Rewrite kubectl explain to use openapi

This removes all dependencies on swagger 1.2 for explain.

pkg/kubectl/explain/fields_printer.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2017 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 explain
+
+import (
+	"k8s.io/kubernetes/pkg/kubectl/cmd/util/openapi"
+)
+
+// indentDesc is the level of indentation for descriptions.
+const indentDesc = 2
+
+// regularFieldsPrinter prints fields with their type and description.
+type regularFieldsPrinter struct {
+	Writer *Formatter
+	Error  error
+}
+
+var _ openapi.SchemaVisitor = &regularFieldsPrinter{}
+var _ fieldsPrinter = &regularFieldsPrinter{}
+
+// VisitArray prints a Array type. It is just a passthrough.
+func (f *regularFieldsPrinter) VisitArray(a *openapi.Array) {
+	a.SubType.Accept(f)
+}
+
+// VisitKind prints a Kind type. It prints each key in the kind, with
+// the type, the required flag, and the description.
+func (f *regularFieldsPrinter) VisitKind(k *openapi.Kind) {
+	for _, key := range k.Keys() {
+		v := k.Fields[key]
+		required := ""
+		if k.IsRequired(key) {
+			required = " -required-"
+		}
+
+		if err := f.Writer.Write("%s\t<%s>%s", key, GetTypeName(v), required); err != nil {
+			f.Error = err
+			return
+		}
+		if err := f.Writer.Indent(indentDesc).WriteWrapped("%s", v.GetDescription()); err != nil {
+			f.Error = err
+			return
+		}
+		if err := f.Writer.Write(""); err != nil {
+			f.Error = err
+			return
+		}
+	}
+}
+
+// VisitMap prints a Map type. It is just a passthrough.
+func (f *regularFieldsPrinter) VisitMap(m *openapi.Map) {
+	m.SubType.Accept(f)
+}
+
+// VisitPrimitive prints a Primitive type. It stops the recursion.
+func (f *regularFieldsPrinter) VisitPrimitive(p *openapi.Primitive) {
+	// Nothing to do. Shouldn't really happen.
+}
+
+// VisitReference prints a Reference type. It is just a passthrough.
+func (f *regularFieldsPrinter) VisitReference(r openapi.Reference) {
+	r.SubSchema().Accept(f)
+}
+
+// PrintFields will write the types from schema.
+func (f *regularFieldsPrinter) PrintFields(schema openapi.Schema) error {
+	schema.Accept(f)
+	return f.Error
+}