fix: renew token of vault k8s auth method

dependency/vault_token.go

@@ -8,6 +8,9 @@ import (
 	"github.com/pkg/errors"
 )
 
+// VaultTokenRefreshCurrent tells to refresh the current client token.
+const VaultTokenRefreshCurrent = ""
+
 // Ensure implements
 var _ Dependency = (*VaultTokenQuery)(nil)
 
@@ -16,6 +19,8 @@ type VaultTokenQuery struct {
 	stopCh      chan struct{}
 	secret      *Secret
 	vaultSecret *api.Secret
+
+	initialToken string
 }
 
 // NewVaultTokenQuery creates a new dependency.
@@ -28,9 +33,10 @@ func NewVaultTokenQuery(token string) (*VaultTokenQuery, error) {
 		},
 	}
 	return &VaultTokenQuery{
-		stopCh:      make(chan struct{}, 1),
-		vaultSecret: vaultSecret,
-		secret:      transformSecret(vaultSecret),
+		stopCh:       make(chan struct{}, 1),
+		vaultSecret:  vaultSecret,
+		secret:       transformSecret(vaultSecret),
+		initialToken: token,
 	}, nil
 }
 
@@ -43,8 +49,16 @@ func (d *VaultTokenQuery) Fetch(clients *ClientSet, opts *QueryOptions,
 	default:
 	}
 
-	if vaultSecretRenewable(d.secret) {
-		err := renewSecret(clients, d)
+	var currentRenewer renewer = d
+
+	if d.initialToken == VaultTokenRefreshCurrent {
+		currentRenewer = newVaultSecretsOverrideRenewer(d, clients.Vault().Token())
+	}
+
+	secret, _ := currentRenewer.secrets()
+
+	if vaultSecretRenewable(secret) {
+		err := renewSecret(clients, currentRenewer)
 		if err != nil {
 			return nil, nil, errors.Wrap(err, d.String())
 		}
@@ -80,3 +94,30 @@ func (d *VaultTokenQuery) String() string {
 func (d *VaultTokenQuery) Type() Type {
 	return TypeVault
 }
+
+func newVaultSecretsOverrideRenewer(parent renewer, token string) *vaultSecretsOverrideRenewer {
+	vaultSecret := &api.Secret{
+		Auth: &api.SecretAuth{
+			ClientToken:   token,
+			Renewable:     true,
+			LeaseDuration: 1,
+		},
+	}
+
+	return &vaultSecretsOverrideRenewer{
+		renewer:     parent,
+		vaultSecret: vaultSecret,
+		secret:      transformSecret(vaultSecret),
+	}
+}
+
+type vaultSecretsOverrideRenewer struct {
+	renewer
+
+	secret      *Secret
+	vaultSecret *api.Secret
+}
+
+func (d *vaultSecretsOverrideRenewer) secrets() (*Secret, *api.Secret) {
+	return d.secret, d.vaultSecret
+}

dependency/vault_token_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/hashicorp/vault/api"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestNewVaultTokenQuery(t *testing.T) {
@@ -76,3 +77,22 @@ func TestVaultTokenQuery_String(t *testing.T) {
 		})
 	}
 }
+
+func TestTewVaultSecretsOverrideRenewer(t *testing.T) {
+	const token = "expected_token"
+
+	parent, err := NewVaultTokenQuery(VaultTokenRefreshCurrent)
+	require.NoError(t, err)
+
+	vaultTokenSecretsOverride := newVaultSecretsOverrideRenewer(parent, token)
+
+	secret, vaultSecret := vaultTokenSecretsOverride.secrets()
+
+	if assert.NotNil(t, secret) && assert.NotNil(t, secret.Auth) {
+		assert.Equal(t, token, secret.Auth.ClientToken)
+	}
+
+	if assert.NotNil(t, vaultSecret) && assert.NotNil(t, vaultSecret.Auth) {
+		assert.Equal(t, token, vaultSecret.Auth.ClientToken)
+	}
+}

watch/vault_token.go

@@ -15,6 +15,36 @@ import (
 	"github.com/hashicorp/vault/api"
 )
 
+func newVaultK8SAuthMethodRefreshTokenWatcher(
+	clients *dep.ClientSet, c *config.VaultConfig, doneCh chan struct{},
+) (*Watcher, error) {
+	isK8SAuthMethod := config.StringVal(c.K8SServiceAccountToken) != "" || config.StringVal(c.K8SServiceAccountTokenPath) != ""
+
+	if !isK8SAuthMethod || !config.BoolVal(c.RenewToken) {
+		return nil, nil
+	}
+
+	watcher := NewWatcher(&NewWatcherInput{
+		Clients:        clients,
+		RetryFuncVault: RetryFunc(c.Retry.RetryFunc()),
+	})
+
+	vaultQuery, err := dep.NewVaultTokenQuery(dep.VaultTokenRefreshCurrent)
+	if err != nil {
+		watcher.Stop()
+
+		return nil, fmt.Errorf("vaultwatcher: %w", err)
+	}
+
+	if _, err := watcher.Add(vaultQuery); err != nil {
+		watcher.Stop()
+
+		return nil, fmt.Errorf("vaultwatcher: %w", err)
+	}
+
+	return watcher, nil
+}
+
 // VaultTokenWatcher monitors the vault token for updates
 func VaultTokenWatcher(
 	clients *dep.ClientSet, c *config.VaultConfig, doneCh chan struct{},
@@ -24,7 +54,7 @@ func VaultTokenWatcher(
 	// tokens are not being used.
 	raw_token := strings.TrimSpace(config.StringVal(c.Token))
 	if raw_token == "" {
-		return nil, nil
+		return newVaultK8SAuthMethodRefreshTokenWatcher(clients, c, doneCh)
 	}
 
 	unwrap := config.BoolVal(c.UnwrapToken)
@@ -76,7 +106,6 @@ func VaultTokenWatcher(
 
 	return watcher, nil
 }
-
 func watchTokenFile(
 	w *Watcher, tokenFile, raw_token string, unwrap bool, doneCh chan struct{},
 ) (func(), error) {

watch/vault_token_test.go

@@ -14,6 +14,8 @@ import (
 	"github.com/hashicorp/consul-template/config"
 	dep "github.com/hashicorp/consul-template/dependency"
 	"github.com/hashicorp/vault/api"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // approle auto-auth setup in watch_test.go, TestMain()
@@ -141,6 +143,35 @@ func TestVaultTokenWatcher(t *testing.T) {
 			// give it a chance to throw an error
 		}
 	})
+
+	t.Run("renew_kubernetes", func(t *testing.T) {
+		// Check that there is an attempt to refresh token.
+		testClients.Vault().SetToken(vaultToken)
+
+		_, err := testClients.Vault().Auth().Token().Create(
+			&api.TokenCreateRequest{
+				ID:        "c_token",
+				TTL:       "1m",
+				Renewable: config.Bool(true),
+			})
+		require.NoError(t, err)
+
+		conf := config.DefaultVaultConfig()
+		conf.Token = config.String("")
+		conf.RenewToken = config.Bool(true)
+		conf.K8SServiceAccountToken = config.String("any_k8s_token")
+
+		watcher, err := VaultTokenWatcher(testClients, conf, nil)
+		require.NoError(t, err)
+
+		defer watcher.Stop()
+
+		select {
+		case err := <-watcher.ErrCh():
+			assert.ErrorIs(t, err, dep.ErrLeaseExpired)
+		case <-time.After(time.Millisecond * 100):
+		}
+	})
 }
 
 func TestVaultTokenRefreshToken(t *testing.T) {