github.com/containerd/nerdctl@v1.7.7/cmd/nerdctl/main.go

/*
   Copyright The containerd Authors.

   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 main

import (
	"errors"
	"fmt"
	"os"
	"runtime"
	"strconv"
	"strings"
	"time"

	"github.com/containerd/log"
	"github.com/containerd/nerdctl/pkg/config"
	ncdefaults "github.com/containerd/nerdctl/pkg/defaults"
	"github.com/containerd/nerdctl/pkg/errutil"
	"github.com/containerd/nerdctl/pkg/logging"
	"github.com/containerd/nerdctl/pkg/rootlessutil"
	"github.com/containerd/nerdctl/pkg/version"
	"github.com/fatih/color"
	"github.com/pelletier/go-toml/v2"

	"github.com/spf13/cobra"
	"github.com/spf13/pflag"
)

const (
	Category   = "category"
	Management = "management"
)

var (
	// To print Bold Text
	Bold = color.New(color.Bold).SprintfFunc()
)

// usage was derived from https://github.com/spf13/cobra/blob/v1.2.1/command.go#L491-L514
func usage(c *cobra.Command) error {
	s := "Usage: "
	if c.Runnable() {
		s += c.UseLine() + "\n"
	} else {
		s += c.CommandPath() + " [command]\n"
	}
	s += "\n"
	if len(c.Aliases) > 0 {
		s += "Aliases: " + c.NameAndAliases() + "\n"
	}
	if c.HasExample() {
		s += "Example:\n"
		s += c.Example + "\n"
	}

	var managementCommands, nonManagementCommands []*cobra.Command
	for _, f := range c.Commands() {
		f := f
		if f.Hidden {
			continue
		}
		if f.Annotations[Category] == Management {
			managementCommands = append(managementCommands, f)
		} else {
			nonManagementCommands = append(nonManagementCommands, f)
		}
	}
	printCommands := func(title string, commands []*cobra.Command) string {
		if len(commands) == 0 {
			return ""
		}
		var longest int
		for _, f := range commands {
			if l := len(f.Name()); l > longest {
				longest = l
			}
		}

		title = Bold(title)
		t := title + ":\n"
		for _, f := range commands {
			t += "  "
			t += f.Name()
			t += strings.Repeat(" ", longest-len(f.Name()))
			t += "  " + f.Short + "\n"
		}
		t += "\n"
		return t
	}
	s += printCommands("Management commands", managementCommands)
	s += printCommands("Commands", nonManagementCommands)

	s += Bold("Flags") + ":\n"
	s += c.LocalFlags().FlagUsages() + "\n"

	if c == c.Root() {
		s += "Run '" + c.CommandPath() + " COMMAND --help' for more information on a command.\n"
	} else {
		s += "See also '" + c.Root().CommandPath() + " --help' for the global flags such as '--namespace', '--snapshotter', and '--cgroup-manager'."
	}
	fmt.Fprintln(c.OutOrStdout(), s)
	return nil
}

func main() {
	if err := xmain(); err != nil {
		errutil.HandleExitCoder(err)
		log.L.Fatal(err)
	}
}

func xmain() error {
	if len(os.Args) == 3 && os.Args[1] == logging.MagicArgv1 {
		// containerd runtime v2 logging plugin mode.
		// "binary://BIN?KEY=VALUE" URI is parsed into Args {BIN, KEY, VALUE}.
		return logging.Main(os.Args[2])
	}
	// nerdctl CLI mode
	app, err := newApp()
	if err != nil {
		return err
	}
	return app.Execute()
}

func initRootCmdFlags(rootCmd *cobra.Command, tomlPath string) (*pflag.FlagSet, error) {
	cfg := config.New()
	if r, err := os.Open(tomlPath); err == nil {
		log.L.Debugf("Loading config from %q", tomlPath)
		defer r.Close()
		dec := toml.NewDecoder(r).DisallowUnknownFields() // set Strict to detect typo
		if err := dec.Decode(cfg); err != nil {
			return nil, fmt.Errorf("failed to load nerdctl config (not daemon config) from %q (Hint: don't mix up daemon's `config.toml` with `nerdctl.toml`): %w", tomlPath, err)
		}
		log.L.Debugf("Loaded config %+v", cfg)
	} else {
		log.L.WithError(err).Debugf("Not loading config from %q", tomlPath)
		if !errors.Is(err, os.ErrNotExist) {
			return nil, err
		}
	}
	aliasToBeInherited := pflag.NewFlagSet(rootCmd.Name(), pflag.ExitOnError)

