How to retrieve parent command flag value?

[alebedev80]

There are two commands: main and sub-command. In the main command there is PersistentFlag name.

As i understand there are three options:

• define flag name in the sub-command. But if there are dozen sub-command with same logic which requires a name then code smell
• call parent()... i'm implementing command in a way when it doesn't 'know' anything about parents
• use viper. that's anti-pattern "God object". (btw, please help me integrate viper to a sub-command as dependency but not global object)

From my point of view the method PersistentFlags.Lookup() should recursively search for the value of the flag starting from the current subcommand and moving up through the ancestors until it finds the value or reaches the root.

func recursiveFlagLookup(cmd *cobra.Command, flagName string) (string, error) {
	flag := cmd.PersistentFlags().Lookup(flagName)

	if flag != nil && flag.Value != nil {
		return flag.Value.String(), nil
	}

	if cmd.Parent() != nil {
		return recursiveFlagLookup(cmd.Parent(), flagName)
	}

	return "", fmt.Errorf("flag '%s' not found", flagName)
}

But i'm new in Go and Cobra and maybe already exists nice solution. Please help.