feat: Allow TriggerAuthentication defaults via ENV variables for HashiCorp Vault

CHANGELOG.md

@@ -63,6 +63,7 @@ Here is an overview of all new **experimental** features:
 - **General**: Add parameter queryParameters to prometheus-scaler ([#4962](https://github.com/kedacore/keda/issues/4962))
 - **General**: Support TriggerAuthentication properties from ConfigMap ([#4830](https://github.com/kedacore/keda/issues/4830))
 - **Hashicorp Vault**: Add support to get secret that needs write operation (e.g. pki) ([#5067](https://github.com/kedacore/keda/issues/5067))
+- **Hashicorp Vault**: Allow setting vault TriggerAuthentication defaults via ENV variables ([#4965](https://github.com/kedacore/keda/issues/4965))
 - **Hashicorp Vault**: Fix operator panic when spec.hashiCorpVault.credential.serviceAccount is not set ([#4964](https://github.com/kedacore/keda/issues/4964))
 - **Kafka Scaler**: Ability to set upper bound to the number of partitions with lag ([#3997](https://github.com/kedacore/keda/issues/3997))
 - **Kafka Scaler**: Add more logging to check Sarama DescribeTopics method ([#5102](https://github.com/kedacore/keda/issues/5102))

apis/keda/v1alpha1/triggerauthentication_types.go

@@ -170,9 +170,13 @@ type AuthEnvironment struct {
 
 // HashiCorpVault is used to authenticate using Hashicorp Vault
 type HashiCorpVault struct {
-	Address        string              `json:"address"`
+	Secrets []VaultSecret `json:"secrets"`
+
+	// +optional
+	Address string `json:"address"`
+
+	// +optional
 	Authentication VaultAuthentication `json:"authentication"`
-	Secrets        []VaultSecret       `json:"secrets"`
 
 	// +optional
 	Namespace string `json:"namespace,omitempty"`

config/crd/bases/keda.sh_clustertriggerauthentications.yaml

@@ -233,8 +233,6 @@ spec:
                       type: object
                     type: array
                 required:
-                - address
-                - authentication
                 - secrets
                 type: object
               podIdentity:

config/crd/bases/keda.sh_triggerauthentications.yaml

@@ -232,8 +232,6 @@ spec:
                       type: object
                     type: array
                 required:
-                - address
-                - authentication
                 - secrets
                 type: object
               podIdentity:

pkg/scaling/resolver/hashicorpvault_handler.go

@@ -27,6 +27,7 @@ import (
 	vaultapi "github.com/hashicorp/vault/api"
 
 	kedav1alpha1 "github.com/kedacore/keda/v2/apis/keda/v1alpha1"
+	"github.com/kedacore/keda/v2/pkg/util"
 )
 
 // HashicorpVaultHandler is specification of Hashi Corp Vault
@@ -43,9 +44,46 @@ func NewHashicorpVaultHandler(v *kedav1alpha1.HashiCorpVault) *HashicorpVaultHan
 	}
 }
 
+func (vh *HashicorpVaultHandler) SetFromEnvironment() {
+	if vh.vault.Address == "" {
+		vh.vault.Address = util.ResolveOsString("VAULT_ADDR", "")
+	}
+
+	if vh.vault.Authentication == "" {
+		vh.vault.Authentication = kedav1alpha1.VaultAuthentication(util.ResolveOsString("VAULT_AUTH", ""))
+	}
+
+	if vh.vault.Role == "" {
+		vh.vault.Role = util.ResolveOsString("VAULT_ROLE", "")
+	}
+
+	if vh.vault.Mount == "" {
+		vh.vault.Mount = util.ResolveOsString("VAULT_MOUNT", "")
+	}
+
+	if vh.vault.Credential == nil {
+		serviceAccount := util.ResolveOsString("VAULT_JWT_PATH", "")
+		vaultToken := util.ResolveOsString("VAULT_TOKEN", "")
+		if vaultToken != "" {
+			vh.vault.Credential = &kedav1alpha1.Credential{}
+			vh.vault.Credential.Token = vaultToken
+		}
+		if serviceAccount != "" {
+			vh.vault.Credential = &kedav1alpha1.Credential{}
+			vh.vault.Credential.ServiceAccount = serviceAccount
+		}
+	}
+
+	if vh.vault.Namespace == "" {
+		vh.vault.Namespace = util.ResolveOsString("VAULT_NAMESPACE", "")
+	}
+}
+
 // Initialize the Vault client
 func (vh *HashicorpVaultHandler) Initialize(logger logr.Logger) error {
 	config := vaultapi.DefaultConfig()
+	vh.SetFromEnvironment()
+
 	client, err := vaultapi.NewClient(config)
 	if err != nil {
 		return err