	rootCmd.PersistentFlags().Bool("debug", cfg.Debug, "debug mode")
	rootCmd.PersistentFlags().Bool("debug-full", cfg.DebugFull, "debug mode (with full output)")
	// -a is aliases (conflicts with nerdctl images -a)
	AddPersistentStringFlag(rootCmd, "address", []string{"a", "H"}, nil, []string{"host"}, aliasToBeInherited, cfg.Address, "CONTAINERD_ADDRESS", `containerd address, optionally with "unix://" prefix`)
	// -n is aliases (conflicts with nerdctl logs -n)
	AddPersistentStringFlag(rootCmd, "namespace", []string{"n"}, nil, nil, aliasToBeInherited, cfg.Namespace, "CONTAINERD_NAMESPACE", `containerd namespace, such as "moby" for Docker, "k8s.io" for Kubernetes`)
	rootCmd.RegisterFlagCompletionFunc("namespace", shellCompleteNamespaceNames)
	AddPersistentStringFlag(rootCmd, "snapshotter", nil, nil, []string{"storage-driver"}, aliasToBeInherited, cfg.Snapshotter, "CONTAINERD_SNAPSHOTTER", "containerd snapshotter")
	rootCmd.RegisterFlagCompletionFunc("snapshotter", shellCompleteSnapshotterNames)
	rootCmd.RegisterFlagCompletionFunc("storage-driver", shellCompleteSnapshotterNames)
	AddPersistentStringFlag(rootCmd, "cni-path", nil, nil, nil, aliasToBeInherited, cfg.CNIPath, "CNI_PATH", "cni plugins binary directory")
	AddPersistentStringFlag(rootCmd, "cni-netconfpath", nil, nil, nil, aliasToBeInherited, cfg.CNINetConfPath, "NETCONFPATH", "cni config directory")
	rootCmd.PersistentFlags().String("data-root", cfg.DataRoot, "Root directory of persistent nerdctl state (managed by nerdctl, not by containerd)")
	rootCmd.PersistentFlags().String("cgroup-manager", cfg.CgroupManager, `Cgroup manager to use ("cgroupfs"|"systemd")`)
	rootCmd.RegisterFlagCompletionFunc("cgroup-manager", shellCompleteCgroupManagerNames)
	rootCmd.PersistentFlags().Bool("insecure-registry", cfg.InsecureRegistry, "skips verifying HTTPS certs, and allows falling back to plain HTTP")
	// hosts-dir is defined as StringSlice, not StringArray, to allow specifying "--hosts-dir=/etc/containerd/certs.d,/etc/docker/certs.d"
	rootCmd.PersistentFlags().StringSlice("hosts-dir", cfg.HostsDir, "A directory that contains <HOST:PORT>/hosts.toml (containerd style) or <HOST:PORT>/{ca.cert, cert.pem, key.pem} (docker style)")
	// Experimental enable experimental feature, see in https://github.com/containerd/nerdctl/blob/main/docs/experimental.md
	AddPersistentBoolFlag(rootCmd, "experimental", nil, nil, cfg.Experimental, "NERDCTL_EXPERIMENTAL", "Control experimental: https://github.com/containerd/nerdctl/blob/main/docs/experimental.md")
	AddPersistentStringFlag(rootCmd, "host-gateway-ip", nil, nil, nil, aliasToBeInherited, cfg.HostGatewayIP, "NERDCTL_HOST_GATEWAY_IP", "IP address that the special 'host-gateway' string in --add-host resolves to. Defaults to the IP address of the host. It has no effect without setting --add-host")
	return aliasToBeInherited, nil
}

func newApp() (*cobra.Command, error) {

	tomlPath := ncdefaults.NerdctlTOML()
	if v, ok := os.LookupEnv("NERDCTL_TOML"); ok {
		tomlPath = v
	}

	short := "nerdctl is a command line interface for containerd"
	long := fmt.Sprintf(`%s

