1/*
2Copyright 2014 The Kubernetes Authors.
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8    http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15*/
16
17package admission
18
19import (
20	"context"
21	"io"
22
23	"k8s.io/apimachinery/pkg/runtime"
24	"k8s.io/apimachinery/pkg/runtime/schema"
25	auditinternal "k8s.io/apiserver/pkg/apis/audit"
26	"k8s.io/apiserver/pkg/authentication/user"
27)
28
29// Attributes is an interface used by AdmissionController to get information about a request
30// that is used to make an admission decision.
31type Attributes interface {
32	// GetName returns the name of the object as presented in the request.  On a CREATE operation, the client
33	// may omit name and rely on the server to generate the name.  If that is the case, this method will return
34	// the empty string
35	GetName() string
36	// GetNamespace is the namespace associated with the request (if any)
37	GetNamespace() string
38	// GetResource is the name of the resource being requested.  This is not the kind.  For example: pods
39	GetResource() schema.GroupVersionResource
40	// GetSubresource is the name of the subresource being requested.  This is a different resource, scoped to the parent resource, but it may have a different kind.
41	// For instance, /pods has the resource "pods" and the kind "Pod", while /pods/foo/status has the resource "pods", the sub resource "status", and the kind "Pod"
42	// (because status operates on pods). The binding resource for a pod though may be /pods/foo/binding, which has resource "pods", subresource "binding", and kind "Binding".
43	GetSubresource() string
44	// GetOperation is the operation being performed
45	GetOperation() Operation
46	// GetOperationOptions is the options for the operation being performed
47	GetOperationOptions() runtime.Object
48	// IsDryRun indicates that modifications will definitely not be persisted for this request. This is to prevent
49	// admission controllers with side effects and a method of reconciliation from being overwhelmed.
50	// However, a value of false for this does not mean that the modification will be persisted, because it
51	// could still be rejected by a subsequent validation step.
52	IsDryRun() bool
53	// GetObject is the object from the incoming request prior to default values being applied
54	GetObject() runtime.Object
55	// GetOldObject is the existing object. Only populated for UPDATE requests.
56	GetOldObject() runtime.Object
57	// GetKind is the type of object being manipulated.  For example: Pod
58	GetKind() schema.GroupVersionKind
59	// GetUserInfo is information about the requesting user
60	GetUserInfo() user.Info
61
62	// AddAnnotation sets annotation according to key-value pair. The key should be qualified, e.g., podsecuritypolicy.admission.k8s.io/admit-policy, where
63	// "podsecuritypolicy" is the name of the plugin, "admission.k8s.io" is the name of the organization, "admit-policy" is the key name.
64	// An error is returned if the format of key is invalid. When trying to overwrite annotation with a new value, an error is returned.
65	// Both ValidationInterface and MutationInterface are allowed to add Annotations.
66	// By default, an annotation gets logged into audit event if the request's audit level is greater or
67	// equal to Metadata.
68	AddAnnotation(key, value string) error
69
70	// AddAnnotationWithLevel sets annotation according to key-value pair with additional intended audit level.
71	// An Annotation gets logged into audit event if the request's audit level is greater or equal to the
72	// intended audit level.
73	AddAnnotationWithLevel(key, value string, level auditinternal.Level) error
74
75	// GetReinvocationContext tracks the admission request information relevant to the re-invocation policy.
76	GetReinvocationContext() ReinvocationContext
77}
78
79// ObjectInterfaces is an interface used by AdmissionController to get object interfaces
80// such as Converter or Defaulter. These interfaces are normally coming from Request Scope
81// to handle special cases like CRDs.
82type ObjectInterfaces interface {
83	// GetObjectCreater is the ObjectCreator appropriate for the requested object.
84	GetObjectCreater() runtime.ObjectCreater
85	// GetObjectTyper is the ObjectTyper appropriate for the requested object.
86	GetObjectTyper() runtime.ObjectTyper
87	// GetObjectDefaulter is the ObjectDefaulter appropriate for the requested object.
88	GetObjectDefaulter() runtime.ObjectDefaulter
89	// GetObjectConvertor is the ObjectConvertor appropriate for the requested object.
90	GetObjectConvertor() runtime.ObjectConvertor
91	// GetEquivalentResourceMapper is the EquivalentResourceMapper appropriate for finding equivalent resources and expected kind for the requested object.
92	GetEquivalentResourceMapper() runtime.EquivalentResourceMapper
93}
94
95// privateAnnotationsGetter is a private interface which allows users to get annotations from Attributes.
96type privateAnnotationsGetter interface {
97	getAnnotations(maxLevel auditinternal.Level) map[string]string
98}
99
100// AnnotationsGetter allows users to get annotations from Attributes. An alternate Attribute should implement
101// this interface.
102type AnnotationsGetter interface {
103	GetAnnotations(maxLevel auditinternal.Level) map[string]string
104}
105
106// ReinvocationContext provides access to the admission related state required to implement the re-invocation policy.
107type ReinvocationContext interface {
108	// IsReinvoke returns true if the current admission check is a re-invocation.
109	IsReinvoke() bool
110	// SetIsReinvoke sets the current admission check as a re-invocation.
111	SetIsReinvoke()
112	// ShouldReinvoke returns true if any plugin has requested a re-invocation.
113	ShouldReinvoke() bool
114	// SetShouldReinvoke signals that a re-invocation is desired.
115	SetShouldReinvoke()
116	// AddValue set a value for a plugin name, possibly overriding a previous value.
117	SetValue(plugin string, v interface{})
118	// Value reads a value for a webhook.
119	Value(plugin string) interface{}
120}
121
122// Interface is an abstract, pluggable interface for Admission Control decisions.
123type Interface interface {
124	// Handles returns true if this admission controller can handle the given operation
125	// where operation can be one of CREATE, UPDATE, DELETE, or CONNECT
126	Handles(operation Operation) bool
127}
128
129type MutationInterface interface {
130	Interface
131
132	// Admit makes an admission decision based on the request attributes.
133	// Context is used only for timeout/deadline/cancellation and tracing information.
134	Admit(ctx context.Context, a Attributes, o ObjectInterfaces) (err error)
135}
136
137// ValidationInterface is an abstract, pluggable interface for Admission Control decisions.
138type ValidationInterface interface {
139	Interface
140
141	// Validate makes an admission decision based on the request attributes.  It is NOT allowed to mutate
142	// Context is used only for timeout/deadline/cancellation and tracing information.
143	Validate(ctx context.Context, a Attributes, o ObjectInterfaces) (err error)
144}
145
146// Operation is the type of resource operation being checked for admission control
147type Operation string
148
149// Operation constants
150const (
151	Create  Operation = "CREATE"
152	Update  Operation = "UPDATE"
153	Delete  Operation = "DELETE"
154	Connect Operation = "CONNECT"
155)
156
157// PluginInitializer is used for initialization of shareable resources between admission plugins.
158// After initialization the resources have to be set separately
159type PluginInitializer interface {
160	Initialize(plugin Interface)
161}
162
163// InitializationValidator holds ValidateInitialization functions, which are responsible for validation of initialized
164// shared resources and should be implemented on admission plugins
165type InitializationValidator interface {
166	ValidateInitialization() error
167}
168
169// ConfigProvider provides a way to get configuration for an admission plugin based on its name
170type ConfigProvider interface {
171	ConfigFor(pluginName string) (io.Reader, error)
172}
173