feat: Add Kubernetes Secret backend

Signed-off-by: Dennis Lapchenko <[email protected]>

docs/backends.md

@@ -705,3 +705,73 @@ type: Opaque
 data:
   password: <path:secret-id#key | base64encode>
 ```
+
+### Kubernetes Secret
+
+Inject values from any kubernetes secret
+
+**Note**: The Kubernetes Secret backend does not support versioning
+
+##### Kubernetes Secret Authentication
+
+Backend inherits same in-cluster service-account as the plugin itself
+
+These are the parameters for Kubernetes Secret:
+
+```
+AVP_TYPE: kubernetessecret
+```
+
+##### Examples
+
+###### Path Annotation
+
+```yaml
+kind: Secret
+apiVersion: v1
+metadata:
+  name: test-secret
+  annotations:
+    avp.kubernetes.io/path: "my-secret"
+type: Opaque
+data:
+  password: <key>
+```
+
+###### Path Annotation With Namespace
+
+```yaml
+kind: Secret
+apiVersion: v1
+metadata:
+  name: test-secret
+  annotations:
+    avp.kubernetes.io/path: "prod:my-secret"
+type: Opaque
+data:
+  password: <key>
+```
+
+###### Inline Path
+
+```yaml
+kind: Secret
+apiVersion: v1
+metadata:
+  name: test-secret
+type: Opaque
+data:
+  password: <path:my-secret#key>
+```
+
+###### Inline Path With Namespace
+
+```yaml
+kind: Secret
+apiVersion: v1
+metadata:
+  name: test-secret
+type: Opaque
+data:
+  password: <path:prod:my-secret#key>
+```

go.mod

@@ -212,7 +212,7 @@ require (
 	github.com/pelletier/go-toml/v2 v2.0.1 // indirect
 	github.com/petermattis/goid v0.0.0-20180202154549-b0b1615b78e5 // indirect
 	github.com/pires/go-proxyproto v0.6.1 // indirect
-	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pkg/errors v0.9.1
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/posener/complete v1.2.3 // indirect
 	github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect

pkg/backends/kubernetessecret.go

@@ -0,0 +1,60 @@
+package backends
+
+import (
+	"github.com/argoproj-labs/argocd-vault-plugin/pkg/kube"
+	"github.com/argoproj-labs/argocd-vault-plugin/pkg/utils"
+	"github.com/pkg/errors"
+)
+
+type kubeSecretsClient interface {
+	ReadSecretData(string) (map[string][]byte, error)
+}
+
+// KubernetesSecret is a struct for working with a Kubernetes Secret backend
+type KubernetesSecret struct {
+	client kubeSecretsClient
+}
+
+// NewKubernetesSecret returns a new Kubernetes Secret backend.
+func NewKubernetesSecret() *KubernetesSecret {
+	return &KubernetesSecret{}
+}
+
+// Login initiates kubernetes client
+func (k *KubernetesSecret) Login() error {
+	localClient, err := kube.NewClient()
+	if err != nil {
+		return errors.Wrap(err, "Failed to perform login for kubernetes secret backend")
+	}
+	k.client = localClient
+	return nil
+}
+
+// GetSecrets gets secrets from Kubernetes Secret and returns the formatted data
+func (k *KubernetesSecret) GetSecrets(path string, version string, annotations map[string]string) (map[string]interface{}, error) {
+	utils.VerboseToStdErr("K8s Secret getting secret: %s", path)
+	data, err := k.client.ReadSecretData(path)
+	if err != nil {
+		return nil, err
+	}
+
+	out := make(map[string]interface{}, len(data))
+	for k, v := range data {
+		out[k] = string(v)
+	}
+
+	utils.VerboseToStdErr("K8s Secret get secret response: %v", out)
+	return out, nil
+}
+
+// GetIndividualSecret will get the specific secret (placeholder) from the Kubernetes Secret backend
+// Kubernetes Secrets can only be wholly read,
+// So, we use GetSecrets and extract the specific placeholder we want
+func (k *KubernetesSecret) GetIndividualSecret(path, secret, version string, annotations map[string]string) (interface{}, error) {
+	utils.VerboseToStdErr("K8s Secret getting secret %s and key %s", path, secret)
+	data, err := k.GetSecrets(path, version, annotations)
+	if err != nil {
+		return nil, err
+	}
+	return data[secret], nil
+}

pkg/backends/kubernetessecret_test.go

@@ -0,0 +1,110 @@
+package backends
+
+import (
+	"reflect"
+	"testing"
+)
+
+func newMockK8sClient(vals map[string]map[string]string, err error) *mockK8sClient {
+	encoded := make(map[string]map[string][]byte)
+	for path, secrets := range vals {
+		encoded[path] = make(map[string][]byte)
+		for key, value := range secrets {
+			encoded[path][key] = []byte(value)
+		}
+	}
+	return &mockK8sClient{
+		responses_by_path: encoded,
+		err:               err,
+	}
+}
+
+type mockK8sClient struct {
+	responses_by_path map[string]map[string][]byte
+	err               error
+}
+
+func (m *mockK8sClient) ReadSecretData(path string) (map[string][]byte, error) {
+	return m.responses_by_path[path], m.err
+}
+
+func TestKubernetesSecretGetSecrets(t *testing.T) {
+	sm := NewKubernetesSecret()
+	sm.client = newMockK8sClient(map[string]map[string]string{
