demo of vault token renewer go routine from internal project

renewer.go

type VaultDriver struct {
	vaultClient *vaultapi.Client
	project     string
}

func (d VaultDriver) TokenRenewer(ctx context.Context) error {
	renewer, err := d.vaultClient.NewRenewer(&vaultapi.RenewerInput{
		Secret: &vaultapi.Secret{
			Auth: &vaultapi.SecretAuth{
				ClientToken:   d.vaultClient.Token(),
				Renewable:     true,
				LeaseDuration: 600,
			},
		},
	})
	if err != nil {
		return errors.Wrap(err, "Unable to start vault token renewer.")
	}

	go renewer.Renew()
	defer renewer.Stop()

	for {
		select {
		case err := <-renewer.DoneCh():
			if err != nil {
				logrus.Errorf("failed to renew vault token: %s", err)
			}
			return errors.Wrap(err, "Vault token renwal failed. Maybe Lease expired?")
		case <-renewer.RenewCh():
			logrus.Info("Successfully renewed vault token")
		case <-ctx.Done():
			return nil
		}
	}
}