blob: 573d948a9849f24b53be8eb9e1712fdc3257a882 [file] [log] [blame]
Matthias Andreas Benkard832a54e2019-01-29 09:27:38 +01001/*
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 reference
18
19import (
20 "errors"
21 "fmt"
22 "net/url"
23 "strings"
24
25 "k8s.io/api/core/v1"
26 "k8s.io/apimachinery/pkg/api/meta"
27 metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
28 "k8s.io/apimachinery/pkg/runtime"
29)
30
31var (
32 // Errors that could be returned by GetReference.
33 ErrNilObject = errors.New("can't reference a nil object")
34 ErrNoSelfLink = errors.New("selfLink was empty, can't make reference")
35)
36
37// GetReference returns an ObjectReference which refers to the given
38// object, or an error if the object doesn't follow the conventions
39// that would allow this.
40// TODO: should take a meta.Interface see http://issue.k8s.io/7127
41func GetReference(scheme *runtime.Scheme, obj runtime.Object) (*v1.ObjectReference, error) {
42 if obj == nil {
43 return nil, ErrNilObject
44 }
45 if ref, ok := obj.(*v1.ObjectReference); ok {
46 // Don't make a reference to a reference.
47 return ref, nil
48 }
49
50 gvk := obj.GetObjectKind().GroupVersionKind()
51
52 // if the object referenced is actually persisted, we can just get kind from meta
53 // if we are building an object reference to something not yet persisted, we should fallback to scheme
54 kind := gvk.Kind
55 if len(kind) == 0 {
56 // TODO: this is wrong
57 gvks, _, err := scheme.ObjectKinds(obj)
58 if err != nil {
59 return nil, err
60 }
61 kind = gvks[0].Kind
62 }
63
64 // An object that implements only List has enough metadata to build a reference
65 var listMeta metav1.Common
66 objectMeta, err := meta.Accessor(obj)
67 if err != nil {
68 listMeta, err = meta.CommonAccessor(obj)
69 if err != nil {
70 return nil, err
71 }
72 } else {
73 listMeta = objectMeta
74 }
75
76 // if the object referenced is actually persisted, we can also get version from meta
77 version := gvk.GroupVersion().String()
78 if len(version) == 0 {
79 selfLink := listMeta.GetSelfLink()
80 if len(selfLink) == 0 {
81 return nil, ErrNoSelfLink
82 }
83 selfLinkUrl, err := url.Parse(selfLink)
84 if err != nil {
85 return nil, err
86 }
87 // example paths: /<prefix>/<version>/*
88 parts := strings.Split(selfLinkUrl.Path, "/")
89 if len(parts) < 4 {
90 return nil, fmt.Errorf("unexpected self link format: '%v'; got version '%v'", selfLink, version)
91 }
92 if parts[1] == "api" {
93 version = parts[2]
94 } else {
95 version = parts[2] + "/" + parts[3]
96 }
97 }
98
99 // only has list metadata
100 if objectMeta == nil {
101 return &v1.ObjectReference{
102 Kind: kind,
103 APIVersion: version,
104 ResourceVersion: listMeta.GetResourceVersion(),
105 }, nil
106 }
107
108 return &v1.ObjectReference{
109 Kind: kind,
110 APIVersion: version,
111 Name: objectMeta.GetName(),
112 Namespace: objectMeta.GetNamespace(),
113 UID: objectMeta.GetUID(),
114 ResourceVersion: objectMeta.GetResourceVersion(),
115 }, nil
116}
117
118// GetPartialReference is exactly like GetReference, but allows you to set the FieldPath.
119func GetPartialReference(scheme *runtime.Scheme, obj runtime.Object, fieldPath string) (*v1.ObjectReference, error) {
120 ref, err := GetReference(scheme, obj)
121 if err != nil {
122 return nil, err
123 }
124 ref.FieldPath = fieldPath
125 return ref, nil
126}