Config file ($NERDCTL_TOML): %s
`, short, tomlPath)
	var rootCmd = &cobra.Command{
		Use:              "nerdctl",
		Short:            short,
		Long:             long,
		Version:          strings.TrimPrefix(version.GetVersion(), "v"),
		SilenceUsage:     true,
		SilenceErrors:    true,
		TraverseChildren: true, // required for global short hands like -a, -H, -n
	}

	rootCmd.SetUsageFunc(usage)
	aliasToBeInherited, err := initRootCmdFlags(rootCmd, tomlPath)
	if err != nil {
		return nil, err
	}

	rootCmd.PersistentPreRunE = func(cmd *cobra.Command, args []string) error {
		globalOptions, err := processRootCmdFlags(cmd)
		if err != nil {
			return err
		}
		debug := globalOptions.DebugFull
		if !debug {
			debug = globalOptions.Debug
		}
		if debug {
			log.SetLevel(log.DebugLevel.String())
		}
		address := globalOptions.Address
		if strings.Contains(address, "://") && !strings.HasPrefix(address, "unix://") {
			return fmt.Errorf("invalid address %q", address)
		}
		cgroupManager := globalOptions.CgroupManager
		if runtime.GOOS == "linux" {
			switch cgroupManager {
			case "systemd", "cgroupfs", "none":
			default:
				return fmt.Errorf("invalid cgroup-manager %q (supported values: \"systemd\", \"cgroupfs\", \"none\")", cgroupManager)
			}
		}
		if appNeedsRootlessParentMain(cmd, args) {
			// reexec /proc/self/exe with `nsenter` into RootlessKit namespaces
			return rootlessutil.ParentMain(globalOptions.HostGatewayIP)
		}
		return nil
	}
	rootCmd.RunE = unknownSubcommandAction
	rootCmd.AddCommand(
		newCreateCommand(),
		// #region Run & Exec
		newRunCommand(),
		newUpdateCommand(),
		newExecCommand(),
		// #endregion

		// #region Container management
		newPsCommand(),
		newLogsCommand(),
		newPortCommand(),
		newStopCommand(),
		newStartCommand(),
		newDiffCommand(),
		newRestartCommand(),
		newKillCommand(),
		newRmCommand(),
		newPauseCommand(),
		newUnpauseCommand(),
		newCommitCommand(),
		newWaitCommand(),
		newRenameCommand(),
		newAttachCommand(),
		// #endregion

		// Build
		newBuildCommand(),

		// #region Image management
		newImagesCommand(),
		newPullCommand(),
		newPushCommand(),
		newLoadCommand(),
		newSaveCommand(),
		newTagCommand(),
		newRmiCommand(),
		newHistoryCommand(),
		// #endregion

		// #region System
		newEventsCommand(),
		newInfoCommand(),
		newVersionCommand(),
		// #endregion

		// Inspect
		newInspectCommand(),

		// stats
		newTopCommand(),
		newStatsCommand(),

		// #region Management
		newContainerCommand(),
		newImageCommand(),
		newNetworkCommand(),
		newVolumeCommand(),
		newSystemCommand(),
		newNamespaceCommand(),
		newBuilderCommand(),
		// #endregion

		// Internal
		newInternalCommand(),

		// login
		newLoginCommand(),

		// Logout
		newLogoutCommand(),

		// Compose
		newComposeCommand(),

		// IPFS
		newIPFSCommand(),
	)
	addApparmorCommand(rootCmd)
	addCpCommand(rootCmd)

	// add aliasToBeInherited to subCommand(s) InheritedFlags
	for _, subCmd := range rootCmd.Commands() {
		subCmd.InheritedFlags().AddFlagSet(aliasToBeInherited)
	}
	return rootCmd, nil
}

func globalFlags(cmd *cobra.Command) (string, []string) {
	args0, err := os.Executable()
	if err != nil {
		log.L.WithError(err).Warnf("cannot call os.Executable(), assuming the executable to be %q", os.Args[0])
		args0 = os.Args[0]
	}
	if len(os.Args) < 2 {
		return args0, nil
	}

	rootCmd := cmd.Root()
	flagSet := rootCmd.Flags()
	args := []string{}
	flagSet.VisitAll(func(f *pflag.Flag) {
		key := f.Name
		val := f.Value.String()
		if f.Changed {
			args = append(args, "--"+key+"="+val)
		}
	})
	return args0, args
}

