Golang Command.Usage方法代碼示例

func runCatManifest(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 1 {
		cmd.Usage()
		return 1
	}

	pod, err := getPodFromUUIDString(args[0])
	if err != nil {
		stderr("cat-manifest: problem retrieving pod: %v", err)
		return 1
	}
	defer pod.Close()

	manifest, err := pod.getManifest()
	if err != nil {
		return 1
	}

	var b []byte
	if flagPMPrettyPrint {
		b, err = json.MarshalIndent(manifest, "", "\t")
	} else {
		b, err = json.Marshal(manifest)
	}
	if err != nil {
		stderr("cat-manifest: cannot read the pod manifest: %v", err)
		return 1
	}

	stdout(string(b))
	return 0
}

func runTrust(cmd *cobra.Command, args []string) (exit int) {
	if globalFlags.InsecureSkipVerify {
		// --insecure-skip-verify disable the keystore but we need it for rkt trust
		stderr("--insecure-skip-verify cannot be used with rkt trust")
		return 1
	}

	if flagPrefix == "" && !flagRoot {
		if len(args) != 0 {
			stderr("--root required for non-prefixed (root) keys")
		} else {
			cmd.Usage()
		}
		return 1
	}

	if flagPrefix != "" && flagRoot {
		stderr("--root and --prefix usage mutually exclusive")
		return 1
	}

	ks := getKeystore()
	if ks == nil {
		stderr("could not get the keystore")
		return 1
	}

	// if the user included a scheme with the prefix, error on it
	u, err := url.Parse(flagPrefix)
	if err == nil && u.Scheme != "" {
		stderr("--prefix must not contain a URL scheme, omit %s://", u.Scheme)
		return 1
	}

	pkls := args
	m := &pubkey.Manager{
		InsecureAllowHttp:  flagAllowHTTP,
		TrustKeysFromHttps: globalFlags.TrustKeysFromHttps,
		Ks:                 ks,
		Debug:              globalFlags.Debug,
	}
	if len(pkls) == 0 {
		pkls, err = m.GetPubKeyLocations(flagPrefix)
		if err != nil {
			stderr("Error determining key location: %v", err)
			return 1
		}
	}

	acceptOpt := pubkey.AcceptAsk
	if globalFlags.InsecureSkipVerify {
		acceptOpt = pubkey.AcceptForce
	}
	if err := m.AddKeys(pkls, flagPrefix, acceptOpt, pubkey.OverrideDeny); err != nil {
		stderr("Error adding keys: %v", err)
		return 1
	}

	return 0
}

func runStatus(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 1 {
		cmd.Usage()
		return 1
	}

	p, err := getPodFromUUIDString(args[0])
	if err != nil {
		stderr("Problem retrieving pod: %v", err)
		return 1
	}
	defer p.Close()

	if flagWait {
		if err := p.waitExited(); err != nil {
			stderr("Unable to wait for pod: %v", err)
			return 1
		}
	}

	if err = printStatus(p); err != nil {
		stderr("Unable to print status: %v", err)
		return 1
	}

	return 0
}

func runImageImport(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 2 {
		cmd.Usage()
		return 1
	}

	outFile := args[1]
	ext := filepath.Ext(outFile)
	if ext != schema.ACIExtension {
		stderr("rkt: Extension must be %s (given %s)", schema.ACIExtension, ext)
		return 1
	}

	aciImgPath, err := oci2aciImage(args[0])
	if err != nil {
		stderr("rkt: oci2aci failed: %s", err)
		return 1
	}

	if err = run(exec.Command("mv", aciImgPath, args[1])); err != nil {
		return 1
	}

	return 0
}

func runRm(cmd *cobra.Command, args []string) (exit int) {
	var podUUID *types.UUID
	var err error

	switch {
	case len(args) == 0 && flagUUIDFile != "":
		podUUID, err = readUUIDFromFile(flagUUIDFile)
		if err != nil {
			stderr("Unable to read UUID from file: %v", err)
			return 1
		}

	case len(args) == 1 && flagUUIDFile == "":
		podUUID, err = resolveUUID(args[0])
		if err != nil {
			stderr("Unable to resolve UUID: %v", err)
			return 1
		}
	default:
		cmd.Usage()
		return 1
	}

	p, err := getPod(podUUID)
	if err != nil {
		stderr("Cannot get pod: %v", err)
		return 1
	}

	return removePod(p)
}

func runTrust(cmd *cobra.Command, args []string) (exit int) {
	if flagPrefix == "" && !flagRoot {
		if len(args) != 0 {
			stderr("--root required for non-prefixed (root) keys")
		} else {
			cmd.Usage()
		}
		return 1
	}

	if flagPrefix != "" && flagRoot {
		stderr("--root and --prefix usage mutually exclusive")
		return 1
	}