+		"secret1": {
+			"test-secret": "current-value",
+			"test2":       "bar",
+		},
+		"secret2": {
+			"key": "foz",
+		},
+	}, nil)
+
+	t.Run("Get secrets from first path", func(t *testing.T) {
+		data, err := sm.GetSecrets("secret1", "", map[string]string{})
+		if err != nil {
+			t.Fatalf("expected 0 errors but got: %s", err)
+		}
+
+		expected := map[string]interface{}{
+			"test-secret": "current-value",
+			"test2":       "bar",
+		}
+
+		if !reflect.DeepEqual(expected, data) {
+			t.Errorf("expected: %s, got: %s.", expected, data)
+		}
+	})
+
+	t.Run("GetIndividualSecret from first path", func(t *testing.T) {
+		secret, err := sm.GetIndividualSecret("secret1", "test2", "", map[string]string{})
+		if err != nil {
+			t.Fatalf("expected 0 errors but got: %s", err)
+		}
+
+		expected := "bar"
+
+		if !reflect.DeepEqual(expected, secret) {
+			t.Errorf("expected: %s, got: %s.", expected, secret)
+		}
+	})
+
+	t.Run("Get secrets from secret from second path", func(t *testing.T) {
+		data, err := sm.GetSecrets("secret2", "", map[string]string{})
+		if err != nil {
+			t.Fatalf("expected 0 errors but got: %s", err)
+		}
+
+		expected := map[string]interface{}{
+			"key": "foz",
+		}
+
+		if !reflect.DeepEqual(expected, data) {
+			t.Errorf("expected: %s, got: %s.", expected, data)
+		}
+	})
+
+	t.Run("GetIndividualSecret from inline path secret", func(t *testing.T) {
+		secret, err := sm.GetIndividualSecret("secret2", "key", "", map[string]string{})
+		if err != nil {
+			t.Fatalf("expected 0 errors but got: %s", err)
+		}
+
+		expected := "foz"
+
+		if !reflect.DeepEqual(expected, secret) {
+			t.Errorf("expected: %s, got: %s.", expected, secret)
+		}
+	})
+
+	t.Run("GetIndividualSecretNotFound", func(t *testing.T) {
+		secret, err := sm.GetIndividualSecret("test", "22test2", "", map[string]string{})
+		if err != nil {
+			t.Fatalf("expected 0 errors but got: %s", err)
+		}
+
+		if secret != nil {
+			t.Errorf("expected: %s, got: %s.", "nil", secret)
+		}
+	})
+}

pkg/config/config.go

@@ -49,6 +49,7 @@ var backendPrefixes []string = []string{
 	"google",
 	"sops",
 	"op_connect",
+	"k8s_secret",
 }
 
 // New returns a new Config struct
@@ -278,6 +279,10 @@ func New(v *viper.Viper, co *Options) (*Config, error) {
 			}
 			backend = backends.NewDelineaSecretServerBackend(tss)
 		}
+	case types.KubernetesSecretBackend:
+		{
+			backend = backends.NewKubernetesSecret()
+		}
 	default:
 		return nil, fmt.Errorf("Must provide a supported Vault Type, received %s", v.GetString(types.EnvAvpType))
 	}

pkg/config/config_test.go

@@ -219,6 +219,12 @@ fDGt+yaf3RaZbVwHSVLzxiXGsu1WQJde3uJeNh5c6z+5
 			},
 			"*backends.DelineaSecretServer",
 		},
+		{
+			map[string]interface{}{
+				"AVP_TYPE": "kubernetessecret",
+			},
+			"*backends.KubernetesSecret",
+		},
 	}
 	for _, tc := range testCases {
 		for k, v := range tc.environment {

pkg/kube/client.go

@@ -32,9 +32,9 @@ func NewClient() (*Client, error) {
 	}, nil
 }
 
-// ReadSecret reads the specified Secret from the defined namespace, otherwise defaults to `argocd`
-// and returns a YAML []byte containing its data, decoded from base64
-func (c *Client) ReadSecret(name string) ([]byte, error) {
+// ReadSecretData reads the specified Secret from the defined namespace, otherwise defaults to `argocd`
+// and returns map[string][]byte containing its data
+func (c *Client) ReadSecretData(name string) (map[string][]byte, error) {
 	secretNamespace, secretName := secretNamespaceName(name)
 
 	utils.VerboseToStdErr("parsed secret name as %s from namespace %s", secretName, secretNamespace)
@@ -43,8 +43,20 @@ func (c *Client) ReadSecret(name string) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	return s.Data, nil
+}
+
+// ReadSecret reads the specified Secret from the defined namespace, otherwise defaults to `argocd`
+// and returns a YAML []byte containing its data, decoded from base64
+func (c *Client) ReadSecret(name string) ([]byte, error) {
+	data, err := c.ReadSecretData(name)
+	if err != nil {
+		return nil, err
+	}
+
 	decoded := make(map[string]string)
-	for key, value := range s.Data {
+	for key, value := range data {
 		decoded[key] = string(value)
 	}
 	res, err := k8yaml.Marshal(&decoded)

pkg/types/constants.go

@@ -43,6 +43,7 @@ const (
 	DelineaSecretServerbackend  = "delineasecretserver"
 	OnePasswordConnect          = "1passwordconnect"
 	KeeperSecretsManagerBackend = "keepersecretsmanager"
+	KubernetesSecretBackend     = "kubernetessecret"
 	K8sAuth                     = "k8s"
 	ApproleAuth                 = "approle"
 	GithubAuth                  = "github"