go-flags

go-flags is a library that provides pflag.FlagSet objects for cobra commands.

Installation

This package is available through go get:

go get github.com/gildas/go-flags

Usage

EnumFlag

You can use the EnumFlag to define a flag that can only take a set of predefined values:

cmd := &cobra.Command{
    Use: "myapp",
    . . .
}

state := flags.NewEnumFlag("+one", "two", "three")
cmd.Flags().Var(state, "state", "State of the flag")
_ = cmd.RegisterFlagCompletionFunc("state", state.CompletionFunc("state"))

As you can see, the EnumFlag is created with a list of strings that are the only values the flag can take. The RegisterFlagCompletionFunc is used to provide completion for the flag.

The default value is prepended with a +.

Instead of values, you can provided instead a function that will be called to get the list of allowed values:

cmd := &cobra.Command{
    Use: "myapp",
    . . .
}

state := flags.NewEnumFlagWithFunc("one", func(context.Context, *cobra.Command, []string) []string {
    return []string{"one", "two", "three"}
})
cmd.Flags().Var(state, "state", "State of the flag")
_ = cmd.RegisterFlagCompletionFunc("state", state.CompletionFunc("state"))

Note that the default value is not prepended with a + in this case.

EnumSliceFlag

You can use the EnumSliceFlag to define a flag that can only take a set of predefined values:

cmd := &cobra.Command{
    Use: "myapp",
    . . .
}

state := flags.NewEnumSliceFlag("+one", "+two", "three")
cmd.Flags().Var(state, "state", "State of the flag")
_ = cmd.RegisterFlagCompletionFunc("state", state.CompletionFunc("state"))

The default values are prepended with a +.

If all values can be provided with an all value, you can use:

cmd := &cobra.Command{
    Use: "myapp",
    . . .
}

state := flags.NewEnumSliceFlagWithAllAllowed("one", "two", "three")
cmd.Flags().Var(state, "state", "State of the flag")
_ = cmd.RegisterFlagCompletionFunc("state", state.CompletionFunc("state"))

Note that there is no need to add the all value to the list of allowed values.