helm-external-secrets/pkg/provider/vault/vault.go

/*
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package vault

import (
	"bytes"
	"context"
	"crypto/tls"
	"crypto/x509"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"os"
	"strconv"
	"strings"

	"github.com/go-logr/logr"
	vault "github.com/hashicorp/vault/api"
	approle "github.com/hashicorp/vault/api/auth/approle"
	authkubernetes "github.com/hashicorp/vault/api/auth/kubernetes"
	authldap "github.com/hashicorp/vault/api/auth/ldap"
	"github.com/spf13/pflag"
	"github.com/tidwall/gjson"
	authenticationv1 "k8s.io/api/authentication/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/kubernetes"
	typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
	ctrl "sigs.k8s.io/controller-runtime"
	kclient "sigs.k8s.io/controller-runtime/pkg/client"
	ctrlcfg "sigs.k8s.io/controller-runtime/pkg/client/config"

	esv1beta1 "github.com/external-secrets/external-secrets/apis/externalsecrets/v1beta1"
	esmeta "github.com/external-secrets/external-secrets/apis/meta/v1"
	"github.com/external-secrets/external-secrets/pkg/cache"
	"github.com/external-secrets/external-secrets/pkg/feature"
	"github.com/external-secrets/external-secrets/pkg/find"
	"github.com/external-secrets/external-secrets/pkg/provider/metrics"
	"github.com/external-secrets/external-secrets/pkg/utils"
)

var (
	_           esv1beta1.Provider      = &connector{}
	_           esv1beta1.SecretsClient = &client{}
	enableCache bool
	logger      = ctrl.Log.WithName("provider").WithName("vault")
	clientCache *cache.Cache[Client]
)

const (
	serviceAccTokenPath = "/var/run/secrets/kubernetes.io/serviceaccount/token"

	errVaultStore           = "received invalid Vault SecretStore resource: %w"
	errVaultCacheCreate     = "cannot create Vault client cache: %s"
	errVaultCacheRemove     = "error removing item from Vault client cache: %w"
	errVaultCacheEviction   = "unexpected eviction from Vault client cache"
	errVaultClient          = "cannot setup new vault client: %w"
	errVaultCert            = "cannot set Vault CA certificate: %w"
	errReadSecret           = "cannot read secret data from Vault: %w"
	errAuthFormat           = "cannot initialize Vault client: no valid auth method specified"
	errInvalidCredentials   = "invalid vault credentials: %w"
	errDataField            = "failed to find data field"
	errJSONUnmarshall       = "failed to unmarshall JSON"
	errPathInvalid          = "provided Path isn't a valid kv v2 path"
	errSecretFormat         = "secret data not in expected format"
	errUnexpectedKey        = "unexpected key in data: %s"
	errVaultToken           = "cannot parse Vault authentication token: %w"
	errVaultRequest         = "error from Vault request: %w"
	errServiceAccount       = "cannot read Kubernetes service account token from file system: %w"
	errJwtNoTokenSource     = "neither `secretRef` nor `kubernetesServiceAccountToken` was supplied as token source for jwt authentication"
	errUnsupportedKvVersion = "cannot perform find operations with kv version v1"
	errNotFound             = "secret not found"

	errGetKubeSA             = "cannot get Kubernetes service account %q: %w"
	errGetKubeSASecrets      = "cannot find secrets bound to service account: %q"
	errGetKubeSANoToken      = "cannot find token in secrets bound to service account: %q"
	errGetKubeSATokenRequest = "cannot request Kubernetes service account token for service account %q: %w"

	errGetKubeSecret = "cannot get Kubernetes secret %q: %w"
	errSecretKeyFmt  = "cannot find secret data for key: %q"
	errConfigMapFmt  = "cannot find config map data for key: %q"

	errClientTLSAuth = "error from Client TLS Auth: %q"

	errVaultRevokeToken = "error while revoking token: %w"

	errUnknownCAProvider = "unknown caProvider type given"
	errCANamespace       = "cannot read secret for CAProvider due to missing namespace on kind ClusterSecretStore"

	errInvalidStore      = "invalid store"
	errInvalidStoreSpec  = "invalid store spec"
	errInvalidStoreProv  = "invalid store provider"
	errInvalidVaultProv  = "invalid vault provider"
	errInvalidAppRoleSec = "invalid Auth.AppRole.SecretRef: %w"
	errInvalidClientCert = "invalid Auth.Cert.ClientCert: %w"
	errInvalidCertSec    = "invalid Auth.Cert.SecretRef: %w"
	errInvalidJwtSec     = "invalid Auth.Jwt.SecretRef: %w"
	errInvalidJwtK8sSA   = "invalid Auth.Jwt.KubernetesServiceAccountToken.ServiceAccountRef: %w"
	errInvalidKubeSA     = "invalid Auth.Kubernetes.ServiceAccountRef: %w"
	errInvalidKubeSec    = "invalid Auth.Kubernetes.SecretRef: %w"
	errInvalidLdapSec    = "invalid Auth.Ldap.SecretRef: %w"
	errInvalidTokenRef   = "invalid Auth.TokenSecretRef: %w"
)

// https://github.com/external-secrets/external-secrets/issues/644
var _ esv1beta1.SecretsClient = &client{}
var _ esv1beta1.Provider = &connector{}

type Auth interface {
	Login(ctx context.Context, authMethod vault.AuthMethod) (*vault.Secret, error)
}

type Token interface {
	RevokeSelfWithContext(ctx context.Context, token string) error
	LookupSelfWithContext(ctx context.Context) (*vault.Secret, error)
}

type Logical interface {
	ReadWithDataWithContext(ctx context.Context, path string, data map[string][]string) (*vault.Secret, error)
	ListWithContext(ctx context.Context, path string) (*vault.Secret, error)
	WriteWithContext(ctx context.Context, path string, data map[string]interface{}) (*vault.Secret, error)
	DeleteWithContext(ctx context.Context, path string) (*vault.Secret, error)
}

type Client interface {
	SetToken(v string)
	Token() string
	ClearToken()
	Auth() Auth
	Logical() Logical
	AuthToken() Token
	SetNamespace(namespace string)
	AddHeader(key, value string)
}

type VClient struct {
	setToken     func(v string)
	token        func() string
	clearToken   func()
	auth         Auth
	logical      Logical
	authToken    Token
	setNamespace func(namespace string)
	addHeader    func(key, value string)
}

