doc: add ReST doc generation (#537)

README.md

@@ -42,8 +42,7 @@ Many of the most widely used Go projects are built using Cobra including:
   * [Usage Message](#usage-message)
   * [PreRun and PostRun Hooks](#prerun-and-postrun-hooks)
   * [Suggestions when "unknown command" happens](#suggestions-when-unknown-command-happens)
-  * [Generating Markdown-formatted docs](#generating-markdown-formatted-docs)
+  * [Generating documentation for your command](#generating-documentation-for-your-command)
-  * [Generating man pages](#generating-man-pages)
   * [Generating bash completions](#generating-bash-completions)
 - [Contributing](#contributing)
 - [License](#license)
@@ -682,13 +681,13 @@ Did you mean this?
 Run 'kubectl help' for usage.
 ```
 
-## Generating Markdown-formatted docs
+## Generating documentation for your command
 
-Cobra can generate a Markdown-formatted document based on the subcommands, flags, etc. A simple example of how to do this for your command can be found in [Markdown Docs](doc/md_docs.md).
+Cobra can generate documentation based on subcommands, flags, etc. in the following formats:
 
-## Generating man pages
+- [Markdown](doc/md_docs.md)
-
+- [ReStructured Text](doc/rest_docs.md)
-Cobra can generate a man page based on the subcommands, flags, etc. A simple example of how to do this for your command can be found in [Man Docs](doc/man_docs.md).
+- [Man Page](doc/man_docs.md)
 
 ## Generating bash completions
 

doc/rest_docs.go

@@ -0,0 +1,185 @@
+//Copyright 2015 Red Hat 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 doc
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/spf13/cobra"
+)
+
+func printOptionsReST(buf *bytes.Buffer, cmd *cobra.Command, name string) error {
+	flags := cmd.NonInheritedFlags()
+	flags.SetOutput(buf)
+	if flags.HasFlags() {
+		buf.WriteString("Options\n")
+		buf.WriteString("~~~~~~~\n\n::\n\n")
+		flags.PrintDefaults()
+		buf.WriteString("\n")
+	}
+
+	parentFlags := cmd.InheritedFlags()
+	parentFlags.SetOutput(buf)
+	if parentFlags.HasFlags() {
+		buf.WriteString("Options inherited from parent commands\n")
+		buf.WriteString("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n\n::\n\n")
+		parentFlags.PrintDefaults()
+		buf.WriteString("\n")
+	}
+	return nil
+}
+
+// linkHandler for default ReST hyperlink markup
+func defaultLinkHandler(name, ref string) string {
+	return fmt.Sprintf("`%s <%s.rst>`_", name, ref)
+}
+
+// GenReST creates reStructured Text output.
+func GenReST(cmd *cobra.Command, w io.Writer) error {
+	return GenReSTCustom(cmd, w, defaultLinkHandler)
+}
+
+// GenReSTCustom creates custom reStructured Text output.
+func GenReSTCustom(cmd *cobra.Command, w io.Writer, linkHandler func(string, string) string) error {
+	cmd.InitDefaultHelpCmd()
+	cmd.InitDefaultHelpFlag()
+
+	buf := new(bytes.Buffer)
+	name := cmd.CommandPath()
+
+	short := cmd.Short
+	long := cmd.Long
+	if len(long) == 0 {
+		long = short
+	}
+	ref := strings.Replace(name, " ", "_", -1)
+
+	buf.WriteString(".. _" + ref + ":\n\n")
+	buf.WriteString(name + "\n")
+	buf.WriteString(strings.Repeat("-", len(name)) + "\n\n")
+	buf.WriteString(short + "\n\n")
+	buf.WriteString("Synopsis\n")
+	buf.WriteString("~~~~~~~~\n\n")
+	buf.WriteString("\n" + long + "\n\n")
+
+	if cmd.Runnable() {
+		buf.WriteString(fmt.Sprintf("::\n\n  %s\n\n", cmd.UseLine()))
+	}
+
+	if len(cmd.Example) > 0 {
+		buf.WriteString("Examples\n")
+		buf.WriteString("~~~~~~~~\n\n")
+		buf.WriteString(fmt.Sprintf("::\n\n%s\n\n", indentString(cmd.Example, "  ")))
+	}
+
+	if err := printOptionsReST(buf, cmd, name); err != nil {
+		return err
+	}
+	if hasSeeAlso(cmd) {
+		buf.WriteString("SEE ALSO\n")
+		buf.WriteString("~~~~~~~~\n\n")
+		if cmd.HasParent() {
+			parent := cmd.Parent()
+			pname := parent.CommandPath()
+			ref = strings.Replace(pname, " ", "_", -1)
+			buf.WriteString(fmt.Sprintf("* %s \t - %s\n", linkHandler(pname, ref), parent.Short))
+			cmd.VisitParents(func(c *cobra.Command) {
+				if c.DisableAutoGenTag {
+					cmd.DisableAutoGenTag = c.DisableAutoGenTag
+				}
+			})
+		}
+
+		children := cmd.Commands()
+		sort.Sort(byName(children))
+
+		for _, child := range children {
+			if !child.IsAvailableCommand() || child.IsAdditionalHelpTopicCommand() {
+				continue
+			}
+			cname := name + " " + child.Name()
+			ref = strings.Replace(cname, " ", "_", -1)
+			buf.WriteString(fmt.Sprintf("* %s \t - %s\n", linkHandler(cname, ref), child.Short))
+		}
+		buf.WriteString("\n")
+	}
+	if !cmd.DisableAutoGenTag {
+		buf.WriteString("*Auto generated by spf13/cobra on " + time.Now().Format("2-Jan-2006") + "*\n")
+	}
+	_, err := buf.WriteTo(w)
+	return err
+}
+
+// GenReSTTree will generate a ReST page for this command and all
+// descendants in the directory given.
