Merge pull request #586 from minio/extra-info

Add support for custom help templates.

app.go

@@ -85,6 +85,12 @@ type App struct {
 	ErrWriter io.Writer
 	// Other custom info
 	Metadata map[string]interface{}
+	// Carries a function which returns app specific info.
+	ExtraInfo func() map[string]string
+	// CustomAppHelpTemplate the text template for app help topic.
+	// cli.go uses text/template to render templates. You can
+	// render custom help text by setting this variable.
+	CustomAppHelpTemplate string
 
 	didSetup bool
 }

command.go

@@ -59,6 +59,11 @@ type Command struct {
 	// Full name of command for help, defaults to full command name, including parent commands.
 	HelpName        string
 	commandNamePath []string
+
+	// CustomHelpTemplate the text template for the command help topic.
+	// cli.go uses text/template to render templates. You can
+	// render custom help text by setting this variable.
+	CustomHelpTemplate string
 }
 
 type CommandsByName []Command
@@ -250,6 +255,7 @@ func (c Command) startApp(ctx *Context) error {
 
 	// set CommandNotFound
 	app.CommandNotFound = ctx.App.CommandNotFound
+	app.CustomAppHelpTemplate = c.CustomHelpTemplate
 
 	// set the flags and commands
 	app.Commands = c.Subcommands

help.go

@@ -112,17 +112,42 @@ var helpSubcommand = Command{
 // Prints help for the App or Command
 type helpPrinter func(w io.Writer, templ string, data interface{})
 
+// Prints help for the App or Command with custom template function.
+type helpPrinterCustom func(w io.Writer, templ string, data interface{}, customFunc map[string]interface{})
+
 // HelpPrinter is a function that writes the help output. If not set a default
 // is used. The function signature is:
 // func(w io.Writer, templ string, data interface{})
 var HelpPrinter helpPrinter = printHelp
 
+// HelpPrinterCustom is same as HelpPrinter but
+// takes a custom function for template function map.
+var HelpPrinterCustom helpPrinterCustom = printHelpCustom
+
 // VersionPrinter prints the version for the App
 var VersionPrinter = printVersion
 
+// ShowAppHelpAndExit - Prints the list of subcommands for the app and exits with exit code.
+func ShowAppHelpAndExit(c *Context, exitCode int) {
+	ShowAppHelp(c)
+	os.Exit(exitCode)
+}
+
 // ShowAppHelp is an action that displays the help.
-func ShowAppHelp(c *Context) error {
+func ShowAppHelp(c *Context) (err error) {
+	if c.App.CustomAppHelpTemplate == "" {
 		HelpPrinter(c.App.Writer, AppHelpTemplate, c.App)
+		return
+	}
+	customAppData := func() map[string]interface{} {
+		if c.App.ExtraInfo == nil {
+			return nil
+		}
+		return map[string]interface{}{
+			"ExtraInfo": c.App.ExtraInfo,
+		}
+	}
+	HelpPrinterCustom(c.App.Writer, c.App.CustomAppHelpTemplate, c.App, customAppData())
 	return nil
 }
 
@@ -138,6 +163,12 @@ func DefaultAppComplete(c *Context) {
 	}
 }
 
+// ShowCommandHelpAndExit - exits with code after showing help
+func ShowCommandHelpAndExit(c *Context, command string, code int) {
+	ShowCommandHelp(c, command)
+	os.Exit(code)
+}
+
 // ShowCommandHelp prints help for the given command
 func ShowCommandHelp(ctx *Context, command string) error {
 	// show the subcommand help for a command with subcommands
@@ -148,7 +179,11 @@ func ShowCommandHelp(ctx *Context, command string) error {
 
 	for _, c := range ctx.App.Commands {
 		if c.HasName(command) {
+			if c.CustomHelpTemplate != "" {
+				HelpPrinterCustom(ctx.App.Writer, c.CustomHelpTemplate, c, nil)
+			} else {
 				HelpPrinter(ctx.App.Writer, CommandHelpTemplate, c)
+			}
 			return nil
 		}
 	}
@@ -191,10 +226,15 @@ func ShowCommandCompletions(ctx *Context, command string) {
 	}
 }
 
-func printHelp(out io.Writer, templ string, data interface{}) {
+func printHelpCustom(out io.Writer, templ string, data interface{}, customFunc map[string]interface{}) {
 	funcMap := template.FuncMap{
 		"join": strings.Join,
 	}
+	if customFunc != nil {
+		for key, value := range customFunc {
+			funcMap[key] = value
+		}
+	}
 
 	w := tabwriter.NewWriter(out, 1, 8, 2, ' ', 0)
 	t := template.Must(template.New("help").Funcs(funcMap).Parse(templ))
@@ -210,6 +250,10 @@ func printHelp(out io.Writer, templ string, data interface{}) {
 	w.Flush()
 }
 