func (v VClient) AddHeader(key, value string) {
	v.addHeader(key, value)
}

func (v VClient) SetNamespace(namespace string) {
	v.setNamespace(namespace)
}

func (v VClient) ClearToken() {
	v.clearToken()
}

func (v VClient) Token() string {
	return v.token()
}

func (v VClient) SetToken(token string) {
	v.setToken(token)
}

func (v VClient) Auth() Auth {
	return v.auth
}

func (v VClient) AuthToken() Token {
	return v.authToken
}

func (v VClient) Logical() Logical {
	return v.logical
}

type client struct {
	kube      kclient.Client
	store     *esv1beta1.VaultProvider
	log       logr.Logger
	corev1    typedcorev1.CoreV1Interface
	client    Client
	auth      Auth
	logical   Logical
	token     Token
	namespace string
	storeKind string
}

func newVaultClient(c *vault.Config) (Client, error) {
	cl, err := vault.NewClient(c)
	if err != nil {
		return nil, err
	}
	auth := cl.Auth()
	logical := cl.Logical()
	token := cl.Auth().Token()
	out := VClient{
		setToken:     cl.SetToken,
		token:        cl.Token,
		clearToken:   cl.ClearToken,
		auth:         auth,
		authToken:    token,
		logical:      logical,
		setNamespace: cl.SetNamespace,
		addHeader:    cl.AddHeader,
	}
	return out, nil
}

func getVaultClient(c *connector, store esv1beta1.GenericStore, cfg *vault.Config) (Client, error) {
	isStaticToken := store.GetSpec().Provider.Vault.Auth.TokenSecretRef != nil
	useCache := enableCache && !isStaticToken

	key := cache.Key{
		Name:      store.GetObjectMeta().Name,
		Namespace: store.GetObjectMeta().Namespace,
		Kind:      store.GetTypeMeta().Kind,
	}
	if useCache {
		client, ok := clientCache.Get(store.GetObjectMeta().ResourceVersion, key)
		if ok {
			return client, nil
		}
	}

	client, err := c.newVaultClient(cfg)
	if err != nil {
		return nil, fmt.Errorf(errVaultClient, err)
	}

	if useCache && !clientCache.Contains(key) {
		clientCache.Add(store.GetObjectMeta().ResourceVersion, key, client)
	}
	return client, nil
}

type connector struct {
	newVaultClient func(c *vault.Config) (Client, error)
}

// Capabilities return the provider supported capabilities (ReadOnly, WriteOnly, ReadWrite).
func (c *connector) Capabilities() esv1beta1.SecretStoreCapabilities {
	return esv1beta1.SecretStoreReadWrite
}

func (c *connector) NewClient(ctx context.Context, store esv1beta1.GenericStore, kube kclient.Client, namespace string) (esv1beta1.SecretsClient, error) {
	// controller-runtime/client does not support TokenRequest or other subresource APIs
	// so we need to construct our own client and use it to fetch tokens
	// (for Kubernetes service account token auth)
	restCfg, err := ctrlcfg.GetConfig()
	if err != nil {
		return nil, err
	}
	clientset, err := kubernetes.NewForConfig(restCfg)
	if err != nil {
		return nil, err
	}

	return c.newClient(ctx, store, kube, clientset.CoreV1(), namespace)
}

func (c *connector) newClient(ctx context.Context, store esv1beta1.GenericStore, kube kclient.Client, corev1 typedcorev1.CoreV1Interface, namespace string) (esv1beta1.SecretsClient, error) {
	storeSpec := store.GetSpec()
	if storeSpec == nil || storeSpec.Provider == nil || storeSpec.Provider.Vault == nil {
		return nil, errors.New(errVaultStore)
	}
	vaultSpec := storeSpec.Provider.Vault

	vStore := &client{
		kube:      kube,
		corev1:    corev1,
		store:     vaultSpec,
		log:       logger,
		namespace: namespace,
		storeKind: store.GetObjectKind().GroupVersionKind().Kind,
	}

	cfg, err := vStore.newConfig()
	if err != nil {
		return nil, err
	}

	client, err := getVaultClient(c, store, cfg)
	if err != nil {
		return nil, fmt.Errorf(errVaultClient, err)
	}

	if vaultSpec.Namespace != nil {
		client.SetNamespace(*vaultSpec.Namespace)
	}

	if vaultSpec.ReadYourWrites && vaultSpec.ForwardInconsistent {
		client.AddHeader("X-Vault-Inconsistent", "forward-active-node")
	}
	vStore.client = client
	vStore.auth = client.Auth()
	vStore.logical = client.Logical()
	vStore.token = client.AuthToken()

	// allow SecretStore controller validation to pass
	// when using referent namespace.
	if vStore.storeKind == esv1beta1.ClusterSecretStoreKind && vStore.namespace == "" && isReferentSpec(vaultSpec) {
		return vStore, nil
	}
	if err := vStore.setAuth(ctx, cfg); err != nil {
		return nil, err
	}

