code: func (r *runner) activateExecution() (ok bool, err error) {
  	newToken, err := getRandom(r.c, 128)
  	if err != nil {
  		return false, err
  	}
  
  	_, err = r.dmc.ActivateExecution(r.c, &dm.ActivateExecutionReq{
  		Auth:           r.auth,
  		ExecutionToken: newToken,
  	})
  	if err != nil {
  		logging.WithError(err).Errorf(r.c, "could not activate execution")
  		if grpcutil.Code(err) == codes.Unauthenticated {
  			// means we got retried, so invalidate ExecutionKey and quit peacefully.
  			return false, nil
  		}
  		return false, err
  	}
  	r.auth.Token = newToken
  	logging.Fields{"token": r.auth.Token}.Infof(r.c, "activated execution")
  	return true, nil
  }
docs: // activateExecution is essentially a direct map to ActivateExecution, except
  // that it transforms the runner's `auth` from a needs-activation authentication
  // to an activated one.
  //
  // This returns an OK bool, plus an error. If the bool is true, it means that
  // we're now authenticated. This will never return true with a non-nil error.
  //
  // The return value (false, nil) means the runner should quit peacefully
  // (no-error), and can occur if this execution payload is retried (e.g. by
  // taskqueue).