// unknownSubcommandAction is needed to let `nerdctl system non-existent-command` fail
// https://github.com/containerd/nerdctl/issues/487
//
// Ideally this should be implemented in Cobra itself.
func unknownSubcommandAction(cmd *cobra.Command, args []string) error {
	if len(args) == 0 {
		return cmd.Help()
	}
	// The output mimics https://github.com/spf13/cobra/blob/v1.2.1/command.go#L647-L662
	msg := fmt.Sprintf("unknown subcommand %q for %q", args[0], cmd.Name())
	if suggestions := cmd.SuggestionsFor(args[0]); len(suggestions) > 0 {
		msg += "\n\nDid you mean this?\n"
		for _, s := range suggestions {
			msg += fmt.Sprintf("\t%v\n", s)
		}
	}
	return errors.New(msg)
}

// AddStringFlag is similar to cmd.Flags().String but supports aliases and env var
func AddStringFlag(cmd *cobra.Command, name string, aliases []string, value string, env, usage string) {
	if env != "" {
		usage = fmt.Sprintf("%s [$%s]", usage, env)
	}
	if envV, ok := os.LookupEnv(env); ok {
		value = envV
	}
	aliasesUsage := fmt.Sprintf("Alias of --%s", name)
	p := new(string)
	flags := cmd.Flags()
	flags.StringVar(p, name, value, usage)
	for _, a := range aliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			flags.StringVarP(p, a, a, value, aliasesUsage)
		} else {
			flags.StringVar(p, a, value, aliasesUsage)
		}
	}
}

// AddIntFlag is similar to cmd.Flags().Int but supports aliases and env var
func AddIntFlag(cmd *cobra.Command, name string, aliases []string, value int, env, usage string) {
	if env != "" {
		usage = fmt.Sprintf("%s [$%s]", usage, env)
	}
	if envV, ok := os.LookupEnv(env); ok {
		v, err := strconv.ParseInt(envV, 10, 64)
		if err != nil {
			log.L.WithError(err).Warnf("Invalid int value for `%s`", env)
		}
		value = int(v)
	}
	aliasesUsage := fmt.Sprintf("Alias of --%s", name)
	p := new(int)
	flags := cmd.Flags()
	flags.IntVar(p, name, value, usage)
	for _, a := range aliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			flags.IntVarP(p, a, a, value, aliasesUsage)
		} else {
			flags.IntVar(p, a, value, aliasesUsage)
		}
	}
}

// AddDurationFlag is similar to cmd.Flags().Duration but supports aliases and env var
func AddDurationFlag(cmd *cobra.Command, name string, aliases []string, value time.Duration, env, usage string) {
	if env != "" {
		usage = fmt.Sprintf("%s [$%s]", usage, env)
	}
	if envV, ok := os.LookupEnv(env); ok {
		var err error
		value, err = time.ParseDuration(envV)
		if err != nil {
			log.L.WithError(err).Warnf("Invalid duration value for `%s`", env)
		}
	}
	aliasesUsage := fmt.Sprintf("Alias of --%s", name)
	p := new(time.Duration)
	flags := cmd.Flags()
	flags.DurationVar(p, name, value, usage)
	for _, a := range aliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			flags.DurationVarP(p, a, a, value, aliasesUsage)
		} else {
			flags.DurationVar(p, a, value, aliasesUsage)
		}
	}
}

// AddPersistentStringFlag is similar to AddStringFlag but persistent.
// See https://github.com/spf13/cobra/blob/main/user_guide.md#persistent-flags to learn what is "persistent".
func AddPersistentStringFlag(cmd *cobra.Command, name string, aliases, localAliases, persistentAliases []string, aliasToBeInherited *pflag.FlagSet, value string, env, usage string) {
	if env != "" {
		usage = fmt.Sprintf("%s [$%s]", usage, env)
	}
	if envV, ok := os.LookupEnv(env); ok {
		value = envV
	}
	aliasesUsage := fmt.Sprintf("Alias of --%s", name)
	p := new(string)

	// flags is full set of flag(s)
	// flags can redefine alias already used in subcommands
	flags := cmd.Flags()
	for _, a := range aliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			flags.StringVarP(p, a, a, value, aliasesUsage)
		} else {
			flags.StringVar(p, a, value, aliasesUsage)
		}
		// non-persistent flags are not added to the InheritedFlags, so we should add them manually
		f := flags.Lookup(a)
		aliasToBeInherited.AddFlag(f)
	}