+func printHelp(out io.Writer, templ string, data interface{}) {
+	printHelpCustom(out, templ, data, nil)
+}
+
 func checkVersion(c *Context) bool {
 	found := false
 	if VersionFlag.GetName() != "" {

help_test.go

@@ -3,6 +3,8 @@ package cli
 import (
 	"bytes"
 	"flag"
+	"fmt"
+	"runtime"
 	"strings"
 	"testing"
 )
@@ -256,6 +258,49 @@ func TestShowSubcommandHelp_CommandAliases(t *testing.T) {
 	}
 }
 
+func TestShowCommandHelp_Customtemplate(t *testing.T) {
+	app := &App{
+		Commands: []Command{
+			{
+				Name: "frobbly",
+				Action: func(ctx *Context) error {
+					return nil
+				},
+				HelpName: "foo frobbly",
+				CustomHelpTemplate: `NAME:
+   {{.HelpName}} - {{.Usage}}
+
+USAGE:
+   {{.HelpName}} [FLAGS] TARGET [TARGET ...]
+
+FLAGS:
+  {{range .VisibleFlags}}{{.}}
+  {{end}}
+EXAMPLES:
+   1. Frobbly runs with this param locally.
+      $ {{.HelpName}} wobbly
+`,
+			},
+		},
+	}
+
+	output := &bytes.Buffer{}
+	app.Writer = output
+	app.Run([]string{"foo", "help", "frobbly"})
+
+	if strings.Contains(output.String(), "2. Frobbly runs without this param locally.") {
+		t.Errorf("expected output to exclude \"2. Frobbly runs without this param locally.\"; got: %q", output.String())
+	}
+
+	if !strings.Contains(output.String(), "1. Frobbly runs with this param locally.") {
+		t.Errorf("expected output to include \"1. Frobbly runs with this param locally.\"; got: %q", output.String())
+	}
+
+	if !strings.Contains(output.String(), "$ foo frobbly wobbly") {
+		t.Errorf("expected output to include \"$ foo frobbly wobbly\"; got: %q", output.String())
+	}
+}
+
 func TestShowAppHelp_HiddenCommand(t *testing.T) {
 	app := &App{
 		Commands: []Command{
@@ -287,3 +332,78 @@ func TestShowAppHelp_HiddenCommand(t *testing.T) {
 		t.Errorf("expected output to include \"frobbly\"; got: %q", output.String())
 	}
 }
+
+func TestShowAppHelp_CustomAppTemplate(t *testing.T) {
+	app := &App{
+		Commands: []Command{
+			{
+				Name: "frobbly",
+				Action: func(ctx *Context) error {
+					return nil
+				},
+			},
+			{
+				Name:   "secretfrob",
+				Hidden: true,
+				Action: func(ctx *Context) error {
+					return nil
+				},
+			},
+		},
+		ExtraInfo: func() map[string]string {
+			platform := fmt.Sprintf("OS: %s | Arch: %s", runtime.GOOS, runtime.GOARCH)
+			goruntime := fmt.Sprintf("Version: %s | CPUs: %d", runtime.Version(), runtime.NumCPU())
+			return map[string]string{
+				"PLATFORM": platform,
+				"RUNTIME":  goruntime,
+			}
+		},
+		CustomAppHelpTemplate: `NAME:
+  {{.Name}} - {{.Usage}}
+
+USAGE:
+  {{.Name}} {{if .VisibleFlags}}[FLAGS] {{end}}COMMAND{{if .VisibleFlags}} [COMMAND FLAGS | -h]{{end}} [ARGUMENTS...]
+
+COMMANDS:
+  {{range .VisibleCommands}}{{join .Names ", "}}{{ "\t" }}{{.Usage}}
+  {{end}}{{if .VisibleFlags}}
+GLOBAL FLAGS:
+  {{range .VisibleFlags}}{{.}}
+  {{end}}{{end}}
+VERSION:
+  2.0.0
+{{"\n"}}{{range $key, $value := ExtraInfo}}
+{{$key}}:
+  {{$value}}
+{{end}}`,
+	}
+
+	output := &bytes.Buffer{}
+	app.Writer = output
+	app.Run([]string{"app", "--help"})
+
+	if strings.Contains(output.String(), "secretfrob") {
+		t.Errorf("expected output to exclude \"secretfrob\"; got: %q", output.String())
+	}
+
+	if !strings.Contains(output.String(), "frobbly") {
+		t.Errorf("expected output to include \"frobbly\"; got: %q", output.String())
+	}
+
+	if !strings.Contains(output.String(), "PLATFORM:") ||
+		!strings.Contains(output.String(), "OS:") ||
+		!strings.Contains(output.String(), "Arch:") {
+		t.Errorf("expected output to include \"PLATFORM:, OS: and Arch:\"; got: %q", output.String())
+	}
+
+	if !strings.Contains(output.String(), "RUNTIME:") ||
+		!strings.Contains(output.String(), "Version:") ||
+		!strings.Contains(output.String(), "CPUs:") {
+		t.Errorf("expected output to include \"RUNTIME:, Version: and CPUs:\"; got: %q", output.String())
+	}
+
+	if !strings.Contains(output.String(), "VERSION:") ||
+		!strings.Contains(output.String(), "2.0.0") {
+		t.Errorf("expected output to include \"VERSION:, 2.0.0\"; got: %q", output.String())
+	}
+}