func newRootCmd()

in cmd/root.go [35:111]
70 lines of code
12 McCabe index (conditional complexity)

func newRootCmd(m mountFn) (*cobra.Command, error) {
	var (
		configObj cfg.Config
		cfgFile   string
		cfgErr    error
		v         = viper.New()
	)
	rootCmd := &cobra.Command{
		Use:   "gcsfuse [flags] bucket mount_point",
		Short: "Mount a specified GCS bucket or all accessible buckets locally",
		Long: `Cloud Storage FUSE is an open source FUSE adapter that lets you mount 
and access Cloud Storage buckets as local file systems. For a technical overview
of Cloud Storage FUSE, see https://cloud.google.com/storage/docs/gcs-fuse.`,
		Version:      common.GetVersion(),
		Args:         cobra.RangeArgs(2, 3),
		SilenceUsage: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			if cfgErr != nil {
				return fmt.Errorf("error while parsing config: %w", cfgErr)
			}
			bucket, mountPoint, err := populateArgs(args[1:])
			if err != nil {
				return fmt.Errorf("error occurred while extracting the bucket and mountPoint: %w", err)
			}
			return m(&configObj, bucket, mountPoint)
		},
	}
	initConfig := func() {
		if cfgFile != "" {
			cfgFile, err := util.GetResolvedPath(cfgFile)
			if err != nil {
				cfgErr = fmt.Errorf("error while resolving config-file path[%s]: %w", cfgFile, err)
				return
			}
			v.SetConfigFile(cfgFile)
			v.SetConfigType("yaml")
			if err := v.ReadInConfig(); err != nil {
				cfgErr = fmt.Errorf("error while reading the config: %w", err)
				return
			}
		}

		if cfgErr = v.Unmarshal(&configObj, viper.DecodeHook(cfg.DecodeHook()), func(decoderConfig *mapstructure.DecoderConfig) {
			// By default, viper supports mapstructure tags for unmarshalling. Override that to support yaml tag.
			decoderConfig.TagName = "yaml"
			// Reject the config file if any of the fields in the YAML don't map to the struct.
			decoderConfig.ErrorUnused = true
		},
		); cfgErr != nil {
			return
		}
		if cfgErr = cfg.ValidateConfig(v, &configObj); cfgErr != nil {
			return
		}

		var optimizedFlags []string
		if optimizedFlags, cfgErr = cfg.Optimize(&configObj, v); cfgErr != nil {
			return
		}

		if cfgErr = cfg.Rationalize(v, &configObj, optimizedFlags); cfgErr != nil {
			return
		}
	}
	cobra.OnInitialize(initConfig)
	rootCmd.PersistentFlags().StringVar(&cfgFile, cfg.ConfigFileFlagName, "", "The path to the config file where all gcsfuse related config needs to be specified. "+
		"Refer to 'https://cloud.google.com/storage/docs/gcsfuse-cli#config-file' for possible configurations.")

	// Add all the other flags.
	if err := cfg.BuildFlagSet(rootCmd.PersistentFlags()); err != nil {
		return nil, fmt.Errorf("error while declaring flags: %w", err)
	}
	if err := cfg.BindFlags(v, rootCmd.PersistentFlags()); err != nil {
		return nil, fmt.Errorf("error while binding flags: %w", err)
	}
	return rootCmd, nil
}