	// localFlags are local to the rootCmd
	localFlags := cmd.LocalFlags()
	for _, a := range localAliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			localFlags.StringVarP(p, a, a, value, aliasesUsage)
		} else {
			localFlags.StringVar(p, a, value, aliasesUsage)
		}
	}

	// persistentFlags cannot redefine alias already used in subcommands
	persistentFlags := cmd.PersistentFlags()
	persistentFlags.StringVar(p, name, value, usage)
	for _, a := range persistentAliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			persistentFlags.StringVarP(p, a, a, value, aliasesUsage)
		} else {
			persistentFlags.StringVar(p, a, value, aliasesUsage)
		}
	}
}

// AddPersistentBoolFlag is similar to AddBoolFlag but persistent.
// See https://github.com/spf13/cobra/blob/main/user_guide.md#persistent-flags to learn what is "persistent".
func AddPersistentBoolFlag(cmd *cobra.Command, name string, aliases, nonPersistentAliases []string, value bool, env, usage string) {
	if env != "" {
		usage = fmt.Sprintf("%s [$%s]", usage, env)
	}
	if envV, ok := os.LookupEnv(env); ok {
		var err error
		value, err = strconv.ParseBool(envV)
		if err != nil {
			log.L.WithError(err).Warnf("Invalid boolean value for `%s`", env)
		}
	}
	aliasesUsage := fmt.Sprintf("Alias of --%s", name)
	p := new(bool)
	flags := cmd.Flags()
	for _, a := range nonPersistentAliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			flags.BoolVarP(p, a, a, value, aliasesUsage)
		} else {
			flags.BoolVar(p, a, value, aliasesUsage)
		}
	}

	persistentFlags := cmd.PersistentFlags()
	persistentFlags.BoolVar(p, name, value, usage)
	for _, a := range aliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			persistentFlags.BoolVarP(p, a, a, value, aliasesUsage)
		} else {
			persistentFlags.BoolVar(p, a, value, aliasesUsage)
		}
	}
}

// AddPersistentStringArrayFlag is similar to cmd.Flags().StringArray but supports aliases and env var and persistent.
// See https://github.com/spf13/cobra/blob/main/user_guide.md#persistent-flags to learn what is "persistent".
func AddPersistentStringArrayFlag(cmd *cobra.Command, name string, aliases, nonPersistentAliases []string, value []string, env string, usage string) {
	if env != "" {
		usage = fmt.Sprintf("%s [$%s]", usage, env)
	}
	if envV, ok := os.LookupEnv(env); ok {
		value = []string{envV}
	}
	aliasesUsage := fmt.Sprintf("Alias of --%s", name)
	p := new([]string)
	flags := cmd.Flags()
	for _, a := range nonPersistentAliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			flags.StringArrayVarP(p, a, a, value, aliasesUsage)
		} else {
			flags.StringArrayVar(p, a, value, aliasesUsage)
		}
	}

	persistentFlags := cmd.PersistentFlags()
	persistentFlags.StringArrayVar(p, name, value, usage)
	for _, a := range aliases {
		if len(a) == 1 {
			// pflag doesn't support short-only flags, so we have to register long one as well here
			persistentFlags.StringArrayVarP(p, a, a, value, aliasesUsage)
		} else {
			persistentFlags.StringArrayVar(p, a, value, aliasesUsage)
		}
	}
}

func checkExperimental(feature string) func(cmd *cobra.Command, args []string) error {
	return func(cmd *cobra.Command, args []string) error {
		globalOptions, err := processRootCmdFlags(cmd)
		if err != nil {
			return err
		}
		if !globalOptions.Experimental {
			return fmt.Errorf("%s is experimental feature, you should enable experimental config", feature)
		}
		return nil
	}
}

// IsExactArgs returns an error if there is not the exact number of args
func IsExactArgs(number int) cobra.PositionalArgs {
	return func(cmd *cobra.Command, args []string) error {
		if len(args) == number {
			return nil
		}
		return fmt.Errorf(
			"%q requires exactly %d %s.\nSee '%s --help'.\n\nUsage:  %s\n\n%s",
			cmd.CommandPath(),
			number,
			"argument(s)",
			cmd.CommandPath(),
			cmd.UseLine(),
			cmd.Short,
		)
	}
}