apiextensions: add defaulting algorithm

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/schema/defaulting/algorithm.go

@@ -0,0 +1,55 @@
+/*
+Copyright 2019 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 defaulting
+
+import (
+	structuralschema "k8s.io/apiextensions-apiserver/pkg/apiserver/schema"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// Default does defaulting of x depending on default values in s.
+// Default values from s are deep-copied.
+func Default(x interface{}, s *structuralschema.Structural) {
+	if s == nil {
+		return
+	}
+
+	switch x := x.(type) {
+	case map[string]interface{}:
+		for k, prop := range s.Properties {
+			if prop.Default.Object == nil {
+				continue
+			}
+			if _, found := x[k]; !found {
+				x[k] = runtime.DeepCopyJSONValue(prop.Default.Object)
+			}
+		}
+		for k, v := range x {
+			if prop, found := s.Properties[k]; found {
+				Default(v, &prop)
+			} else if s.AdditionalProperties != nil {
+				Default(v, s.AdditionalProperties.Structural)
+			}
+		}
+	case []interface{}:
+		for _, v := range x {
+			Default(v, s.Items)
+		}
+	default:
+		// scalars, do nothing
+	}
+}

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/schema/defaulting/algorithm_test.go

@@ -0,0 +1,165 @@
+/*
+Copyright 2019 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 defaulting
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+
+	structuralschema "k8s.io/apiextensions-apiserver/pkg/apiserver/schema"
+	"k8s.io/apimachinery/pkg/util/json"
+)
+
+func TestDefault(t *testing.T) {
+	tests := []struct {
+		name     string
+		json     string
+		schema   *structuralschema.Structural
+		expected string
+	}{
+		{"empty", "null", nil, "null"},
+		{"scalar", "4", &structuralschema.Structural{
+			Generic: structuralschema.Generic{
+				Default: structuralschema.JSON{"foo"},
+			},
+		}, "4"},
+		{"scalar array", "[1,2]", &structuralschema.Structural{
+			Items: &structuralschema.Structural{
+				Generic: structuralschema.Generic{
+					Default: structuralschema.JSON{"foo"},
+				},
+			},
+		}, "[1,2]"},
+		{"object array", `[{"a":1},{"b":1},{"c":1}]`, &structuralschema.Structural{
+			Items: &structuralschema.Structural{
+				Properties: map[string]structuralschema.Structural{
+					"a": {
+						Generic: structuralschema.Generic{
+							Default: structuralschema.JSON{"A"},
+						},
+					},
+					"b": {
+						Generic: structuralschema.Generic{
+							Default: structuralschema.JSON{"B"},
+						},
+					},
+					"c": {
+						Generic: structuralschema.Generic{
+							Default: structuralschema.JSON{"C"},
+						},
+					},
+				},
+			},
+		}, `[{"a":1,"b":"B","c":"C"},{"a":"A","b":1,"c":"C"},{"a":"A","b":"B","c":1}]`},
+		{"object array object", `{"array":[{"a":1},{"b":2}],"object":{"a":1},"additionalProperties":{"x":{"a":1},"y":{"b":2}}}`, &structuralschema.Structural{
+			Properties: map[string]structuralschema.Structural{
+				"array": {
+					Items: &structuralschema.Structural{
+						Properties: map[string]structuralschema.Structural{
+							"a": {
+								Generic: structuralschema.Generic{
+									Default: structuralschema.JSON{"A"},
+								},
+							},
+							"b": {
+								Generic: structuralschema.Generic{
+									Default: structuralschema.JSON{"B"},
+								},
+							},
+						},
+					},
+				},
+				"object": {
+					Properties: map[string]structuralschema.Structural{
+						"a": {
+							Generic: structuralschema.Generic{
+								Default: structuralschema.JSON{"N"},
+							},
+						},
+						"b": {
+							Generic: structuralschema.Generic{
+								Default: structuralschema.JSON{"O"},
+							},
+						},
+					},
+				},
+				"additionalProperties": {
+					Generic: structuralschema.Generic{
+						AdditionalProperties: &structuralschema.StructuralOrBool{
+							Structural: &structuralschema.Structural{
+								Properties: map[string]structuralschema.Structural{
+									"a": {
+										Generic: structuralschema.Generic{
+											Default: structuralschema.JSON{"alpha"},
+										},
+									},
+									"b": {
+										Generic: structuralschema.Generic{
+											Default: structuralschema.JSON{"beta"},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+				"foo": {
+					Generic: structuralschema.Generic{
+						Default: structuralschema.JSON{"bar"},
+					},
+				},
+			},
+		}, `{"array":[{"a":1,"b":"B"},{"a":"A","b":2}],"object":{"a":1,"b":"O"},"additionalProperties":{"x":{"a":1,"b":"beta"},"y":{"a":"alpha","b":2}},"foo":"bar"}`},
+		{"empty and null", `[{},{"a":1},{"a":0},{"a":0.0},{"a":""},{"a":null},{"a":[]},{"a":{}}]`, &structuralschema.Structural{
+			Items: &structuralschema.Structural{
+				Properties: map[string]structuralschema.Structural{
+					"a": {
+						Generic: structuralschema.Generic{
+							Default: structuralschema.JSON{"A"},
+						},
+					},
+				},
+			},
+		}, `[{"a":"A"},{"a":1},{"a":0},{"a":0.0},{"a":""},{"a":null},{"a":[]},{"a":{}}]`},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var in interface{}
+			if err := json.Unmarshal([]byte(tt.json), &in); err != nil {
+				t.Fatal(err)
+			}
+
+			var expected interface{}
+			if err := json.Unmarshal([]byte(tt.expected), &expected); err != nil {
+				t.Fatal(err)
+			}
+
+			Default(in, tt.schema)
+			if !reflect.DeepEqual(in, expected) {
+				var buf bytes.Buffer
+				enc := json.NewEncoder(&buf)
+				enc.SetIndent("", "  ")
+				err := enc.Encode(in)
+				if err != nil {
+					t.Fatalf("unexpected result mashalling error: %v", err)
+				}
+				t.Errorf("expected: %s\ngot: %s", tt.expected, buf.String())
+			}
+		})
+	}
+}