rootCAs    *x509.CertPool
	username   string
	password   string
}

// OperatorOption - functional options pattern style for OperatorDNS
type OperatorOption func(*OperatorDNS)

// Authentication - custom username and password for authenticating at the endpoint
func Authentication(username, password string) OperatorOption {
	return func(args *OperatorDNS) {
		args.username = username
		args.password = password
	}

	if n.ClientCert != "" && n.ClientKey == "" || n.ClientCert == "" && n.ClientKey != "" {
		return errors.New("cert and key must be specified as a pair")
	}

	if n.Username != "" && n.Password == "" || n.Username == "" && n.Password != "" {
		return errors.New("username and password must be specified as a pair")
	}

	if n.Streaming.Enable {
		if n.Streaming.ClusterID == "" {
			return errors.New("empty cluster id")
		}
	}

// factory receiver.  This constructor will normalize the username, password
// and authzID via the SASLprep algorithm, as recommended by RFC-5802.  If
// SASLprep fails, the method returns an error.
func (x *XDGSCRAMClient) Begin(userName, password, authzID string) (err error) {
	x.Client, err = x.HashGeneratorFcn.NewClient(userName, password, authzID)
	if err != nil {
		return err
	}

	flag.StringVar(&minioUsername, "u", "", "MinIO Username")
	flag.StringVar(&minioPassword, "p", "", "MinIO Password")
	flag.BoolVar(&displayCreds, "d", false, "Only show generated credentials")
	flag.DurationVar(&expiryDuration, "e", 0, "Request a duration of validity for the generated credential")
	flag.StringVar(&bucketToList, "b", "", "Bucket to list (defaults to username)")

	oeConfig DiscoveryDoc
	client   http.Client
	adminURL string
	realm    string

	// internal value refreshed
	accessToken Token
}

// LoginWithUser authenticates username/password, not needed for Keycloak
func (k *KeycloakProvider) LoginWithUser(username, password string) error {
	return ErrNotImplemented
}

// LoginWithClientID is implemented by Keycloak service account support

	KafkaQueueLimit       = "queue_limit"
	KafkaTLS              = "tls"
	KafkaTLSSkipVerify    = "tls_skip_verify"
	KafkaTLSClientAuth    = "tls_client_auth"
	KafkaSASL             = "sasl"
	KafkaSASLUsername     = "sasl_username"
	KafkaSASLPassword     = "sasl_password"
	KafkaSASLMechanism    = "sasl_mechanism"
	KafkaClientTLSCert    = "client_tls_cert"
	KafkaClientTLSKey     = "client_tls_key"
	KafkaVersion          = "version"

	currTime := UTCNow()

	var (
		username = cred.AccessKey
		claims   = cred.Claims
		groups   = cred.Groups
	)

	if cred.IsTemp() || cred.IsServiceAccount() {
		// For derived credentials, check the parent user's permissions.
		username = cred.ParentUser
	}

	principalType := "Anonymous"
	if username != "" {
		principalType = "User"
		if len(claims) > 0 {

			return errors.New("format value unrecognized")
		}
	}
	if a.Index == "" {
		return errors.New("empty index value")
	}

	if (a.Username == "" && a.Password != "") || (a.Username != "" && a.Password == "") {
		return errors.New("username and password should be set in pairs")
	}

	return nil
}

// ElasticsearchTarget - Elasticsearch target.
type ElasticsearchTarget struct {

	KafkaTopic         = "topic"
	KafkaTLS           = "tls"
	KafkaTLSSkipVerify = "tls_skip_verify"
	KafkaTLSClientAuth = "tls_client_auth"
	KafkaSASL          = "sasl"
	KafkaSASLUsername  = "sasl_username"
	KafkaSASLPassword  = "sasl_password"
	KafkaSASLMechanism = "sasl_mechanism"
	KafkaClientTLSCert = "client_tls_cert"
	KafkaClientTLSKey  = "client_tls_key"
	KafkaVersion       = "version"

	EnvLookupBindDN       = "MINIO_IDENTITY_LDAP_LOOKUP_BIND_DN"
	EnvLookupBindPassword = "MINIO_IDENTITY_LDAP_LOOKUP_BIND_PASSWORD"
)

var removedKeys = []string{
	"sts_expiry",
	"username_format",
	"username_search_filter",
	"username_search_base_dn",
	"group_name_attribute",
}

// DefaultKVS - default config for LDAP config
var (
	DefaultKVS = config.KVS{
		config.KV{
			Key:   config.Enable,
			Value: "",