	return vStore, nil
}

func (c *connector) ValidateStore(store esv1beta1.GenericStore) error {
	if store == nil {
		return fmt.Errorf(errInvalidStore)
	}
	spc := store.GetSpec()
	if spc == nil {
		return fmt.Errorf(errInvalidStoreSpec)
	}
	if spc.Provider == nil {
		return fmt.Errorf(errInvalidStoreProv)
	}
	p := spc.Provider.Vault
	if p == nil {
		return fmt.Errorf(errInvalidVaultProv)
	}
	if p.Auth.AppRole != nil {
		if err := utils.ValidateReferentSecretSelector(store, p.Auth.AppRole.SecretRef); err != nil {
			return fmt.Errorf(errInvalidAppRoleSec, err)
		}
	}
	if p.Auth.Cert != nil {
		if err := utils.ValidateReferentSecretSelector(store, p.Auth.Cert.ClientCert); err != nil {
			return fmt.Errorf(errInvalidClientCert, err)
		}
		if err := utils.ValidateReferentSecretSelector(store, p.Auth.Cert.SecretRef); err != nil {
			return fmt.Errorf(errInvalidCertSec, err)
		}
	}
	if p.Auth.Jwt != nil {
		if p.Auth.Jwt.SecretRef != nil {
			if err := utils.ValidateReferentSecretSelector(store, *p.Auth.Jwt.SecretRef); err != nil {
				return fmt.Errorf(errInvalidJwtSec, err)
			}
		} else if p.Auth.Jwt.KubernetesServiceAccountToken != nil {
			if err := utils.ValidateReferentServiceAccountSelector(store, p.Auth.Jwt.KubernetesServiceAccountToken.ServiceAccountRef); err != nil {
				return fmt.Errorf(errInvalidJwtK8sSA, err)
			}
		} else {
			return fmt.Errorf(errJwtNoTokenSource)
		}
	}
	if p.Auth.Kubernetes != nil {
		if p.Auth.Kubernetes.ServiceAccountRef != nil {
			if err := utils.ValidateReferentServiceAccountSelector(store, *p.Auth.Kubernetes.ServiceAccountRef); err != nil {
				return fmt.Errorf(errInvalidKubeSA, err)
			}
		}
		if p.Auth.Kubernetes.SecretRef != nil {
			if err := utils.ValidateReferentSecretSelector(store, *p.Auth.Kubernetes.SecretRef); err != nil {
				return fmt.Errorf(errInvalidKubeSec, err)
			}
		}
	}
	if p.Auth.Ldap != nil {
		if err := utils.ValidateReferentSecretSelector(store, p.Auth.Ldap.SecretRef); err != nil {
			return fmt.Errorf(errInvalidLdapSec, err)
		}
	}
	if p.Auth.TokenSecretRef != nil {
		if err := utils.ValidateReferentSecretSelector(store, *p.Auth.TokenSecretRef); err != nil {
			return fmt.Errorf(errInvalidTokenRef, err)
		}
	}
	return nil
}

func (v *client) DeleteSecret(ctx context.Context, remoteRef esv1beta1.PushRemoteRef) error {
	path := v.buildPath(remoteRef.GetRemoteKey())
	metaPath, err := v.buildMetadataPath(remoteRef.GetRemoteKey())
	if err != nil {
		return err
	}
	// Retrieve the secret map from vault and convert the secret value in string form.
	_, err = v.readSecret(ctx, path, "")
	// If error is not of type secret not found, we should error
	if err != nil && errors.Is(err, esv1beta1.NoSecretError{}) {
		return nil
	}
	if err != nil {
		return err
	}
	metadata, err := v.readSecretMetadata(ctx, remoteRef.GetRemoteKey())
	if err != nil {
		return err
	}
	manager, ok := metadata["managed-by"]
	if !ok || manager != "external-secrets" {
		return nil
	}
	_, err = v.logical.DeleteWithContext(ctx, path)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultDeleteSecret, err)
	if err != nil {
		return fmt.Errorf("could not delete secret %v: %w", remoteRef.GetRemoteKey(), err)
	}
	_, err = v.logical.DeleteWithContext(ctx, metaPath)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultDeleteSecret, err)
	if err != nil {
		return fmt.Errorf("could not delete secret metadata %v: %w", remoteRef.GetRemoteKey(), err)
	}
	return nil
}

func (v *client) PushSecret(ctx context.Context, value []byte, remoteRef esv1beta1.PushRemoteRef) error {
	label := map[string]interface{}{
		"custom_metadata": map[string]string{
			"managed-by": "external-secrets",
		},
	}
	secretVal := make(map[string]interface{})
	err := json.Unmarshal(value, &secretVal)
	if err != nil {
		return fmt.Errorf("failed to convert value to a valid JSON: %w", err)
	}
	secretToPush := map[string]interface{}{
		"data": secretVal,
	}
	path := v.buildPath(remoteRef.GetRemoteKey())
	metaPath, err := v.buildMetadataPath(remoteRef.GetRemoteKey())
	if err != nil {
		return err
	}

	// Retrieve the secret map from vault and convert the secret value in string form.
	vaultSecret, err := v.readSecret(ctx, path, "")
	// If error is not of type secret not found, we should error
	if err != nil && !errors.Is(err, esv1beta1.NoSecretError{}) {
		return err
	}
	// If the secret exists (err == nil), we should check if it is managed by external-secrets
	if err == nil {
		metadata, err := v.readSecretMetadata(ctx, remoteRef.GetRemoteKey())
		if err != nil {
			return err
		}
		manager, ok := metadata["managed-by"]
		if !ok || manager != "external-secrets" {
			return fmt.Errorf("secret not managed by external-secrets")
		}
	}
	vaultSecretValue, err := json.Marshal(vaultSecret)
	if err != nil {
		return fmt.Errorf("error marshaling vault secret: %w", err)
	}
	if bytes.Equal(vaultSecretValue, value) {
		return nil
	}
	_, err = v.logical.WriteWithContext(ctx, metaPath, label)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultWriteSecretData, err)
	if err != nil {
		return err
	}
	// Otherwise, create or update the version.
	_, err = v.logical.WriteWithContext(ctx, path, secretToPush)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultWriteSecretData, err)
	return err
}

// GetAllSecrets gets multiple secrets from the provider and loads into a kubernetes secret.
// First load all secrets from secretStore path configuration
// Then, gets secrets from a matching name or matching custom_metadata.
func (v *client) GetAllSecrets(ctx context.Context, ref esv1beta1.ExternalSecretFind) (map[string][]byte, error) {
	if v.store.Version == esv1beta1.VaultKVStoreV1 {
		return nil, errors.New(errUnsupportedKvVersion)
	}
	searchPath := ""
	if ref.Path != nil {
		searchPath = *ref.Path + "/"
	}
	potentialSecrets, err := v.listSecrets(ctx, searchPath)
	if err != nil {
		return nil, err
	}
	if ref.Name != nil {
		return v.findSecretsFromName(ctx, potentialSecrets, *ref.Name)
	}
	return v.findSecretsFromTags(ctx, potentialSecrets, ref.Tags)
}

func (v *client) findSecretsFromTags(ctx context.Context, candidates []string, tags map[string]string) (map[string][]byte, error) {
	secrets := make(map[string][]byte)
	for _, name := range candidates {
		match := true
		metadata, err := v.readSecretMetadata(ctx, name)
		if err != nil {
			return nil, err
		}
		for tk, tv := range tags {
			p, ok := metadata[tk]
			if !ok || p != tv {
				match = false
				break
			}
		}
		if match {
			secret, err := v.GetSecret(ctx, esv1beta1.ExternalSecretDataRemoteRef{Key: name})
			if err != nil {
				return nil, err
			}
			if secret != nil {
				secrets[name] = secret
			}
		}
	}
	return secrets, nil
}

