istio

1
/*
2
Copyright 2017 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 k8sresourcelock
18

19
import (
20
	"context"
21
	"encoding/json"
22
	"errors"
23
	"fmt"
24

25
	v1 "k8s.io/api/core/v1"
26
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
27
	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
28
)
29

30
// TODO: This is almost a exact replica of Endpoints lock.
31
// going forwards as we self host more and more components
32
// and use ConfigMaps as the means to pass that configuration
33
// data we will likely move to deprecate the Endpoints lock.
34

35
type ConfigMapLock struct {
36
	// ConfigMapMeta should contain a Name and a Namespace of a
37
	// ConfigMapMeta object that the LeaderElector will attempt to lead.
38
	ConfigMapMeta metav1.ObjectMeta
39
	Client        corev1client.ConfigMapsGetter
40
	LockConfig    ResourceLockConfig
41
	cm            *v1.ConfigMap
42
}
43

44
// Get returns the election record from a ConfigMap Annotation
45
func (cml *ConfigMapLock) Get(ctx context.Context) (*LeaderElectionRecord, []byte, error) {
46
	var record LeaderElectionRecord
47
	var err error
48
	cml.cm, err = cml.Client.ConfigMaps(cml.ConfigMapMeta.Namespace).Get(ctx, cml.ConfigMapMeta.Name, metav1.GetOptions{})
49
	if err != nil {
50
		return nil, nil, err
51
	}
52
	if cml.cm.Annotations == nil {
53
		cml.cm.Annotations = make(map[string]string)
54
	}
55
	recordStr, found := cml.cm.Annotations[LeaderElectionRecordAnnotationKey]
56
	recordBytes := []byte(recordStr)
57
	if found {
58
		if err := json.Unmarshal(recordBytes, &record); err != nil {
59
			return nil, nil, err
60
		}
61
	}
62
	return &record, recordBytes, nil
63
}
64

65
// Create attempts to create a LeaderElectionRecord annotation
66
func (cml *ConfigMapLock) Create(ctx context.Context, ler LeaderElectionRecord) error {
67
	recordBytes, err := json.Marshal(ler)
68
	if err != nil {
69
		return err
70
	}
71
	cml.cm, err = cml.Client.ConfigMaps(cml.ConfigMapMeta.Namespace).Create(ctx, &v1.ConfigMap{
72
		ObjectMeta: metav1.ObjectMeta{
73
			Name:      cml.ConfigMapMeta.Name,
74
			Namespace: cml.ConfigMapMeta.Namespace,
75
			Annotations: map[string]string{
76
				LeaderElectionRecordAnnotationKey: string(recordBytes),
77
			},
78
		},
79
	}, metav1.CreateOptions{})
80
	return err
81
}
82

83
// Update will update an existing annotation on a given resource.
84
func (cml *ConfigMapLock) Update(ctx context.Context, ler LeaderElectionRecord) error {
85
	if cml.cm == nil {
86
		return errors.New("configmap not initialized, call get or create first")
87
	}
88
	recordBytes, err := json.Marshal(ler)
89
	if err != nil {
90
		return err
91
	}
92
	if cml.cm.Annotations == nil {
93
		cml.cm.Annotations = make(map[string]string)
94
	}
95
	cml.cm.Annotations[LeaderElectionRecordAnnotationKey] = string(recordBytes)
96
	cm, err := cml.Client.ConfigMaps(cml.ConfigMapMeta.Namespace).Update(ctx, cml.cm, metav1.UpdateOptions{})
97
	if err != nil {
98
		return err
99
	}
100
	cml.cm = cm
101
	return nil
102
}
103

104
// RecordEvent in leader election while adding meta-data
105
func (cml *ConfigMapLock) RecordEvent(s string) {
106
	if cml.LockConfig.EventRecorder == nil {
107
		return
108
	}
109
	events := fmt.Sprintf("%v %v", cml.LockConfig.Identity, s)
110
	cml.LockConfig.EventRecorder.Eventf(&v1.ConfigMap{ObjectMeta: cml.cm.ObjectMeta}, v1.EventTypeNormal, "LeaderElection", events)
111
}
112

113
// Describe is used to convert details on current resource lock
114
// into a string
115
func (cml *ConfigMapLock) Describe() string {
116
	return fmt.Sprintf("%v/%v", cml.ConfigMapMeta.Namespace, cml.ConfigMapMeta.Name)
117
}
118

119
// Identity returns the Identity of the lock
120
func (cml *ConfigMapLock) Identity() string {
121
	return cml.LockConfig.Identity
122
}
123

124
// Identity returns the Identity of the lock
125
func (cml *ConfigMapLock) Key() string {
126
	return cml.LockConfig.Key
127
}
128