errors.New("failed to create new requirement in label filter")
    57  	}
    58  	sel.Add(*req)
    59  
    60  	return client.MatchingLabelsSelector{Selector: sel}, nil
    61  }
    62  
    63  func getFilterKey(key string) string {
    64  	switch key {
    65  	// if key is hostname, it should be changed to kubernetes hostname label
    66  	case blockdevice.HostName:
    67  		return KubernetesHostNameLabel
    68  	}
    69  	return key
    70  }