func (v *client) findSecretsFromName(ctx context.Context, candidates []string, ref esv1beta1.FindName) (map[string][]byte, error) {
	secrets := make(map[string][]byte)
	matcher, err := find.New(ref)
	if err != nil {
		return nil, err
	}
	for _, name := range candidates {
		ok := matcher.MatchName(name)
		if ok {
			secret, err := v.GetSecret(ctx, esv1beta1.ExternalSecretDataRemoteRef{Key: name})
			if err != nil {
				return nil, err
			}
			if secret != nil {
				secrets[name] = secret
			}
		}
	}
	return secrets, nil
}

func (v *client) listSecrets(ctx context.Context, path string) ([]string, error) {
	secrets := make([]string, 0)
	url, err := v.buildMetadataPath(path)
	if err != nil {
		return nil, err
	}
	secret, err := v.logical.ListWithContext(ctx, url)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultListSecrets, err)
	if err != nil {
		return nil, fmt.Errorf(errReadSecret, err)
	}
	if secret == nil {
		return nil, fmt.Errorf("provided path %v does not contain any secrets", url)
	}
	t, ok := secret.Data["keys"]
	if !ok {
		return nil, nil
	}
	paths := t.([]interface{})
	for _, p := range paths {
		strPath := p.(string)
		fullPath := path + strPath // because path always ends with a /
		if path == "" {
			fullPath = strPath
		}
		// Recurrently find secrets
		if !strings.HasSuffix(p.(string), "/") {
			secrets = append(secrets, fullPath)
		} else {
			partial, err := v.listSecrets(ctx, fullPath)
			if err != nil {
				return nil, err
			}
			secrets = append(secrets, partial...)
		}
	}
	return secrets, nil
}

func (v *client) readSecretMetadata(ctx context.Context, path string) (map[string]string, error) {
	metadata := make(map[string]string)
	url, err := v.buildMetadataPath(path)
	if err != nil {
		return nil, err
	}
	secret, err := v.logical.ReadWithDataWithContext(ctx, url, nil)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultReadSecretData, err)
	if err != nil {
		return nil, fmt.Errorf(errReadSecret, err)
	}
	if secret == nil {
		return nil, errors.New(errNotFound)
	}
	t, ok := secret.Data["custom_metadata"]
	if !ok {
		return nil, nil
	}
	d, ok := t.(map[string]interface{})
	if !ok {
		return metadata, nil
	}
	for k, v := range d {
		metadata[k] = v.(string)
	}
	return metadata, nil
}

// GetSecret supports two types:
//  1. get the full secret as json-encoded value
//     by leaving the ref.Property empty.
//  2. get a key from the secret.
//     Nested values are supported by specifying a gjson expression
func (v *client) GetSecret(ctx context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) ([]byte, error) {
	data, err := v.readSecret(ctx, ref.Key, ref.Version)
	if err != nil {
		return nil, err
	}
	// Return nil if secret value is null
	if data == nil {
		return nil, nil
	}
	jsonStr, err := json.Marshal(data)
	if err != nil {
		return nil, err
	}
	// (1): return raw json if no property is defined
	if ref.Property == "" {
		return jsonStr, nil
	}

	// For backwards compatibility we want the
	// actual keys to take precedence over gjson syntax
	// (2): extract key from secret with property
	if _, ok := data[ref.Property]; ok {
		return getTypedKey(data, ref.Property)
	}

	// (3): extract key from secret using gjson
	val := gjson.Get(string(jsonStr), ref.Property)
	if !val.Exists() {
		return nil, fmt.Errorf(errSecretKeyFmt, ref.Property)
	}
	return []byte(val.String()), nil
}

// GetSecretMap supports two modes of operation:
// 1. get the full secret from the vault data payload (by leaving .property empty).
// 2. extract key/value pairs from a (nested) object.
func (v *client) GetSecretMap(ctx context.Context, ref esv1beta1.ExternalSecretDataRemoteRef) (map[string][]byte, error) {
	data, err := v.GetSecret(ctx, ref)
	if err != nil {
		return nil, err
	}

	var secretData map[string]interface{}
	err = json.Unmarshal(data, &secretData)
	if err != nil {
		return nil, err
	}
	byteMap := make(map[string][]byte, len(secretData))
	for k := range secretData {
		byteMap[k], err = getTypedKey(secretData, k)
		if err != nil {
			return nil, err
		}
	}

	return byteMap, nil
}

func getTypedKey(data map[string]interface{}, key string) ([]byte, error) {
	v, ok := data[key]
	if !ok {
		return nil, fmt.Errorf(errUnexpectedKey, key)
	}
	switch t := v.(type) {
	case string:
		return []byte(t), nil
	case map[string]interface{}:
		return json.Marshal(t)
	case []byte:
		return t, nil
	// also covers int and float32 due to json.Marshal
	case float64:
		return []byte(strconv.FormatFloat(t, 'f', -1, 64)), nil
	case bool:
		return []byte(strconv.FormatBool(t)), nil
	case nil:
		return []byte(nil), nil
	default:
		return nil, errors.New(errSecretFormat)
	}
}

func (v *client) Close(ctx context.Context) error {
	// Revoke the token if we have one set, it wasn't sourced from a TokenSecretRef,
	// and token caching isn't enabled
	if !enableCache && v.client.Token() != "" && v.store.Auth.TokenSecretRef == nil {
		err := revokeTokenIfValid(ctx, v.client)
		if err != nil {
			return err
		}
	}
	return nil
}