	// if the user included a scheme with the prefix, error on it
	u, err := url.Parse(flagPrefix)
	if err == nil && u.Scheme != "" {
		stderr("--prefix must not contain a URL scheme, omit %s://", u.Scheme)
		return 1
	}

	pkls, err := getPubKeyLocations(flagPrefix, args)
	if err != nil {
		stderr("Error determining key location: %v", err)
		return 1
	}

	if err := addKeys(pkls, flagPrefix); err != nil {
		stderr("Error adding keys: %v", err)
		return 1
	}

	return 0
}

func runImageImport(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 1 {
		cmd.Usage()
		return 1
	}

	//convert oci bundle to aci image
	aciImage, err := oci2aci.Oci2aciImage(args[0])
	if err != nil {
		fmt.Printf("oci2aci failed: %v", err)
		return 1
	}

	//save aci to rkt store
	s, err := store.NewStore(globalFlags.Dir)
	if err != nil {
		fmt.Printf("cannot open store: %v", err)
		return 1
	}
	aciFile, err := os.Open(aciImage)
	if err != nil {
		fmt.Printf("opening ACI file %s failed: %v", aciImage, err)
		return 1
	}
	key, err := s.WriteACI(aciFile, true)
	if err != nil {
		fmt.Printf("write ACI file failed: %v", err)
		return 1
	}
	fmt.Println(key)
	return 0
}

func runStatus(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 1 {
		cmd.Usage()
		return 1
	}

	podUUID, err := resolveUUID(args[0])
	if err != nil {
		stderr("Unable to resolve UUID: %v", err)
		return 1
	}

	p, err := getPod(podUUID)
	if err != nil {
		stderr("Unable to get pod: %v", err)
		return 1
	}
	defer p.Close()

	if flagWait {
		if err := p.waitExited(); err != nil {
			stderr("Unable to wait for pod: %v", err)
			return 1
		}
	}

	if err = printStatus(p); err != nil {
		stderr("Unable to print status: %v", err)
		return 1
	}

	return 0
}

func runImageCatManifest(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 1 {
		cmd.Usage()
		return 1
	}

	s, err := store.NewStore(globalFlags.Dir)
	if err != nil {
		stderr("image cat-manifest: cannot open store: %v", err)
		return 1
	}

	var key string
	if _, err := types.NewHash(args[0]); err == nil {
		key, err = s.ResolveKey(args[0])
		if err != nil {
			stderr("image cat-manifest: cannot resolve key: %v", err)
			return 1
		}
	} else {
		app, err := discovery.NewAppFromString(args[0])
		if err != nil {
			stderr("image cat-manifest: cannot parse the image name: %v", err)
			return 1
		}
		labels, err := types.LabelsFromMap(app.Labels)
		if err != nil {
			stderr("image cat-manifest: invalid labels in the name: %v", err)
			return 1
		}
		key, err = s.GetACI(app.Name, labels)
		if err != nil {
			stderr("image cat-manifest: cannot find image: %v", err)
			return 1
		}
	}

	manifest, err := s.GetImageManifest(key)
	if err != nil {
		stderr("image cat-manifest: cannot get image manifest: %v", err)
		return 1
	}

	var b []byte
	if flagPrettyPrint {
		b, err = json.MarshalIndent(manifest, "", "\t")
	} else {
		b, err = json.Marshal(manifest)
	}
	if err != nil {
		stderr("image cat-manifest: cannot read the image manifest: %v", err)
		return 1
	}

	stdout(string(b))
	return 0
}

func runEnter(cmd *cobra.Command, args []string) (exit int) {
	if len(args) < 1 {
		cmd.Usage()
		return 1
	}

	p, err := getPodFromUUIDString(args[0])
	if err != nil {
		stderr("Problem problem retrieving pod: %v", err)
		return 1
	}
	defer p.Close()

	if !p.isRunning() {
		stderr("Pod %q isn't currently running", p.uuid)
		return 1
	}