+// This function may not work correctly if your command names have `-` in them.
+// If you have `cmd` with two subcmds, `sub` and `sub-third`,
+// and `sub` has a subcommand called `third`, it is undefined which
+// help output will be in the file `cmd-sub-third.1`.
+func GenReSTTree(cmd *cobra.Command, dir string) error {
+	emptyStr := func(s string) string { return "" }
+	return GenReSTTreeCustom(cmd, dir, emptyStr, defaultLinkHandler)
+}
+
+// GenReSTTreeCustom is the the same as GenReSTTree, but
+// with custom filePrepender and linkHandler.
+func GenReSTTreeCustom(cmd *cobra.Command, dir string, filePrepender func(string) string, linkHandler func(string, string) string) error {
+	for _, c := range cmd.Commands() {
+		if !c.IsAvailableCommand() || c.IsAdditionalHelpTopicCommand() {
+			continue
+		}
+		if err := GenReSTTreeCustom(c, dir, filePrepender, linkHandler); err != nil {
+			return err
+		}
+	}
+
+	basename := strings.Replace(cmd.CommandPath(), " ", "_", -1) + ".rst"
+	filename := filepath.Join(dir, basename)
+	f, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if _, err := io.WriteString(f, filePrepender(filename)); err != nil {
+		return err
+	}
+	if err := GenReSTCustom(cmd, f, linkHandler); err != nil {
+		return err
+	}
+	return nil
+}
+
+// adapted from: https://github.com/kr/text/blob/main/indent.go
+func indentString(s, p string) string {
+	var res []byte
+	b := []byte(s)
+	prefix := []byte(p)
+	bol := true
+	for _, c := range b {
+		if bol && c != '\n' {
+			res = append(res, prefix...)
+		}
+		res = append(res, c)
+		bol = c == '\n'
+	}
+	return string(res)
+}

doc/rest_docs.md

@@ -0,0 +1,114 @@
+# Generating ReStructured Text Docs For Your Own cobra.Command
+
+Generating ReST pages from a cobra command is incredibly easy. An example is as follows:
+
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/cobra/doc"
+)
+
+func main() {
+	cmd := &cobra.Command{
+		Use:   "test",
+		Short: "my test program",
+	}
+	err := doc.GenReSTTree(cmd, "/tmp")
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+```
+
+That will get you a ReST document `/tmp/test.rst`
+
+## Generate ReST docs for the entire command tree
+
+This program can actually generate docs for the kubectl command in the kubernetes project
+
+```go
+package main
+
+import (
+	"log"
+	"io/ioutil"
+	"os"
+
+	"k8s.io/kubernetes/pkg/kubectl/cmd"
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+
+	"github.com/spf13/cobra/doc"
+)
+
+func main() {
+	kubectl := cmd.NewKubectlCommand(cmdutil.NewFactory(nil), os.Stdin, ioutil.Discard, ioutil.Discard)
+	err := doc.GenReSTTree(kubectl, "./")
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+```
+
+This will generate a whole series of files, one for each command in the tree, in the directory specified (in this case "./")
+
+## Generate ReST docs for a single command
+
+You may wish to have more control over the output, or only generate for a single command, instead of the entire command tree. If this is the case you may prefer to `GenReST` instead of `GenReSTTree`
+
+```go
+	out := new(bytes.Buffer)
+	err := doc.GenReST(cmd, out)
+	if err != nil {
+		log.Fatal(err)
+	}
+```
+
+This will write the ReST doc for ONLY "cmd" into the out, buffer.
