conair.go

package main

import (
	"flag"
	"fmt"
	"os"
	"os/user"
	"text/tabwriter"
)

const (
	cliName        = "conair"
	cliDescription = "conair is a command-line interface to systemd-nspawn containers. much like docker."

	bridge      = "nspawn0"
	destination = "192.168.13.0/24"
	home        = "/var/lib/machines"
	hub         = "http://conair.teemow.com/images"
)

var (
	out           *tabwriter.Writer
	globalFlagset = flag.NewFlagSet(cliName, flag.ExitOnError)

	// top level commands
	commands []*Command

	// flags used by all commands
	globalFlags = struct {
		Debug   bool
		Version bool
	}{}

	projectVersion string
)

type stringSlice []string

func (s *stringSlice) String() string {
	return fmt.Sprintf("%v", *s)
}

func (s *stringSlice) Set(value string) error {
	*s = append(*s, value)
	return nil
}

func init() {
	user, err := user.Current()
	if err != nil {
		fmt.Fprintln(os.Stderr, "Can't find current user. Need to be root.")
		os.Exit(1)
	}

	if user.Uid != "0" {
		fmt.Fprintln(os.Stderr, "Please run conair as root.")
		os.Exit(1)
	}

	globalFlagset.BoolVar(&globalFlags.Debug, "debug", false, "Print out more debug information to stderr")
	globalFlagset.BoolVar(&globalFlags.Version, "version", false, "Print the version and exit")
}

type Command struct {
	Name        string       // Name of the Command and the string to use to invoke it
	Summary     string       // One-sentence summary of what the Command does
	Usage       string       // Usage options/arguments
	Description string       // Detailed description of command
	Flags       flag.FlagSet // Set of flags associated with this command

	Run func(args []string) int // Run a command with the given arguments, return exit status
}

func init() {
	out = new(tabwriter.Writer)
	out.Init(os.Stdout, 0, 8, 1, '\t', 0)
	commands = []*Command{
		cmdAttach,
		cmdInit,
		cmdDestroy,
		cmdPs,
		cmdImages,
		cmdRun,
		cmdStop,
		cmdStart,
		cmdRm,
		cmdRmi,
		cmdCommit,
		cmdStatus,
		cmdBuild,
		cmdPull,
		cmdBootstrap,
		cmdInspect,
		cmdIp,
		cmdSnapshot,
		cmdHelp,
		cmdVersion,
	}
}

func getAllFlags() (flags []*flag.Flag) {
	return getFlags(globalFlagset)
}

func getFlags(flagset *flag.FlagSet) (flags []*flag.Flag) {
	flags = make([]*flag.Flag, 0)
	flagset.VisitAll(func(f *flag.Flag) {
		flags = append(flags, f)
	})
	return
}

func main() {
	globalFlagset.Parse(os.Args[1:])

	var args = globalFlagset.Args()

	if len(args) < 1 {
		args = append(args, "help")
	}

	// deal specially with --version
	if globalFlags.Version {
		args[0] = "version"
	}

	var cmd *Command

	// determine which Command should be run
	for _, c := range commands {
		if c.Name == args[0] {
			cmd = c
			if err := c.Flags.Parse(args[1:]); err != nil {
				fmt.Println(err.Error())
				os.Exit(2)
			}
			break
		}
	}

	if cmd == nil {
		fmt.Printf("%v: unknown subcommand: %q\n", cliName, args[0])
		fmt.Printf("Run '%v help' for usage.\n", cliName)
		os.Exit(2)
	}

	os.Exit(cmd.Run(cmd.Flags.Args()))
}