	podPID, err := p.getContainerPID1()
	if err != nil {
		stderr("Unable to determine the pid for pod %q: %v", p.uuid, err)
		return 1
	}

	appName, err := getAppName(p)
	if err != nil {
		stderr("Unable to determine app name: %v", err)
		return 1
	}

	argv, err := getEnterArgv(p, args)
	if err != nil {
		stderr("Enter failed: %v", err)
		return 1
	}

	s, err := store.NewStore(getDataDir())
	if err != nil {
		stderr("Cannot open store: %v", err)
		return 1
	}

	stage1TreeStoreID, err := p.getStage1TreeStoreID()
	if err != nil {
		stderr("Error getting stage1 treeStoreID: %v", err)
		return 1
	}

	stage1RootFS := s.GetTreeStoreRootFS(stage1TreeStoreID)

	if err = stage0.Enter(p.path(), podPID, *appName, stage1RootFS, argv); err != nil {
		stderr("Enter failed: %v", err)
		return 1
	}
	// not reached when stage0.Enter execs /enter
	return 0
}

func runImageExport(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 2 {
		cmd.Usage()
		return 1
	}

	s, err := store.NewStore(globalFlags.Dir)
	if err != nil {
		stderr("image export: cannot open store: %v", err)
		return 1
	}

	key, err := getKeyFromAppOrHash(s, args[0])
	if err != nil {
		stderr("image export: %v", err)
		return 1
	}

	aci, err := s.ReadStream(key)
	if err != nil {
		stderr("image export: error reading image: %v", err)
		return 1
	}
	defer aci.Close()

	mode := os.O_CREATE | os.O_WRONLY
	if flagOverwriteACI {
		mode |= os.O_TRUNC
	} else {
		mode |= os.O_EXCL
	}
	f, err := os.OpenFile(args[1], mode, 0644)
	if err != nil {
		if os.IsExist(err) {
			stderr("image export: output ACI file exists (try --overwrite)")
		} else {
			stderr("image export: unable to open output ACI file %s: %v", args[1], err)
		}
		return 1
	}
	defer func() {
		err := f.Close()
		if err != nil {
			stderr("image export: error closing output ACI file: %v", err)
			exit = 1
		}
	}()

	_, err = io.Copy(f, aci)
	if err != nil {
		stderr("image export: error writing to output ACI file: %v", err)
		return 1
	}

	return 0
}

func runRm(cmd *cobra.Command, args []string) (exit int) {
	var podUUID *types.UUID
	var podUUIDs []*types.UUID
	var err error

	switch {
	case len(args) == 0 && flagUUIDFile != "":
		podUUID, err = readUUIDFromFile(flagUUIDFile)
		if err != nil {
			stderr("Unable to read UUID from file: %v", err)
			return 1
		}
		podUUIDs = append(podUUIDs, podUUID)

	case len(args) > 0 && flagUUIDFile == "":
		for _, uuid := range args {
			podUUID, err := resolveUUID(uuid)
			if err != nil {
				stderr("Unable to resolve UUID: %v", err)
			} else {
				podUUIDs = append(podUUIDs, podUUID)
			}
		}

	default:
		cmd.Usage()
		return 1
	}

	ret := 0
	for _, podUUID = range podUUIDs {
		p, err := getPod(podUUID)
		if err != nil {
			ret = 1
			stderr("Cannot get pod: %v", err)
		}

		if removePod(p) {
			stdout("%q", p.uuid)
		} else {
			ret = 1
		}
	}

	if ret == 1 {
		stderr("Failed to remove one or more pods")
	}

	return ret
}

func runTrust(cmd *cobra.Command, args []string) (exit int) {
	if globalFlags.InsecureSkipVerify {
		// --insecure-skip-verify disable the keystore but we need it for rkt trust
		stderr("--insecure-skip-verify cannot be used with rkt trust")
		return 1
	}

	if flagPrefix == "" && !flagRoot {
		if len(args) != 0 {
			stderr("--root required for non-prefixed (root) keys")
		} else {
			cmd.Usage()
		}
		return 1
	}

	if flagPrefix != "" && flagRoot {
		stderr("--root and --prefix usage mutually exclusive")
		return 1
	}