func isReferentSpec(prov *esv1beta1.VaultProvider) bool {
	if prov.Auth.TokenSecretRef != nil && prov.Auth.TokenSecretRef.Namespace == nil {
		return true
	}
	if prov.Auth.AppRole != nil && prov.Auth.AppRole.SecretRef.Namespace == nil {
		return true
	}
	if prov.Auth.Kubernetes != nil && prov.Auth.Kubernetes.SecretRef != nil && prov.Auth.Kubernetes.SecretRef.Namespace == nil {
		return true
	}
	if prov.Auth.Kubernetes != nil && prov.Auth.Kubernetes.ServiceAccountRef != nil && prov.Auth.Kubernetes.ServiceAccountRef.Namespace == nil {
		return true
	}
	if prov.Auth.Ldap != nil && prov.Auth.Ldap.SecretRef.Namespace == nil {
		return true
	}
	if prov.Auth.Jwt != nil && prov.Auth.Jwt.SecretRef != nil && prov.Auth.Jwt.SecretRef.Namespace == nil {
		return true
	}
	if prov.Auth.Jwt != nil && prov.Auth.Jwt.KubernetesServiceAccountToken != nil && prov.Auth.Jwt.KubernetesServiceAccountToken.ServiceAccountRef.Namespace == nil {
		return true
	}
	if prov.Auth.Cert != nil && prov.Auth.Cert.SecretRef.Namespace == nil {
		return true
	}
	return false
}

func (v *client) Validate() (esv1beta1.ValidationResult, error) {
	// when using referent namespace we can not validate the token
	// because the namespace is not known yet when Validate() is called
	// from the SecretStore controller.
	if v.storeKind == esv1beta1.ClusterSecretStoreKind && isReferentSpec(v.store) {
		return esv1beta1.ValidationResultUnknown, nil
	}
	_, err := checkToken(context.Background(), v.token)
	if err != nil {
		return esv1beta1.ValidationResultError, fmt.Errorf(errInvalidCredentials, err)
	}
	return esv1beta1.ValidationResultReady, nil
}

func (v *client) buildMetadataPath(path string) (string, error) {
	var url string
	if v.store.Path == nil && !strings.Contains(path, "data") {
		return "", fmt.Errorf(errPathInvalid)
	}
	if v.store.Path == nil {
		path = strings.Replace(path, "data", "metadata", 1)
		url = path
	} else {
		url = fmt.Sprintf("%s/metadata/%s", *v.store.Path, path)
	}
	return url, nil
}

/*
	 buildPath is a helper method to build the vault equivalent path
		 from ExternalSecrets and SecretStore manifests. the path build logic
		 varies depending on the SecretStore KV version:
		 Example inputs/outputs:
		 # simple build:
		 kv version == "v2":
			provider_path: "secret/path"
			input: "foo"
			output: "secret/path/data/foo" # provider_path and data are prepended
		 kv version == "v1":
			provider_path: "secret/path"
			input: "foo"
			output: "secret/path/foo" # provider_path is prepended
		 # inheriting paths:
		 kv version == "v2":
			provider_path: "secret/path"
			input: "secret/path/foo"
			output: "secret/path/data/foo" #data is prepended
		 kv version == "v2":
			provider_path: "secret/path"
			input: "secret/path/data/foo"
			output: "secret/path/data/foo" #noop
		 kv version == "v1":
			provider_path: "secret/path"
			input: "secret/path/foo"
			output: "secret/path/foo" #noop
		 # provider path not defined:
		 kv version == "v2":
			provider_path: nil
			input: "secret/path/foo"
			output: "secret/data/path/foo" # data is prepended to secret/
		 kv version == "v2":
			provider_path: nil
			input: "secret/path/data/foo"
			output: "secret/path/data/foo" #noop
		 kv version == "v1":
			provider_path: nil
			input: "secret/path/foo"
			output: "secret/path/foo" #noop
*/
func (v *client) buildPath(path string) string {
	optionalMount := v.store.Path
	out := path
	// if optionalMount is Set, remove it from path if its there
	if optionalMount != nil {
		cut := *optionalMount + "/"
		if strings.HasPrefix(out, cut) {
			// This current logic induces a bug when the actual secret resides on same path names as the mount path.
			_, out, _ = strings.Cut(out, cut)
			// if data succeeds optionalMount on v2 store, we should remove it as well
			if strings.HasPrefix(out, "data/") && v.store.Version == esv1beta1.VaultKVStoreV2 {
				_, out, _ = strings.Cut(out, "data/")
			}
		}
		buildPath := strings.Split(out, "/")
		buildMount := strings.Split(*optionalMount, "/")
		if v.store.Version == esv1beta1.VaultKVStoreV2 {
			buildMount = append(buildMount, "data")
		}
		buildMount = append(buildMount, buildPath...)
		out = strings.Join(buildMount, "/")
		return out
	}
	if !strings.Contains(out, "/data/") && v.store.Version == esv1beta1.VaultKVStoreV2 {
		buildPath := strings.Split(out, "/")
		buildMount := []string{buildPath[0], "data"}
		buildMount = append(buildMount, buildPath[1:]...)
		out = strings.Join(buildMount, "/")
		return out
	}
	return out
}

func (v *client) readSecret(ctx context.Context, path, version string) (map[string]interface{}, error) {
	dataPath := v.buildPath(path)

	// path formated according to vault docs for v1 and v2 API
	// v1: https://www.vaultproject.io/api-docs/secret/kv/kv-v1#read-secret
	// v2: https://www.vaultproject.io/api/secret/kv/kv-v2#read-secret-version
	var params map[string][]string
	if version != "" {
		params = make(map[string][]string)
		params["version"] = []string{version}
	}
	vaultSecret, err := v.logical.ReadWithDataWithContext(ctx, dataPath, params)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultReadSecretData, err)
	if err != nil {
		return nil, fmt.Errorf(errReadSecret, err)
	}
	if vaultSecret == nil {
		return nil, esv1beta1.NoSecretError{}
	}
	secretData := vaultSecret.Data
	if v.store.Version == esv1beta1.VaultKVStoreV2 {
		// Vault KV2 has data embedded within sub-field
		// reference - https://www.vaultproject.io/api/secret/kv/kv-v2#read-secret-version
		dataInt, ok := vaultSecret.Data["data"]
		if !ok {
			return nil, errors.New(errDataField)
		}
		if dataInt == nil {
			return nil, nil
		}
		secretData, ok = dataInt.(map[string]interface{})
		if !ok {
			return nil, errors.New(errJSONUnmarshall)
		}
	}

	return secretData, nil
}

func (v *client) newConfig() (*vault.Config, error) {
	cfg := vault.DefaultConfig()
	cfg.Address = v.store.Server
	// In a controller-runtime context, we rely on the reconciliation process for retrying
	cfg.MaxRetries = 0

