func RunModule(key string, module Module, args []string, w io.Writer) {
flagSet := flag.NewFlagSet(key, flag.ContinueOnError)
flagSet.Usage = func() {
module.Help(os.Stderr)
flagSet.SetOutput(os.Stderr)
flagSet.PrintDefaults()
}
if adapter, is := module.(*module_adapter); is {
gflag.RegisterFlags(key, adapter.obj, flagSet)
} else {
gflag.RegisterFlags(key, module, flagSet)
}
err := flagSet.Parse(args)
if err != nil {
handle(err, flag.ExitOnError)
} else {
// We make it possible for the module to ask to reparse the flags again.
// This gives us the ablility to layer flags on top of config data after
// config template has been applied to an object.
// We conveniently use function and closures to store copies of the flagSet and args.
reparseLock.Lock()
reparseFlags[reflect.TypeOf(module)] = func() {
// this should be fine here since the first time we parsed ok.
flagSet.Parse(args)
}
reparseLock.Unlock()
policy, has := policies[key]
if !has {
policy = flag.PanicOnError
}
handle(module.Run(flagSet.Args(), w), policy)
handle(module.Close(), policy)
}
}
func showHelp(out io.Writer) {
command.VisitModules(func(v string, module command.Module) {
fmt.Fprintf(out, "%s\n", v)
buff := new(bytes.Buffer)
module.Help(buff)
for _, line := range strings.Split(buff.String(), "\n") {
fmt.Fprintf(out, " %s\n", line)
}
// show flags
fs := flag.NewFlagSet(v, flag.PanicOnError)
cf.RegisterFlags(v, module, fs)
fs.PrintDefaults()
})
}