	// if the user included a scheme with the prefix, error on it
	u, err := url.Parse(flagPrefix)
	if err == nil && u.Scheme != "" {
		stderr("--prefix must not contain a URL scheme, omit %s://", u.Scheme)
		return 1
	}

	pkls := args
	if len(pkls) == 0 {
		pkls, err = getPubKeyLocations(flagPrefix, flagAllowHTTP, globalFlags.Debug)
		if err != nil {
			stderr("Error determining key location: %v", err)
			return 1
		}
	}

	// allow override
	if err := addKeys(pkls, flagPrefix, flagAllowHTTP, globalFlags.InsecureSkipVerify, true); err != nil {
		stderr("Error adding keys: %v", err)
		return 1
	}

	return 0
}

func runImageCatManifest(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 1 {
		cmd.Usage()
		return 1
	}

	s, err := store.NewStore(globalFlags.Dir)
	if err != nil {
		stderr("image cat-manifest: cannot open store: %v", err)
		return 1
	}

	key, err := getKeyFromAppOrHash(s, args[0])
	if err != nil {
		stderr("image cat-manifest: %v", err)
		return 1
	}

	manifest, err := s.GetImageManifest(key)
	if err != nil {
		stderr("image cat-manifest: cannot get image manifest: %v", err)
		return 1
	}

	var b []byte
	if flagPrettyPrint {
		b, err = json.MarshalIndent(manifest, "", "\t")
	} else {
		b, err = json.Marshal(manifest)
	}
	if err != nil {
		stderr("image cat-manifest: cannot read the image manifest: %v", err)
		return 1
	}

	stdout(string(b))
	return 0
}

func runImageExtract(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 2 {
		cmd.Usage()
		return 1
	}
	outputDir := args[1]

	s, err := store.NewStore(globalFlags.Dir)
	if err != nil {
		stderr("image extract: cannot open store: %v", err)
		return 1
	}

	key, err := getStoreKeyFromAppOrHash(s, args[0])
	if err != nil {
		stderr("image extract: %v", err)
		return 1
	}

	aci, err := s.ReadStream(key)
	if err != nil {
		stderr("image extract: error reading ACI from the store: %v", err)
		return 1
	}

	// ExtractTar needs an absolute path
	absOutputDir, err := filepath.Abs(outputDir)
	if err != nil {
		stderr("image extract: error converting output to an absolute path: %v", err)
		return 1
	}

	if _, err := os.Stat(absOutputDir); err == nil {
		if !flagExtractOverwrite {
			stderr("image extract: output directory exists (try --overwrite)")
			return 1
		}

		// don't allow the user to delete the root filesystem by mistake
		if absOutputDir == "/" {
			stderr("image extract: this would delete your root filesystem. Refusing.")
			return 1
		}

		if err := os.RemoveAll(absOutputDir); err != nil {
			stderr("image extract: error removing existing output dir: %v", err)
			return 1
		}
	}

	// if the user only asks for the rootfs we extract the image to a temporary
	// directory and then move/copy the rootfs to the output directory, if not
	// we just extract the image to the output directory
	extractDir := absOutputDir
	if flagExtractRootfsOnly {
		rktTmpDir, err := s.TmpDir()
		if err != nil {
			stderr("image extract: error creating rkt temporary directory: %v", err)
			return 1
		}

		tmpDir, err := ioutil.TempDir(rktTmpDir, "rkt-image-extract-")
		if err != nil {
			stderr("image extract: error creating temporary directory: %v", err)
			return 1
		}
		defer os.RemoveAll(tmpDir)

		extractDir = tmpDir
	} else {
		if err := os.MkdirAll(absOutputDir, 0755); err != nil {
			stderr("image extract: error creating output directory: %v", err)
			return 1
		}
	}

	if err := tar.ExtractTar(aci, extractDir, false, uid.NewBlankUidRange(), nil); err != nil {
		stderr("image extract: error extracting ACI: %v", err)
		return 1
	}

	if flagExtractRootfsOnly {
		rootfsDir := filepath.Join(extractDir, "rootfs")
		if err := os.Rename(rootfsDir, absOutputDir); err != nil {
			if e, ok := err.(*os.LinkError); ok && e.Err == syscall.EXDEV {
				// it's on a different device, fall back to copying
				if err := fileutil.CopyTree(rootfsDir, absOutputDir, uid.NewBlankUidRange()); err != nil {
					stderr("image extract: error copying ACI rootfs: %v", err)
					return 1
				}
			} else {
				stderr("image extract: error moving ACI rootfs: %v", err)
				return 1
			}
		}
	}

	return 0
}