Autogenerate markdown docs for kubectl

Add test to verify generated docs are up to date.

cmd/gendocs/gen_kubectl_docs.go

@@ -0,0 +1,58 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 main
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/cmd"
+	"github.com/spf13/cobra"
+)
+
+func main() {
+	out := os.Stdout
+	// Set environment variables used by kubectl so the output is consistent,
+	// regardless of where we run.
+	os.Setenv("HOME", "/home/username")
+	kubectl := cmd.NewFactory().NewKubectlCommand(out)
+	fmt.Fprintf(out, "## %s\n\n", kubectl.Name())
+	fmt.Fprintf(out, "%s\n\n", kubectl.Short)
+	fmt.Fprintln(out, "### Commands\n")
+	for _, c := range kubectl.Commands() {
+		genMarkdown(c, nil, out)
+	}
+}
+
+func genMarkdown(command, parent *cobra.Command, out io.Writer) {
+	name := command.Name()
+	if parent != nil {
+		name = fmt.Sprintf("%s %s", parent.Name(), name)
+	}
+	fmt.Fprintf(out, "#### %s\n", name)
+	desc := command.Long
+	if len(desc) == 0 {
+		desc = command.Short
+	}
+	fmt.Fprintf(out, "%s\n\n", desc)
+	usage := command.UsageString()
+	fmt.Fprintf(out, "Usage:\n```\n%s\n```\n\n", usage[9:len(usage)-1])
+	for _, c := range command.Commands() {
+		genMarkdown(c, command, out)
+	}
+}