// parseApps looks through the args for support of per-app argument lists delimited with "--" and "---".
// Between per-app argument lists flags.Parse() is called using the supplied FlagSet.
// Anything not consumed by flags.Parse() and not found to be a per-app argument list is treated as an image.
// allowAppArgs controls whether "--" prefixed per-app arguments will be accepted or not.
func parseApps(al *apps.Apps, args []string, flags *pflag.FlagSet, allowAppArgs bool) error {
nAppsLastAppArgs := al.Count()
// valid args here may either be:
// not-"--"; flags handled by *flags or an image specifier
// "--"; app arguments begin
// "---"; conclude app arguments
// between "--" and "---" pairs anything is permitted.
inAppArgs := false
for i := 0; i < len(args); i++ {
a := args[i]
if inAppArgs {
switch a {
case "---":
// conclude this app's args
inAppArgs = false
default:
// keep appending to this app's args
app := al.Last()
app.Args = append(app.Args, a)
}
} else {
switch a {
case "--":
if !allowAppArgs {
return fmt.Errorf("app arguments unsupported")
}
// begin app's args
inAppArgs = true
// catch some likely mistakes
if nAppsLastAppArgs == al.Count() {
if al.Count() == 0 {
return fmt.Errorf("an image is required before any app arguments")
}
return fmt.Errorf("only one set of app arguments allowed per image")
}
nAppsLastAppArgs = al.Count()
case "---":
// ignore triple dashes since they aren't images
// TODO(vc): I don't think ignoring this is appropriate, probably should error; it implies malformed argv.
// "---" is not an image separator, it's an optional argument list terminator.
// encountering it outside of inAppArgs is likely to be "--" typoed
default:
// consume any potential inter-app flags
if err := flags.Parse(args[i:]); err != nil {
return err
}
nInterFlags := (len(args[i:]) - flags.NArg())
if nInterFlags > 0 {
// XXX(vc): flag.Parse() annoyingly consumes the "--", reclaim it here if necessary
if args[i+nInterFlags-1] == "--" {
nInterFlags--
}
// advance past what flags.Parse() consumed
i += nInterFlags - 1 // - 1 because of i++
} else {
// flags.Parse() didn't want this arg, treat as image
al.Create(a)
}
}
}
}
return al.Validate()
}