	if len(v.store.CABundle) == 0 && v.store.CAProvider == nil {
		return cfg, nil
	}

	caCertPool := x509.NewCertPool()

	if len(v.store.CABundle) > 0 {
		ok := caCertPool.AppendCertsFromPEM(v.store.CABundle)
		if !ok {
			return nil, errors.New(errVaultCert)
		}
	}

	if v.store.CAProvider != nil && v.storeKind == esv1beta1.ClusterSecretStoreKind && v.store.CAProvider.Namespace == nil {
		return nil, errors.New(errCANamespace)
	}

	if v.store.CAProvider != nil {
		var cert []byte
		var err error

		switch v.store.CAProvider.Type {
		case esv1beta1.CAProviderTypeSecret:
			cert, err = getCertFromSecret(v)
		case esv1beta1.CAProviderTypeConfigMap:
			cert, err = getCertFromConfigMap(v)
		default:
			return nil, errors.New(errUnknownCAProvider)
		}

		if err != nil {
			return nil, err
		}

		ok := caCertPool.AppendCertsFromPEM(cert)
		if !ok {
			return nil, errors.New(errVaultCert)
		}
	}

	if transport, ok := cfg.HttpClient.Transport.(*http.Transport); ok {
		transport.TLSClientConfig.RootCAs = caCertPool
	}

	// If either read-after-write consistency feature is enabled, enable ReadYourWrites
	cfg.ReadYourWrites = v.store.ReadYourWrites || v.store.ForwardInconsistent

	return cfg, nil
}

func getCertFromSecret(v *client) ([]byte, error) {
	secretRef := esmeta.SecretKeySelector{
		Name: v.store.CAProvider.Name,
		Key:  v.store.CAProvider.Key,
	}

	if v.store.CAProvider.Namespace != nil {
		secretRef.Namespace = v.store.CAProvider.Namespace
	}

	ctx := context.Background()
	res, err := v.secretKeyRef(ctx, &secretRef)
	if err != nil {
		return nil, fmt.Errorf(errVaultCert, err)
	}

	return []byte(res), nil
}

func getCertFromConfigMap(v *client) ([]byte, error) {
	objKey := types.NamespacedName{
		Name: v.store.CAProvider.Name,
	}

	if v.store.CAProvider.Namespace != nil {
		objKey.Namespace = *v.store.CAProvider.Namespace
	}

	configMapRef := &corev1.ConfigMap{}
	ctx := context.Background()
	err := v.kube.Get(ctx, objKey, configMapRef)
	if err != nil {
		return nil, fmt.Errorf(errVaultCert, err)
	}

	val, ok := configMapRef.Data[v.store.CAProvider.Key]
	if !ok {
		return nil, fmt.Errorf(errConfigMapFmt, v.store.CAProvider.Key)
	}

	return []byte(val), nil
}

/*
setAuth gets a new token using the configured mechanism.
If there's already a valid token, does nothing.
*/
func (v *client) setAuth(ctx context.Context, cfg *vault.Config) error {
	tokenExists := false
	var err error
	if v.client.Token() != "" {
		tokenExists, err = checkToken(ctx, v.token)
	}
	if tokenExists {
		v.log.V(1).Info("Re-using existing token")
		return err
	}

	tokenExists, err = setSecretKeyToken(ctx, v)
	if tokenExists {
		v.log.V(1).Info("Set token from secret")
		return err
	}

	tokenExists, err = setAppRoleToken(ctx, v)
	if tokenExists {
		v.log.V(1).Info("Retrieved new token using AppRole auth")
		return err
	}

	tokenExists, err = setKubernetesAuthToken(ctx, v)
	if tokenExists {
		v.log.V(1).Info("Retrieved new token using Kubernetes auth")
		return err
	}

	tokenExists, err = setLdapAuthToken(ctx, v)
	if tokenExists {
		v.log.V(1).Info("Retrieved new token using LDAP auth")
		return err
	}

	tokenExists, err = setJwtAuthToken(ctx, v)
	if tokenExists {
		v.log.V(1).Info("Retrieved new token using JWT auth")
		return err
	}

	tokenExists, err = setCertAuthToken(ctx, v, cfg)
	if tokenExists {
		v.log.V(1).Info("Retrieved new token using certificate auth")
		return err
	}

	return errors.New(errAuthFormat)
}

func setSecretKeyToken(ctx context.Context, v *client) (bool, error) {
	tokenRef := v.store.Auth.TokenSecretRef
	if tokenRef != nil {
		token, err := v.secretKeyRef(ctx, tokenRef)
		if err != nil {
			return true, err
		}
		v.client.SetToken(token)
		return true, nil
	}
	return false, nil
}

func setAppRoleToken(ctx context.Context, v *client) (bool, error) {
	appRole := v.store.Auth.AppRole
	if appRole != nil {
		err := v.requestTokenWithAppRoleRef(ctx, appRole)
		if err != nil {
			return true, err
		}
		return true, nil
	}
	return false, nil
}

func setKubernetesAuthToken(ctx context.Context, v *client) (bool, error) {
	kubernetesAuth := v.store.Auth.Kubernetes
	if kubernetesAuth != nil {
		err := v.requestTokenWithKubernetesAuth(ctx, kubernetesAuth)
		if err != nil {
			return true, err
		}
		return true, nil
	}
	return false, nil
}

func setLdapAuthToken(ctx context.Context, v *client) (bool, error) {
	ldapAuth := v.store.Auth.Ldap
	if ldapAuth != nil {
		err := v.requestTokenWithLdapAuth(ctx, ldapAuth)
		if err != nil {
			return true, err
		}
		return true, nil
	}
	return false, nil
}

func setJwtAuthToken(ctx context.Context, v *client) (bool, error) {
	jwtAuth := v.store.Auth.Jwt
	if jwtAuth != nil {
		err := v.requestTokenWithJwtAuth(ctx, jwtAuth)
		if err != nil {
			return true, err
		}
		return true, nil
	}
	return false, nil
}

func setCertAuthToken(ctx context.Context, v *client, cfg *vault.Config) (bool, error) {
	certAuth := v.store.Auth.Cert
	if certAuth != nil {
		err := v.requestTokenWithCertAuth(ctx, certAuth, cfg)
		if err != nil {
			return true, err
		}
		return true, nil
	}
	return false, nil
}

