cmd/pinniped: add generate-markdown-help for generating CLI doc

This command is hidden. We want to use this to generate our CLI reference docs
upon release.

Signed-off-by: Andrew Keesler <akeesler@vmware.com>

cmd/pinniped/cmd/generate_markdown_help.go

@@ -0,0 +1,114 @@
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package cmd
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/cobra/doc"
+)
+
+//nolint: gochecknoinits
+func init() {
+	rootCmd.AddCommand(generateMarkdownHelpCommand())
+}
+
+func generateMarkdownHelpCommand() *cobra.Command {
+	return &cobra.Command{
+		Args:         cobra.NoArgs,
+		Use:          "generate-markdown-help",
+		Short:        "Generate markdown help for the current set of non-hidden CLI commands",
+		SilenceUsage: true,
+		Hidden:       true,
+		RunE:         runGenerateMarkdownHelp,
+	}
+}
+
+func runGenerateMarkdownHelp(cmd *cobra.Command, _ []string) error {
+	var generated bytes.Buffer
+	if err := generate(&generated); err != nil {
+		return err
+	}
+	if err := write(cmd.OutOrStdout(), &generated, "###### Auto generated by spf13/cobra"); err != nil {
+		return err
+	}
+	return nil
+}
+
+func generate(w io.Writer) error {
+	if err := generateHeader(w); err != nil {
+		return err
+	}
+	if err := generateCommand(w, rootCmd); err != nil {
+		return err
+	}
+	return nil
+}
+
+func generateHeader(w io.Writer) error {
+	_, err := fmt.Fprintf(w, `---
+title: Command-Line Options Reference
+description: Reference for the `+"`pinniped`"+` command-line tool
+cascade:
+  layout: docs
+menu:
+  docs:
+    name: Command-Line Options
+    weight: 30
+    parent: reference
+---
+
+`)
+	return err
+}
+
+func generateCommand(w io.Writer, command *cobra.Command) error {
+	for _, command := range command.Commands() {
+		// if this node is hidden, don't traverse it or its descendents
+		if command.Hidden {
+			continue
+		}
+
+		// generate children
+		if err := generateCommand(w, command); err != nil {
+			return err
+		}
+
+		// generate self, but only if we are a command that people would run to do something interesting
+		if command.Run != nil || command.RunE != nil {
+			if err := doc.GenMarkdownCustom(command, w, func(_ string) string { return "" }); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func write(w io.Writer, r io.Reader, unwantedPrefixes ...string) error {
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		line := s.Text()
+		if !containsPrefix(line, unwantedPrefixes) {
+			if _, err := fmt.Fprintln(w, line); err != nil {
+				return err
+			}
+		}
+	}
+	return s.Err()
+}
+
+func containsPrefix(s string, prefixes []string) bool {
+	for _, prefix := range prefixes {
+		if strings.HasPrefix(s, prefix) {
+			return true
+		}
+	}
+	return false
+}

go.sum

@@ -141,7 +141,9 @@ github.com/coreos/go-systemd v0.0.0-20190719114852-fd7a80b32e1f/go.mod h1:F5haX7
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f h1:lBNOc5arjvs8E5mO2tbpBpLoyyu8B6e44T7hJy6potg=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
+github.com/cpuguy83/go-md2man v1.0.10 h1:BSKMNlYxDvnunlTymqtgONjNnaRV1sTpcovwwjF22jk=
 github.com/cpuguy83/go-md2man v1.0.10/go.mod h1:SmD6nW6nTyfqj6ABTjUi3V3JVMnlJmwcJI5acqYI6dE=
+github.com/cpuguy83/go-md2man/v2 v2.0.0 h1:EoUDS0afbrsXAZ9YQ9jdu/mZ2sXgT1/2yyNng4PGlyM=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
@@ -902,7 +904,9 @@ github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/rs/zerolog v1.13.0/go.mod h1:YbFCdg8HfsridGWAh22vktObvhZbQsZXe4/zB0OKkWU=
 github.com/rs/zerolog v1.15.0/go.mod h1:xYTKnLHcpfU2225ny5qZjxnj9NvkumZYjJHlAThCjNc=
 github.com/rubenv/sql-migrate v0.0.0-20190212093014-1007f53448d7/go.mod h1:WS0rl9eEliYI8DPnr3TOwz4439pay+qNgzJoVya/DmY=
+github.com/russross/blackfriday v1.5.2 h1:HyvC0ARfnZBqnXwABFeSZHpKvJHJJfPz81GNueLj0oo=
 github.com/russross/blackfriday v1.5.2/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
+github.com/russross/blackfriday/v2 v2.0.1 h1:lPqVAte+HuHNfhJ/0LC98ESWRz8afy9tM/0RK8m9o+Q=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/santhosh-tekuri/jsonschema v1.2.4/go.mod h1:TEAUOeZSmIxTTuHatJzrvARHiuO9LYd+cIxzgEHCQI4=
@@ -930,6 +934,7 @@ github.com/shurcooL/highlight_diff v0.0.0-20170515013008-09bb4053de1b/go.mod h1:
 github.com/shurcooL/highlight_go v0.0.0-20170515013102-78fb10f4a5f8/go.mod h1:UDKB5a1T23gOMUJrI+uSuH0VRDStOiUVSjBTRDVBVag=
 github.com/shurcooL/octicon v0.0.0-20180602230221-c42b0e3b24d9/go.mod h1:eWdoE5JD4R5UVWDucdOPg1g2fqQRq78IQa9zlOV1vpQ=
 github.com/shurcooL/sanitized_anchor_name v0.0.0-20170918181015-86672fcb3f95/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
+github.com/shurcooL/sanitized_anchor_name v1.0.0 h1:PdmoCO6wvbs+7yrJyMORt4/BmY5IYyJwS/kOiWx8mHo=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/sirupsen/logrus v1.0.4-0.20170822132746-89742aefa4b2/go.mod h1:pMByvHTf9Beacp5x1UXfOR9xyW/9antXMhjMPG0dEzc=
 github.com/sirupsen/logrus v1.0.6/go.mod h1:pMByvHTf9Beacp5x1UXfOR9xyW/9antXMhjMPG0dEzc=