// distroLtsSeries returns the latest LTS series, if this information is
// available on this system.
func distroLtsSeries() (string, error) {
out, err := exec.Command("distro-info", "--lts").Output()
if err != nil {
return "", err
}
series := strings.TrimSpace(string(out))
if !charm.IsValidSeries(series) {
return "", fmt.Errorf("not a valid LTS series: %q", series)
}
return series, nil
}
// Implements gnuflag.Value Set.
func (v *seriesValue) Set(s string) error {
if err := v.StringsValue.Set(s); err != nil {
return err
}
for _, name := range *(v.StringsValue) {
if !charm.IsValidSeries(name) {
v.StringsValue = nil
return fmt.Errorf("invalid series name %q", name)
}
}
return nil
}