+
+## Customize the output
+
+Both `GenReST` and `GenReSTTree` have alternate versions with callbacks to get some control of the output:
+
+```go
+func GenReSTTreeCustom(cmd *Command, dir string, filePrepender func(string) string, linkHandler func(string, string) string) error {
+	//...
+}
+```
+
+```go
+func GenReSTCustom(cmd *Command, out *bytes.Buffer, linkHandler func(string, string) string) error {
+	//...
+}
+```
+
+The `filePrepender` will prepend the return value given the full filepath to the rendered ReST file. A common use case is to add front matter to use the generated documentation with [Hugo](http://gohugo.io/):
+
+```go
+const fmTemplate = `---
+date: %s
+title: "%s"
+slug: %s
+url: %s
+---
+`
+filePrepender := func(filename string) string {
+	now := time.Now().Format(time.RFC3339)
+	name := filepath.Base(filename)
+	base := strings.TrimSuffix(name, path.Ext(name))
+	url := "/commands/" + strings.ToLower(base) + "/"
+	return fmt.Sprintf(fmTemplate, now, strings.Replace(base, "_", " ", -1), base, url)
+}
+```
+
+The `linkHandler` can be used to customize the rendered links to the commands, given a command name and reference. This is useful while converting rst to html or while generating documentation with tools like Sphinx where `:ref:` is used:
+
+```go
+// Sphinx cross-referencing format
+linkHandler := func(name, ref string) string {
+    return fmt.Sprintf(":ref:`%s <%s>`", name, ref)
+}
+```

doc/rest_docs_test.go

@@ -0,0 +1,124 @@
+package doc
+
+import (
+	"bytes"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/spf13/cobra"
+)
+
+func TestGenRSTDoc(t *testing.T) {
+	c := initializeWithRootCmd()
+	// Need two commands to run the command alphabetical sort
+	cmdEcho.AddCommand(cmdTimes, cmdEchoSub, cmdDeprecated)
+	c.AddCommand(cmdPrint, cmdEcho)
+	cmdRootWithRun.PersistentFlags().StringVarP(&flags2a, "rootflag", "r", "two", strtwoParentHelp)
+
+	out := new(bytes.Buffer)
+
+	// We generate on s subcommand so we have both subcommands and parents
+	if err := GenReST(cmdEcho, out); err != nil {
+		t.Fatal(err)
+	}
+	found := out.String()
+
+	// Our description
+	expected := cmdEcho.Long
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// Better have our example
+	expected = cmdEcho.Example
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// A local flag
+	expected = "boolone"
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// persistent flag on parent
+	expected = "rootflag"
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// We better output info about our parent
+	expected = cmdRootWithRun.Short
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// And about subcommands
+	expected = cmdEchoSub.Short
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	unexpected := cmdDeprecated.Short
+	if strings.Contains(found, unexpected) {
+		t.Errorf("Unexpected response.\nFound: %v\nBut should not have!!\n", unexpected)
+	}
+}
+
+func TestGenRSTNoTag(t *testing.T) {
+	c := initializeWithRootCmd()
+	// Need two commands to run the command alphabetical sort
+	cmdEcho.AddCommand(cmdTimes, cmdEchoSub, cmdDeprecated)
+	c.AddCommand(cmdPrint, cmdEcho)
+	c.DisableAutoGenTag = true
+	cmdRootWithRun.PersistentFlags().StringVarP(&flags2a, "rootflag", "r", "two", strtwoParentHelp)
+	out := new(bytes.Buffer)
+
+	if err := GenReST(c, out); err != nil {
+		t.Fatal(err)
+	}
+	found := out.String()
+
+	unexpected := "Auto generated"
+	checkStringOmits(t, found, unexpected)
+
+}
+
+func TestGenRSTTree(t *testing.T) {
+	cmd := &cobra.Command{
+		Use: "do [OPTIONS] arg1 arg2",
+	}
+	tmpdir, err := ioutil.TempDir("", "test-gen-rst-tree")
+	if err != nil {
+		t.Fatalf("Failed to create tmpdir: %s", err.Error())
+	}
+	defer os.RemoveAll(tmpdir)
+
+	if err := GenReSTTree(cmd, tmpdir); err != nil {
+		t.Fatalf("GenReSTTree failed: %s", err.Error())
+	}
+
+	if _, err := os.Stat(filepath.Join(tmpdir, "do.rst")); err != nil {
+		t.Fatalf("Expected file 'do.rst' to exist")
+	}
+}
+
+func BenchmarkGenReSTToFile(b *testing.B) {
+	c := initializeWithRootCmd()
+	file, err := ioutil.TempFile("", "")
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer os.Remove(file.Name())
+	defer file.Close()
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if err := GenReST(c, file); err != nil {
+			b.Fatal(err)
+		}
+	}
+}