|
| 1 | +/* |
| 2 | +Copyright 2025 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 json |
| 18 | + |
| 19 | +import ( |
| 20 | + "encoding/json" |
| 21 | + "fmt" |
| 22 | + "io" |
| 23 | + "maps" |
| 24 | + "slices" |
| 25 | + "sort" |
| 26 | + |
| 27 | + "k8s.io/apimachinery/pkg/api/meta" |
| 28 | + "k8s.io/apimachinery/pkg/conversion" |
| 29 | + |
| 30 | + metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" |
| 31 | + "k8s.io/apimachinery/pkg/apis/meta/v1/unstructured" |
| 32 | + "k8s.io/apimachinery/pkg/runtime" |
| 33 | +) |
| 34 | + |
| 35 | +func streamEncodeCollections(obj runtime.Object, w io.Writer) (bool, error) { |
| 36 | + list, ok := obj.(*unstructured.UnstructuredList) |
| 37 | + if ok { |
| 38 | + return true, streamingEncodeUnstructuredList(w, list) |
| 39 | + } |
| 40 | + if _, ok := obj.(json.Marshaler); ok { |
| 41 | + return false, nil |
| 42 | + } |
| 43 | + typeMeta, listMeta, items, err := getListMeta(obj) |
| 44 | + if err == nil { |
| 45 | + return true, streamingEncodeList(w, typeMeta, listMeta, items) |
| 46 | + } |
| 47 | + return false, nil |
| 48 | +} |
| 49 | + |
| 50 | +// getListMeta implements list extraction logic for json stream serialization. |
| 51 | +// |
| 52 | +// Reason for a custom logic instead of reusing accessors from meta package: |
| 53 | +// * Validate json tags to prevent incompatibility with json standard package. |
| 54 | +// * ListMetaAccessor doesn't distinguish empty from nil value. |
| 55 | +// * TypeAccessort reparsing "apiVersion" and serializing it with "{group}/{version}" |
| 56 | +func getListMeta(list runtime.Object) (metav1.TypeMeta, metav1.ListMeta, []runtime.Object, error) { |
| 57 | + listValue, err := conversion.EnforcePtr(list) |
| 58 | + if err != nil { |
| 59 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, err |
| 60 | + } |
| 61 | + listType := listValue.Type() |
| 62 | + if listType.NumField() != 3 { |
| 63 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, fmt.Errorf("expected ListType to have 3 fields") |
| 64 | + } |
| 65 | + // TypeMeta |
| 66 | + typeMeta, ok := listValue.Field(0).Interface().(metav1.TypeMeta) |
| 67 | + if !ok { |
| 68 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, fmt.Errorf("expected TypeMeta field to have TypeMeta type") |
| 69 | + } |
| 70 | + if listType.Field(0).Tag.Get("json") != ",inline" { |
| 71 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, fmt.Errorf(`expected TypeMeta json field tag to be ",inline"`) |
| 72 | + } |
| 73 | + // ListMeta |
| 74 | + listMeta, ok := listValue.Field(1).Interface().(metav1.ListMeta) |
| 75 | + if !ok { |
| 76 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, fmt.Errorf("expected ListMeta field to have ListMeta type") |
| 77 | + } |
| 78 | + if listType.Field(1).Tag.Get("json") != "metadata,omitempty" { |
| 79 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, fmt.Errorf(`expected ListMeta json field tag to be "metadata,omitempty"`) |
| 80 | + } |
| 81 | + // Items |
| 82 | + items, err := meta.ExtractList(list) |
| 83 | + if err != nil { |
| 84 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, err |
| 85 | + } |
| 86 | + if listType.Field(2).Tag.Get("json") != "items" { |
| 87 | + return metav1.TypeMeta{}, metav1.ListMeta{}, nil, fmt.Errorf(`expected Items json field tag to be "items"`) |
| 88 | + } |
| 89 | + return typeMeta, listMeta, items, nil |
| 90 | +} |
| 91 | + |
| 92 | +func streamingEncodeList(w io.Writer, typeMeta metav1.TypeMeta, listMeta metav1.ListMeta, items []runtime.Object) error { |
| 93 | + // Start |
| 94 | + if _, err := w.Write([]byte(`{`)); err != nil { |
| 95 | + return err |
| 96 | + } |
| 97 | + |
| 98 | + // TypeMeta |
| 99 | + if typeMeta.Kind != "" { |
| 100 | + if err := encodeKeyValuePair(w, "kind", typeMeta.Kind, []byte(",")); err != nil { |
| 101 | + return err |
| 102 | + } |
| 103 | + } |
| 104 | + if typeMeta.APIVersion != "" { |