func (v *client) secretKeyRefForServiceAccount(ctx context.Context, serviceAccountRef *esmeta.ServiceAccountSelector) (string, error) {
	serviceAccount := &corev1.ServiceAccount{}
	ref := types.NamespacedName{
		Namespace: v.namespace,
		Name:      serviceAccountRef.Name,
	}
	if (v.storeKind == esv1beta1.ClusterSecretStoreKind) &&
		(serviceAccountRef.Namespace != nil) {
		ref.Namespace = *serviceAccountRef.Namespace
	}
	err := v.kube.Get(ctx, ref, serviceAccount)
	if err != nil {
		return "", fmt.Errorf(errGetKubeSA, ref.Name, err)
	}
	if len(serviceAccount.Secrets) == 0 {
		return "", fmt.Errorf(errGetKubeSASecrets, ref.Name)
	}
	for _, tokenRef := range serviceAccount.Secrets {
		retval, err := v.secretKeyRef(ctx, &esmeta.SecretKeySelector{
			Name:      tokenRef.Name,
			Namespace: &ref.Namespace,
			Key:       "token",
		})

		if err != nil {
			continue
		}

		return retval, nil
	}
	return "", fmt.Errorf(errGetKubeSANoToken, ref.Name)
}

func (v *client) secretKeyRef(ctx context.Context, secretRef *esmeta.SecretKeySelector) (string, error) {
	secret := &corev1.Secret{}
	ref := types.NamespacedName{
		Namespace: v.namespace,
		Name:      secretRef.Name,
	}
	if (v.storeKind == esv1beta1.ClusterSecretStoreKind) &&
		(secretRef.Namespace != nil) {
		ref.Namespace = *secretRef.Namespace
	}
	err := v.kube.Get(ctx, ref, secret)
	if err != nil {
		return "", fmt.Errorf(errGetKubeSecret, ref.Name, err)
	}

	keyBytes, ok := secret.Data[secretRef.Key]
	if !ok {
		return "", fmt.Errorf(errSecretKeyFmt, secretRef.Key)
	}

	value := string(keyBytes)
	valueStr := strings.TrimSpace(value)
	return valueStr, nil
}

func (v *client) serviceAccountToken(ctx context.Context, serviceAccountRef esmeta.ServiceAccountSelector, additionalAud []string, expirationSeconds int64) (string, error) {
	audiences := serviceAccountRef.Audiences
	if len(additionalAud) > 0 {
		audiences = append(audiences, additionalAud...)
	}
	tokenRequest := &authenticationv1.TokenRequest{
		ObjectMeta: metav1.ObjectMeta{
			Namespace: v.namespace,
		},
		Spec: authenticationv1.TokenRequestSpec{
			Audiences:         audiences,
			ExpirationSeconds: &expirationSeconds,
		},
	}
	if (v.storeKind == esv1beta1.ClusterSecretStoreKind) &&
		(serviceAccountRef.Namespace != nil) {
		tokenRequest.Namespace = *serviceAccountRef.Namespace
	}
	tokenResponse, err := v.corev1.ServiceAccounts(tokenRequest.Namespace).CreateToken(ctx, serviceAccountRef.Name, tokenRequest, metav1.CreateOptions{})
	if err != nil {
		return "", fmt.Errorf(errGetKubeSATokenRequest, serviceAccountRef.Name, err)
	}
	return tokenResponse.Status.Token, nil
}

// checkToken does a lookup and checks if the provided token exists.
func checkToken(ctx context.Context, token Token) (bool, error) {
	// https://www.vaultproject.io/api-docs/auth/token#lookup-a-token-self
	resp, err := token.LookupSelfWithContext(ctx)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultLookupSelf, err)
	if err != nil {
		return false, err
	}
	t, ok := resp.Data["type"]
	if !ok {
		return false, fmt.Errorf("could not assert token type")
	}
	tokenType := t.(string)
	if tokenType == "batch" {
		return false, nil
	}
	return true, nil
}

func revokeTokenIfValid(ctx context.Context, client Client) error {
	valid, err := checkToken(ctx, client.AuthToken())
	if err != nil {
		return fmt.Errorf(errVaultRevokeToken, err)
	}
	if valid {
		err = client.AuthToken().RevokeSelfWithContext(ctx, client.Token())
		metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultRevokeSelf, err)
		if err != nil {
			return fmt.Errorf(errVaultRevokeToken, err)
		}
		client.ClearToken()
	}
	return nil
}

func (v *client) requestTokenWithAppRoleRef(ctx context.Context, appRole *esv1beta1.VaultAppRole) error {
	roleID := strings.TrimSpace(appRole.RoleID)

	secretID, err := v.secretKeyRef(ctx, &appRole.SecretRef)
	if err != nil {
		return err
	}
	secret := approle.SecretID{FromString: secretID}
	appRoleClient, err := approle.NewAppRoleAuth(roleID, &secret, approle.WithMountPath(appRole.Path))
	if err != nil {
		return err
	}
	_, err = v.auth.Login(ctx, appRoleClient)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultLogin, err)
	if err != nil {
		return err
	}
	return nil
}

func (v *client) requestTokenWithKubernetesAuth(ctx context.Context, kubernetesAuth *esv1beta1.VaultKubernetesAuth) error {
	jwtString, err := getJwtString(ctx, v, kubernetesAuth)
	if err != nil {
		return err
	}
	k, err := authkubernetes.NewKubernetesAuth(kubernetesAuth.Role, authkubernetes.WithServiceAccountToken(jwtString), authkubernetes.WithMountPath(kubernetesAuth.Path))
	if err != nil {
		return err
	}
	_, err = v.auth.Login(ctx, k)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultLogin, err)
	if err != nil {
		return err
	}
	return nil
}

