i18n for sub-commands and flags

[decentral1se]

Related to #1134 but a separate topic. Related: #719 (and maybe #2185)

I'm working on a project where there is a need to translate sub-commands and flags.

So, for example:

var FooCommand = &cobra.Command{
    Use:     gotext.Get("foo [flags]"),
    Aliases: []string{"f"},
    Short:   gotext.Get("Short text"),
    Long:    gotext.Get("Long text")
    // ...
}

func init() {
    FooCommand.Flags().BoolVarP(
        &publish,
        gotext.Get("publish"),
        gotext.Get("p")
        false,
        gotext.Get("publish changes"),
    )
}

So if you had a default en.po:

#: foo.go:4
msgid "foo [flags]"
msgstr ""

And a es.po translation:

#: foo.go:4
msgid "foo [flags]"
msgstr "bar [flags]"

So that users can LANG=en mycli foo / LANG=es mycli bar and run the same sub-command. I assume this would be best considered a sort of command translation alias? Also it should be visible in the help output and flags should be translated. This doesn't work atm.

I understand I can override the help template but I am more unsure about the sub-command name. I'm actually not even sure this is supported or if the command generation is based on the strings? Maybe @Goutte you have some ideas actually re: your work on #2090 and previous experiences.

[decentral1se]

Update: it's possible! The issue is that I need to hook in multiple times to initialise the localisation so that gotext.Get can do it's work (on creating the commands, on updating the help template, etc.). It would be great if we could hook in once and initialize gotext and then it's just done for the rest of the execution.

So, for example, I ended up doing:

func generateFooCommand() *cobra.Command {
    lang.LoadLocale("es") // for example
    var c = &cobra.Command{}
    c.Use = gotext.Get("bar [cmd] [args] [flags]")
    // ...
    return c
}

I was hoping init(){...} would do this but it didn't work that way for reasons unknown.

[decentral1se]

We ended up moving to xgettext-go so we could initialise our gotext.Get call in one place and then have it get picked up everywhere. See here for more. I think this just needs to be documented now, nearly everything is translatable by default with cobra (if you want that) except for more internal stuff which will be covered by #2090