pkg/scaling/resolver/hashicorpvault_handler_test.go

@@ -24,6 +24,7 @@ import (
 	"math"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"testing"
 
 	vaultapi "github.com/hashicorp/vault/api"
@@ -120,9 +121,13 @@ func TestGetPkiRequest(t *testing.T) {
 func mockVault(t *testing.T) *httptest.Server {
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		var data map[string]interface{}
+		var auth *vaultapi.SecretAuth
 		switch r.URL.Path {
+		case "/v1/auth/kubernetes/login":
+			auth = &vaultapi.SecretAuth{
+				ClientToken: "38fe9691-e623-7238-f618-c94d4e7bc674",
+			}
 		case "/v1/auth/token/lookup-self":
-
 			data = vaultTokenSelf
 		case "/v1/kv_v2/data/keda": //todo: more generic
 			data = kvV2SecretDataKeda
@@ -160,7 +165,7 @@ func mockVault(t *testing.T) *httptest.Server {
 			Data:          data,
 			Renewable:     false,
 			Warnings:      nil,
-			Auth:          nil,
+			Auth:          auth,
 			WrapInfo:      nil,
 		}
 		var out, _ = json.Marshal(secret)
@@ -169,6 +174,49 @@ func mockVault(t *testing.T) *httptest.Server {
 	return server
 }
 
+func TestHashicorpVaultLoadFromENVVariablesToken(t *testing.T) {
+	server := mockVault(t)
+	defer server.Close()
+
+	t.Setenv("VAULT_ADDR", server.URL)
+	t.Setenv("VAULT_MOUNT", "kubernetes")
+	t.Setenv("VAULT_AUTH", "token")
+	t.Setenv("VAULT_ROLE", "my-role")
+	t.Setenv("VAULT_NAMESPACE", "")
+	t.Setenv("VAULT_TOKEN", vaultTestToken)
+
+	vault := kedav1alpha1.HashiCorpVault{}
+	vaultHandler := NewHashicorpVaultHandler(&vault)
+
+	err := vaultHandler.Initialize(logf.Log.WithName("test"))
+	defer vaultHandler.Stop()
+	assert.Nil(t, err)
+}
+
+func TestHashicorpVaultLoadFromENVVariablesKubernetes(t *testing.T) {
+	server := mockVault(t)
+	defer server.Close()
+
+	t.Setenv("VAULT_ADDR", server.URL)
+	t.Setenv("VAULT_MOUNT", "kubernetes")
+	t.Setenv("VAULT_AUTH", "kubernetes")
+	t.Setenv("VAULT_ROLE", "my-role")
+	t.Setenv("VAULT_NAMESPACE", "")
+
+	tmpServiceToken, err := os.CreateTemp("", "token")
+	assert.Nil(t, err)
+	defer tmpServiceToken.Close()
+
+	t.Setenv("VAULT_JWT_PATH", tmpServiceToken.Name())
+
+	vault := kedav1alpha1.HashiCorpVault{}
+	vaultHandler := NewHashicorpVaultHandler(&vault)
+
+	err = vaultHandler.Initialize(logf.Log.WithName("test"))
+	defer vaultHandler.Stop()
+	assert.Nil(t, err)
+}
+
 func TestHashicorpVaultHandler_getSecretValue_specify_secret_type(t *testing.T) {
 	server := mockVault(t)
 	defer server.Close()

pkg/util/env_resolver.go

@@ -57,6 +57,16 @@ func ResolveOsEnvDuration(envName string) (*time.Duration, error) {
 	return nil, nil
 }
 
+func ResolveOsString(envName string, defaultvalue string) string {
+	valueStr, found := os.LookupEnv(envName)
+
+	if found && valueStr != "" {
+		return valueStr
+	}
+
+	return defaultvalue
+}
+
 // GetClusterObjectNamespace retrieves the cluster object namespace of KEDA, default is the namespace of KEDA Operator & Metrics Server
 func GetClusterObjectNamespace() (string, error) {
 	// Check if a cached value is available.