open-nomad/main.go

package main

import (
	"bytes"
	"fmt"
	"io"
	"os"
	"sort"
	"strings"
	"text/tabwriter"

	"github.com/hashicorp/nomad/version"
	"github.com/mitchellh/cli"
	"github.com/sean-/seed"
)

var (
	// Hidden hides the commands from both help and autocomplete. Commands that
	// users should not be running should be placed here, versus hiding
	// subcommands from the main help, which should be filtered out of the
	// commands above.
	hidden = []string{
		"alloc-status",
		"check",
		"client-config",
		"eval-status",
		"executor",
		"fs",
		"init",
		"inspect",
		"keygen",
		"keyring",
		"logs",
		"node-drain",
		"node-status",
		"plan",
		"server-force-leave",
		"server-join",
		"server-members",
		"syslog",
		"validate",
	}

	// Common commands are grouped separately to call them out to operators.
	commonCommands = []string{
		"run",
		"stop",
		"status",
		"alloc",
		"job",
		"node",
		"agent",
	}
)

func init() {
	seed.Init()
}

func main() {
	os.Exit(Run(os.Args[1:]))
}

func Run(args []string) int {
	return RunCustom(args, Commands(nil))
}

func RunCustom(args []string, commands map[string]cli.CommandFactory) int {
	// Build the commands to include in the help now.
	commandsInclude := make([]string, 0, len(commands))
	for k := range commands {
		commandsInclude = append(commandsInclude, k)
	}

	cli := &cli.CLI{
		Name:                       "nomad",
		Version:                    version.GetVersion().FullVersionNumber(true),
		Args:                       args,
		Commands:                   commands,
		HiddenCommands:             hidden,
		Autocomplete:               true,
		AutocompleteNoDefaultFlags: true,
		HelpFunc: groupedHelpFunc(
			cli.BasicHelpFunc("nomad"),
		),
	}

	exitCode, err := cli.Run()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error executing CLI: %s\n", err.Error())
		return 1
	}

	return exitCode
}

// helpFunc is a custom help function. At the moment it is essentially a copy of
// the cli.BasicHelpFunc that includes flags demonstrating how to use the
// autocomplete flags.
func helpFunc(commands map[string]cli.CommandFactory) string {
	var buf bytes.Buffer
	buf.WriteString("Usage: nomad [-version] [-help] [-autocomplete-(un)install] <command> [<args>]\n\n")
	buf.WriteString("Available commands are:\n")

	// Get the list of keys so we can sort them, and also get the maximum
	// key length so they can be aligned properly.
	keys := make([]string, 0, len(commands))
	maxKeyLen := 0
	for key := range commands {
		if len(key) > maxKeyLen {
			maxKeyLen = len(key)
		}

		keys = append(keys, key)
	}
	sort.Strings(keys)

	for _, key := range keys {
		commandFunc, ok := commands[key]
		if !ok {
			// This should never happen since we JUST built the list of
			// keys.
			panic("command not found: " + key)
		}

		command, err := commandFunc()
		if err != nil {
			fmt.Fprintf(os.Stderr, "[ERR] cli: Command '%s' failed to load: %s", key, err)
			continue
		}

		key = fmt.Sprintf("%s%s", key, strings.Repeat(" ", maxKeyLen-len(key)))
		buf.WriteString(fmt.Sprintf("    %s    %s\n", key, command.Synopsis()))
	}

	return buf.String()
}

func groupedHelpFunc(f cli.HelpFunc) cli.HelpFunc {
	return func(commands map[string]cli.CommandFactory) string {
		var b bytes.Buffer
		tw := tabwriter.NewWriter(&b, 0, 2, 6, ' ', 0)

		fmt.Fprintf(tw, "Usage: nomad [-version] [-help] [-autocomplete-(un)install] <command> [args]\n\n")
		fmt.Fprintf(tw, "Common commands:\n")
		for _, v := range commonCommands {
			printCommand(tw, v, commands[v])
		}

		otherCommands := make([]string, 0, len(commands))
		for k := range commands {
			found := false
			for _, v := range commonCommands {
				if k == v {
					found = true
					break
				}
			}

			if !found {
				otherCommands = append(otherCommands, k)
			}
		}
		sort.Strings(otherCommands)

		fmt.Fprintf(tw, "\n")
		fmt.Fprintf(tw, "Other commands:\n")
		for _, v := range otherCommands {
			printCommand(tw, v, commands[v])
		}

		tw.Flush()

		return strings.TrimSpace(b.String())
	}
}

func printCommand(w io.Writer, name string, cmdFn cli.CommandFactory) {
	cmd, err := cmdFn()
	if err != nil {
		panic(fmt.Sprintf("failed to load %q command: %s", name, err))
	}
	fmt.Fprintf(w, "    %s\t%s\n", name, cmd.Synopsis())
}