Matthias Andreas Benkard | 832a54e | 2019-01-29 09:27:38 +0100 | [diff] [blame] | 1 | /* |
| 2 | Copyright 2014 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 etcd |
| 18 | |
| 19 | import ( |
| 20 | "strconv" |
| 21 | |
| 22 | "k8s.io/apimachinery/pkg/api/meta" |
| 23 | "k8s.io/apimachinery/pkg/runtime" |
| 24 | "k8s.io/apimachinery/pkg/util/validation/field" |
| 25 | "k8s.io/apiserver/pkg/storage" |
| 26 | ) |
| 27 | |
| 28 | // APIObjectVersioner implements versioning and extracting etcd node information |
| 29 | // for objects that have an embedded ObjectMeta or ListMeta field. |
| 30 | type APIObjectVersioner struct{} |
| 31 | |
| 32 | // UpdateObject implements Versioner |
| 33 | func (a APIObjectVersioner) UpdateObject(obj runtime.Object, resourceVersion uint64) error { |
| 34 | accessor, err := meta.Accessor(obj) |
| 35 | if err != nil { |
| 36 | return err |
| 37 | } |
| 38 | versionString := "" |
| 39 | if resourceVersion != 0 { |
| 40 | versionString = strconv.FormatUint(resourceVersion, 10) |
| 41 | } |
| 42 | accessor.SetResourceVersion(versionString) |
| 43 | return nil |
| 44 | } |
| 45 | |
| 46 | // UpdateList implements Versioner |
| 47 | func (a APIObjectVersioner) UpdateList(obj runtime.Object, resourceVersion uint64, nextKey string) error { |
| 48 | listAccessor, err := meta.ListAccessor(obj) |
| 49 | if err != nil || listAccessor == nil { |
| 50 | return err |
| 51 | } |
| 52 | versionString := "" |
| 53 | if resourceVersion != 0 { |
| 54 | versionString = strconv.FormatUint(resourceVersion, 10) |
| 55 | } |
| 56 | listAccessor.SetResourceVersion(versionString) |
| 57 | listAccessor.SetContinue(nextKey) |
| 58 | return nil |
| 59 | } |
| 60 | |
| 61 | // PrepareObjectForStorage clears resource version and self link prior to writing to etcd. |
| 62 | func (a APIObjectVersioner) PrepareObjectForStorage(obj runtime.Object) error { |
| 63 | accessor, err := meta.Accessor(obj) |
| 64 | if err != nil { |
| 65 | return err |
| 66 | } |
| 67 | accessor.SetResourceVersion("") |
| 68 | accessor.SetSelfLink("") |
| 69 | return nil |
| 70 | } |
| 71 | |
| 72 | // ObjectResourceVersion implements Versioner |
| 73 | func (a APIObjectVersioner) ObjectResourceVersion(obj runtime.Object) (uint64, error) { |
| 74 | accessor, err := meta.Accessor(obj) |
| 75 | if err != nil { |
| 76 | return 0, err |
| 77 | } |
| 78 | version := accessor.GetResourceVersion() |
| 79 | if len(version) == 0 { |
| 80 | return 0, nil |
| 81 | } |
| 82 | return strconv.ParseUint(version, 10, 64) |
| 83 | } |
| 84 | |
| 85 | // ParseWatchResourceVersion takes a resource version argument and converts it to |
| 86 | // the etcd version we should pass to helper.Watch(). Because resourceVersion is |
| 87 | // an opaque value, the default watch behavior for non-zero watch is to watch |
| 88 | // the next value (if you pass "1", you will see updates from "2" onwards). |
| 89 | func (a APIObjectVersioner) ParseWatchResourceVersion(resourceVersion string) (uint64, error) { |
| 90 | if resourceVersion == "" || resourceVersion == "0" { |
| 91 | return 0, nil |
| 92 | } |
| 93 | version, err := strconv.ParseUint(resourceVersion, 10, 64) |
| 94 | if err != nil { |
| 95 | return 0, storage.NewInvalidError(field.ErrorList{ |
| 96 | // Validation errors are supposed to return version-specific field |
| 97 | // paths, but this is probably close enough. |
| 98 | field.Invalid(field.NewPath("resourceVersion"), resourceVersion, err.Error()), |
| 99 | }) |
| 100 | } |
| 101 | return version, nil |
| 102 | } |
| 103 | |
| 104 | // ParseListResourceVersion takes a resource version argument and converts it to |
| 105 | // the etcd version. |
| 106 | // TODO: reevaluate whether it is really clearer to have both this and the |
| 107 | // Watch version of this function, since they perform the same logic. |
| 108 | func (a APIObjectVersioner) ParseListResourceVersion(resourceVersion string) (uint64, error) { |
| 109 | if resourceVersion == "" { |
| 110 | return 0, nil |
| 111 | } |
| 112 | version, err := strconv.ParseUint(resourceVersion, 10, 64) |
| 113 | if err != nil { |
| 114 | return 0, storage.NewInvalidError(field.ErrorList{ |
| 115 | // Validation errors are supposed to return version-specific field |
| 116 | // paths, but this is probably close enough. |
| 117 | field.Invalid(field.NewPath("resourceVersion"), resourceVersion, err.Error()), |
| 118 | }) |
| 119 | } |
| 120 | return version, nil |
| 121 | } |
| 122 | |
| 123 | // APIObjectVersioner implements Versioner |
| 124 | var Versioner storage.Versioner = APIObjectVersioner{} |
| 125 | |
| 126 | // CompareResourceVersion compares etcd resource versions. Outside this API they are all strings, |
| 127 | // but etcd resource versions are special, they're actually ints, so we can easily compare them. |
| 128 | func (a APIObjectVersioner) CompareResourceVersion(lhs, rhs runtime.Object) int { |
| 129 | lhsVersion, err := Versioner.ObjectResourceVersion(lhs) |
| 130 | if err != nil { |
| 131 | // coder error |
| 132 | panic(err) |
| 133 | } |
| 134 | rhsVersion, err := Versioner.ObjectResourceVersion(rhs) |
| 135 | if err != nil { |
| 136 | // coder error |
| 137 | panic(err) |
| 138 | } |
| 139 | |
| 140 | if lhsVersion == rhsVersion { |
| 141 | return 0 |
| 142 | } |
| 143 | if lhsVersion < rhsVersion { |
| 144 | return -1 |
| 145 | } |
| 146 | |
| 147 | return 1 |
| 148 | } |