schema from value function

Author: jennybuckley

schema/fromvalue.go

@@ -0,0 +1,61 @@
+/*
+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 schema
+
+import (
+	"sigs.k8s.io/structured-merge-diff/value"
+)
+
+// FromValue creates a schema from a value v
+func FromValue(name string, v value.Value) *Schema {
+	atom := atomFor(v)
+	typeDef := TypeDef{
+		Name: name,
+		Atom: atom,
+	}
+	return &Schema{
+		Types: []TypeDef{typeDef},
+	}
+}
+
+func atomFor(v value.Value) Atom {
+	switch {
+	// Untyped cases (handled at the bottom of this function)
+	case v.Null:
+	case v.ListValue != nil:
+	case v.FloatValue != nil:
+	case v.IntValue != nil:
+	case v.StringValue != nil:
+	case v.BooleanValue != nil:
+	// Recursive case
+	case v.MapValue != nil:
+		s := Struct{}
+		for i := range v.MapValue.Items {
+			child := v.MapValue.Items[i]
+			field := StructField{
+				Name: child.Name,
+				Type: TypeRef{
+					Inlined: atomFor(child.Value),
+				},
+			}
+			s.Fields = append(s.Fields, field)
+		}
+		return Atom{Struct: &s}
+	}
+
+	return Atom{Untyped: &Untyped{}}
+}

schema/fromvalue_test.go

@@ -0,0 +1,100 @@
+/*
+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 schema_test
+
+import (
+	"reflect"
+	"testing"
+
+	"gopkg.in/yaml.v2"
+	"sigs.k8s.io/structured-merge-diff/schema"
+	"sigs.k8s.io/structured-merge-diff/value"
+)
+
+const (
+	typeName = "test"
+)
+
+func TestFromValue(t *testing.T) {
+
+	table := []struct {
+		objYAML string
+		schema  string
+	}{
+		{`a: a`, `
+types: 
+- name: ` + typeName + `
+  struct:
+    fields:
+    - name: a
+      type:
+        untyped: {}`},
+		{`{"a": [{"a": null}]}`, `
+types: 
+- name: ` + typeName + `
+  struct:
+    fields:
+    - name: a
+      type:
+        untyped: {}`},
+		{`{"a": null}`, `
+types: 
+- name: ` + typeName + `
+  struct:
+    fields:
+    - name: a
+      type:
+        untyped: {}`},
+		{`{"q": {"y": 6, "b": [7, 8, 9]}}`, `
+types: 
+- name: ` + typeName + `
+  struct:
+    fields:
+    - name: q
+      type:
+        struct:
+          fields:
+          - name: y
+            type:
+              untyped: {}
+          - name: b
+            type:
+              untyped: {}`},
+	}
+
+	for _, tt := range table {
+		tt := tt
+		t.Run(tt.objYAML, func(t *testing.T) {
+			t.Parallel()
+			v, err := value.FromYAML([]byte(tt.objYAML))
+			if err != nil {
+				t.Fatalf("couldn't parse: %v", err)
+			}
+			got := schema.FromValue(typeName, v)
+
+			expected := &schema.Schema{}
+			err = yaml.Unmarshal([]byte(tt.schema), expected)
+			if err != nil {
+				t.Fatalf("couldn't parse: %v", err)
+			}
+
+			if !reflect.DeepEqual(got, expected) {
+				t.Errorf("wanted\n%+v\nbut got\n%+v\n", expected, got)
+			}
+		})
+	}
+}