// EnsureNotBootstrapped returns nil if the environment is not
// bootstrapped, and an error if it is or if the function was not able
// to tell.
func EnsureNotBootstrapped(env environs.Environ) error {
_, err := env.ControllerInstances()
// If there is no error determining controller instaces,
// then we are bootstrapped.
switch errors.Cause(err) {
case nil:
return environs.ErrAlreadyBootstrapped
case environs.ErrNoInstances:
// TODO(axw) 2015-02-03 #1417526
// We should not be relying on this result,
// as it is possible for there to be no
// controllers despite the environment
// being bootstrapped.
fallthrough
case environs.ErrNotBootstrapped:
return nil
}
return err
}