| 105 | + if err := encodeKeyValuePair(w, "apiVersion", typeMeta.APIVersion, []byte(",")); err != nil { |
| 106 | + return err |
| 107 | + } |
| 108 | + } |
| 109 | + |
| 110 | + // ListMeta |
| 111 | + if err := encodeKeyValuePair(w, "metadata", listMeta, []byte(",")); err != nil { |
| 112 | + return err |
| 113 | + } |
| 114 | + |
| 115 | + // Items |
| 116 | + if err := encodeItemsObjectSlice(w, items); err != nil { |
| 117 | + return err |
| 118 | + } |
| 119 | + |
| 120 | + // End |
| 121 | + _, err := w.Write([]byte("}\n")) |
| 122 | + return err |
| 123 | +} |
| 124 | + |
| 125 | +func encodeItemsObjectSlice(w io.Writer, items []runtime.Object) (err error) { |
| 126 | + if items == nil { |
| 127 | + err := encodeKeyValuePair(w, "items", nil, nil) |
| 128 | + return err |
| 129 | + } |
| 130 | + _, err = w.Write([]byte(`"items":[`)) |
| 131 | + if err != nil { |
| 132 | + return err |
| 133 | + } |
| 134 | + suffix := []byte(",") |
| 135 | + for i, item := range items { |
| 136 | + if i == len(items)-1 { |
| 137 | + suffix = nil |
| 138 | + } |
| 139 | + err := encodeValue(w, item, suffix) |
| 140 | + if err != nil { |
| 141 | + return err |
| 142 | + } |
| 143 | + } |
| 144 | + _, err = w.Write([]byte("]")) |
| 145 | + if err != nil { |
| 146 | + return err |
| 147 | + } |
| 148 | + return err |
| 149 | +} |
| 150 | + |
| 151 | +func streamingEncodeUnstructuredList(w io.Writer, list *unstructured.UnstructuredList) error { |
| 152 | + _, err := w.Write([]byte(`{`)) |
| 153 | + if err != nil { |
| 154 | + return err |
| 155 | + } |
| 156 | + keys := slices.Collect(maps.Keys(list.Object)) |
| 157 | + if _, exists := list.Object["items"]; !exists { |
| 158 | + keys = append(keys, "items") |
| 159 | + } |
| 160 | + sort.Strings(keys) |
| 161 | + |
| 162 | + suffix := []byte(",") |
| 163 | + for i, key := range keys { |
| 164 | + if i == len(keys)-1 { |
| 165 | + suffix = nil |
| 166 | + } |
| 167 | + if key == "items" { |
| 168 | + err = encodeItemsUnstructuredSlice(w, list.Items, suffix) |
| 169 | + } else { |
| 170 | + err = encodeKeyValuePair(w, key, list.Object[key], suffix) |
| 171 | + } |
| 172 | + if err != nil { |
| 173 | + return err |
| 174 | + } |
| 175 | + } |
| 176 | + _, err = w.Write([]byte("}\n")) |
| 177 | + return err |
| 178 | +} |
| 179 | + |
| 180 | +func encodeItemsUnstructuredSlice(w io.Writer, items []unstructured.Unstructured, suffix []byte) (err error) { |
| 181 | + _, err = w.Write([]byte(`"items":[`)) |
| 182 | + if err != nil { |
| 183 | + return err |
| 184 | + } |
| 185 | + comma := []byte(",") |
| 186 | + for i, item := range items { |
| 187 | + if i == len(items)-1 { |
| 188 | + comma = nil |
| 189 | + } |
| 190 | + err := encodeValue(w, item.Object, comma) |
| 191 | + if err != nil { |
| 192 | + return err |
| 193 | + } |
| 194 | + } |
| 195 | + _, err = w.Write([]byte("]")) |
| 196 | + if err != nil { |
| 197 | + return err |
| 198 | + } |
| 199 | + if len(suffix) > 0 { |
| 200 | + _, err = w.Write(suffix) |
| 201 | + } |
| 202 | + return err |
| 203 | +} |
| 204 | + |
| 205 | +func encodeKeyValuePair(w io.Writer, key string, value any, suffix []byte) (err error) { |
| 206 | + err = encodeValue(w, key, []byte(":")) |
| 207 | + if err != nil { |
| 208 | + return err |
| 209 | + } |
| 210 | + err = encodeValue(w, value, suffix) |
| 211 | + if err != nil { |
| 212 | + return err |
| 213 | + } |
| 214 | + return err |
| 215 | +} |
| 216 | + |
| 217 | +func encodeValue(w io.Writer, value any, suffix []byte) error { |
| 218 | + data, err := json.Marshal(value) |
| 219 | + if err != nil { |
| 220 | + return err |
| 221 | + } |
| 222 | + _, err = w.Write(data) |
| 223 | + if err != nil { |
| 224 | + return err |
| 225 | + } |
| 226 | + if len(suffix) > 0 { |
| 227 | + _, err = w.Write(suffix) |
| 228 | + } |
| 229 | + return err |
| 230 | +} |
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