func getJwtString(ctx context.Context, v *client, kubernetesAuth *esv1beta1.VaultKubernetesAuth) (string, error) {
	if kubernetesAuth.ServiceAccountRef != nil {
		// Kubernetes <v1.24 fetch token via ServiceAccount.Secrets[]
		// this behavior was removed in v1.24 and we must use TokenRequest API (see below)
		jwt, err := v.secretKeyRefForServiceAccount(ctx, kubernetesAuth.ServiceAccountRef)
		if jwt != "" {
			return jwt, err
		}
		if err != nil {
			v.log.V(1).Info("unable to fetch jwt from service account secret, trying service account token next")
		}
		// Kubernetes >=v1.24: fetch token via TokenRequest API
		// note: this is a massive change from vault perspective: the `iss` claim will very likely change.
		// Vault 1.9 deprecated issuer validation by default, and authentication with Vault clusters <1.9 will likely fail.
		jwt, err = v.serviceAccountToken(ctx, *kubernetesAuth.ServiceAccountRef, nil, 600)
		if err != nil {
			return "", err
		}
		return jwt, nil
	} else if kubernetesAuth.SecretRef != nil {
		tokenRef := kubernetesAuth.SecretRef
		if tokenRef.Key == "" {
			tokenRef = kubernetesAuth.SecretRef.DeepCopy()
			tokenRef.Key = "token"
		}
		jwt, err := v.secretKeyRef(ctx, tokenRef)
		if err != nil {
			return "", err
		}
		return jwt, nil
	} else {
		// Kubernetes authentication is specified, but without a referenced
		// Kubernetes secret. We check if the file path for in-cluster service account
		// exists and attempt to use the token for Vault Kubernetes auth.
		if _, err := os.Stat(serviceAccTokenPath); err != nil {
			return "", fmt.Errorf(errServiceAccount, err)
		}
		jwtByte, err := os.ReadFile(serviceAccTokenPath)
		if err != nil {
			return "", fmt.Errorf(errServiceAccount, err)
		}
		return string(jwtByte), nil
	}
}

func (v *client) requestTokenWithLdapAuth(ctx context.Context, ldapAuth *esv1beta1.VaultLdapAuth) error {
	username := strings.TrimSpace(ldapAuth.Username)

	password, err := v.secretKeyRef(ctx, &ldapAuth.SecretRef)
	if err != nil {
		return err
	}
	pass := authldap.Password{FromString: password}
	l, err := authldap.NewLDAPAuth(username, &pass, authldap.WithMountPath(ldapAuth.Path))
	if err != nil {
		return err
	}
	_, err = v.auth.Login(ctx, l)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultLogin, err)
	if err != nil {
		return err
	}
	return nil
}

func (v *client) requestTokenWithJwtAuth(ctx context.Context, jwtAuth *esv1beta1.VaultJwtAuth) error {
	role := strings.TrimSpace(jwtAuth.Role)
	var jwt string
	var err error
	if jwtAuth.SecretRef != nil {
		jwt, err = v.secretKeyRef(ctx, jwtAuth.SecretRef)
	} else if k8sServiceAccountToken := jwtAuth.KubernetesServiceAccountToken; k8sServiceAccountToken != nil {
		audiences := k8sServiceAccountToken.Audiences
		if audiences == nil {
			audiences = &[]string{"vault"}
		}
		expirationSeconds := k8sServiceAccountToken.ExpirationSeconds
		if expirationSeconds == nil {
			tmp := int64(600)
			expirationSeconds = &tmp
		}
		jwt, err = v.serviceAccountToken(ctx, k8sServiceAccountToken.ServiceAccountRef, *audiences, *expirationSeconds)
	} else {
		err = fmt.Errorf(errJwtNoTokenSource)
	}
	if err != nil {
		return err
	}

	parameters := map[string]interface{}{
		"role": role,
		"jwt":  jwt,
	}
	url := strings.Join([]string{"auth", jwtAuth.Path, "login"}, "/")
	vaultResult, err := v.logical.WriteWithContext(ctx, url, parameters)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultWriteSecretData, err)
	if err != nil {
		return err
	}

	token, err := vaultResult.TokenID()
	if err != nil {
		return fmt.Errorf(errVaultToken, err)
	}
	v.client.SetToken(token)
	return nil
}

func (v *client) requestTokenWithCertAuth(ctx context.Context, certAuth *esv1beta1.VaultCertAuth, cfg *vault.Config) error {
	clientKey, err := v.secretKeyRef(ctx, &certAuth.SecretRef)
	if err != nil {
		return err
	}

	clientCert, err := v.secretKeyRef(ctx, &certAuth.ClientCert)
	if err != nil {
		return err
	}

	cert, err := tls.X509KeyPair([]byte(clientCert), []byte(clientKey))
	if err != nil {
		return fmt.Errorf(errClientTLSAuth, err)
	}

	if transport, ok := cfg.HttpClient.Transport.(*http.Transport); ok {
		transport.TLSClientConfig.Certificates = []tls.Certificate{cert}
	}

	url := strings.Join([]string{"auth", "cert", "login"}, "/")
	vaultResult, err := v.logical.WriteWithContext(ctx, url, nil)
	metrics.ObserveAPICall(metrics.ProviderHCVault, metrics.CallHCVaultWriteSecretData, err)
	if err != nil {
		return fmt.Errorf(errVaultRequest, err)
	}
	token, err := vaultResult.TokenID()
	if err != nil {
		return fmt.Errorf(errVaultToken, err)
	}
	v.client.SetToken(token)
	return nil
}

func init() {
	var vaultTokenCacheSize int
	fs := pflag.NewFlagSet("vault", pflag.ExitOnError)
	fs.BoolVar(&enableCache, "experimental-enable-vault-token-cache", false, "Enable experimental Vault token cache. External secrets will reuse the Vault token without creating a new one on each request.")
	// max. 265k vault leases with 30bytes each ~= 7MB
	fs.IntVar(&vaultTokenCacheSize, "experimental-vault-token-cache-size", 2<<17, "Maximum size of Vault token cache. When more tokens than Only used if --experimental-enable-vault-token-cache is set.")
	lateInit := func() {
		logger.Info("initializing vault cache with size=%d", vaultTokenCacheSize)
		clientCache = cache.Must(vaultTokenCacheSize, func(client Client) {
			err := revokeTokenIfValid(context.Background(), client)
			if err != nil {
				logger.Error(err, "unable to revoke cached token on eviction")
			}
		})
	}
	feature.Register(feature.Feature{
		Flags:      fs,
		Initialize: lateInit,
	})

	esv1beta1.Register(&connector{
		newVaultClient: newVaultClient,
	}, &esv1beta1.SecretStoreProvider{
		Vault: &esv1beta1.VaultProvider{},
	})
}