forked from openshift/origin
/
admission.go
162 lines (136 loc) · 4.64 KB
/
admission.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
/*
Copyright 2017 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package lifecycle
import (
"fmt"
"io"
"time"
"github.com/golang/glog"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apiserver/pkg/admission"
kubeinformers "k8s.io/client-go/informers"
kubeclientset "k8s.io/client-go/kubernetes"
corev1 "k8s.io/client-go/listers/core/v1"
"k8s.io/client-go/pkg/api/v1"
scadmission "github.com/kubernetes-incubator/service-catalog/pkg/apiserver/admission"
)
const (
// PluginName is name of admission plug-in
PluginName = "KubernetesNamespaceLifecycle"
// how long to wait for a missing namespace before re-checking the cache (and then doing a live lookup)
// this accomplishes two things:
// 1. It allows a watch-fed cache time to observe a namespace creation event
// 2. It allows time for a namespace creation to distribute to members of a storage cluster,
// so the live lookup has a better chance of succeeding even if it isn't performed against the leader.
missingNamespaceWait = 50 * time.Millisecond
)
func init() {
admission.RegisterPlugin(PluginName, func(io.Reader) (admission.Interface, error) {
return NewLifecycle()
})
}
// lifecycle is an implementation of admission.Interface.
// It enforces life-cycle constraints around a Namespace depending on its Phase
type lifecycle struct {
*admission.Handler
client kubeclientset.Interface
namespaceLister corev1.NamespaceLister
}
type forceLiveLookupEntry struct {
expiry time.Time
}
var _ = scadmission.WantsKubeInformerFactory(&lifecycle{})
var _ = scadmission.WantsKubeClientSet(&lifecycle{})
func (l *lifecycle) Admit(a admission.Attributes) error {
// we need to wait for our caches to warm
if !l.WaitForReady() {
return admission.NewForbidden(a, fmt.Errorf("not yet ready to handle request"))
}
var (
exists bool
err error
)
namespace, err := l.namespaceLister.Get(a.GetNamespace())
if err != nil {
if !errors.IsNotFound(err) {
return errors.NewInternalError(err)
}
} else {
exists = true
}
// we only care about namespaced resources
if len(a.GetNamespace()) == 0 {
return nil
}
if !exists && a.GetOperation() == admission.Create {
// give the cache time to observe the namespace before rejecting a create.
// this helps when creating a namespace and immediately creating objects within it.
time.Sleep(missingNamespaceWait)
namespace, err = l.namespaceLister.Get(a.GetNamespace())
switch {
case errors.IsNotFound(err):
// no-op
case err != nil:
return errors.NewInternalError(err)
default:
exists = true
}
if exists {
glog.V(4).Infof("found %s in cache after waiting", a.GetNamespace())
}
}
// refuse to operate on non-existent namespaces
if !exists {
// as a last resort, make a call directly to storage
namespace, err = l.client.Core().Namespaces().Get(a.GetNamespace(), metav1.GetOptions{})
switch {
case errors.IsNotFound(err):
return err
case err != nil:
return errors.NewInternalError(err)
}
glog.V(4).Infof("found %s via storage lookup", a.GetNamespace())
}
// ensure that we're not trying to create objects in terminating namespaces
if a.GetOperation() == admission.Create {
if namespace.Status.Phase != v1.NamespaceTerminating {
return nil
}
return admission.NewForbidden(a, fmt.Errorf("unable to create new content in namespace %s because it is being terminated", a.GetNamespace()))
}
return nil
}
// NewLifecycle creates a new namespace lifecycle admission control handler
func NewLifecycle() (admission.Interface, error) {
return &lifecycle{
Handler: admission.NewHandler(admission.Create, admission.Update, admission.Delete),
}, nil
}
func (l *lifecycle) SetKubeInformerFactory(f kubeinformers.SharedInformerFactory) {
namespaceInformer := f.Core().V1().Namespaces()
l.namespaceLister = namespaceInformer.Lister()
l.SetReadyFunc(namespaceInformer.Informer().HasSynced)
}
func (l *lifecycle) SetKubeClientSet(client kubeclientset.Interface) {
l.client = client
}
func (l *lifecycle) Validate() error {
if l.namespaceLister == nil {
return fmt.Errorf("missing namespaceLister")
}
if l.client == nil {
return fmt.Errorf("missing client")
}
return nil
}