💥 [BREAKING] enable TLS if api key specified

client/client.go

@@ -1514,6 +1514,8 @@ func HistoryFromJSON(r io.Reader, options HistoryJSONOptions) (*historypb.Histor
 // Note, this uses a fixed header value for authentication. Many users that want
 // to rotate this value without reconnecting should use
 // [NewAPIKeyDynamicCredentials].
+//
+// Note, TLS is auto-enabled when API key is provided and TLS is not explicitly set/disabled.
 func NewAPIKeyStaticCredentials(apiKey string) Credentials {
 	return internal.NewAPIKeyStaticCredentials(apiKey)
 }
@@ -1528,6 +1530,8 @@ func NewAPIKeyStaticCredentials(apiKey string) Credentials {
 // "Authorization" header with "Bearer " + the given function result. If the
 // resulting string is non-empty, it will overwrite any "Authorization" header
 // that may be on the context or from existing header provider.
+//
+// Note, TLS is auto-enabled when API key is provided and TLS is not explicitly set/disabled.
 func NewAPIKeyDynamicCredentials(apiKeyCallback func(context.Context) (string, error)) Credentials {
 	return internal.NewAPIKeyDynamicCredentials(apiKeyCallback)
 }

internal/client.go

@@ -542,6 +542,12 @@ type (
 		// TLS configures connection level security credentials.
 		TLS *tls.Config
 
+		// TLSDisabled explicitly disables TLS. When true, TLS will not be used even
+		// if API key credentials are provided (which would normally auto-enable TLS).
+		// This is not recommended for production use as it sends credentials in plaintext.
+		// This option is mutually exclusive with TLS - an error will be returned if both are set.
+		TLSDisabled bool
+
 		// Authority specifies the value to be used as the :authority pseudo-header.
 		// This value only used when TLS is nil.
 		Authority string
@@ -990,6 +996,11 @@ func newClient(ctx context.Context, options ClientOptions, existing *WorkflowCli
 		options.Logger.Info("No logger configured for temporal client. Created default one.")
 	}
 
+	// Validate mutually exclusive TLS options
+	if options.ConnectionOptions.TLS != nil && options.ConnectionOptions.TLSDisabled {
+		return nil, fmt.Errorf("cannot set both TLS and TLSDisabled in ConnectionOptions")
+	}
+
 	if options.Credentials != nil {
 		if err := options.Credentials.applyToOptions(&options.ConnectionOptions); err != nil {
 			return nil, err
@@ -1210,7 +1221,13 @@ func NewAPIKeyDynamicCredentials(apiKeyCallback func(context.Context) (string, e
 	return apiKeyCredentials(apiKeyCallback)
 }
 
-func (apiKeyCredentials) applyToOptions(*ConnectionOptions) error { return nil }
+func (apiKeyCredentials) applyToOptions(opts *ConnectionOptions) error {
+	// Auto-enable TLS when API key is provided and TLS is not explicitly set/disabled
+	if opts.TLS == nil && !opts.TLSDisabled {
+		opts.TLS = &tls.Config{}
+	}
+	return nil
+}
 
 func (a apiKeyCredentials) gRPCInterceptor() grpc.UnaryClientInterceptor { return a.gRPCIntercept }
 

internal/credentials_test.go

@@ -0,0 +1,76 @@
+package internal
+
+import (
+	"context"
+	"crypto/tls"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestAPIKeyCredentials_TLSEnabledByDefaultWhenAPIKeyProvided(t *testing.T) {
+	creds := NewAPIKeyStaticCredentials("test-api-key")
+	opts := &ConnectionOptions{}
+
+	err := creds.applyToOptions(opts)
+	require.NoError(t, err)
+
+	// TLS should be auto-enabled when api_key is provided and tls not explicitly set
+	require.NotNil(t, opts.TLS)
+}
+
+func TestAPIKeyCredentials_TLSCanBeExplicitlyDisabledWithAPIKey(t *testing.T) {
+	// Test that TLS can be explicitly disabled using TLSDisabled field
+	creds := NewAPIKeyStaticCredentials("test-api-key")
+	opts := &ConnectionOptions{
+		TLSDisabled: true,
+	}
+
+	err := creds.applyToOptions(opts)
+	require.NoError(t, err)
+
+	// TLS should remain nil when TLSDisabled is true
+	require.Nil(t, opts.TLS)
+}
+
+func TestConnectionOptions_TLSDisabledByDefaultWithoutAPIKey(t *testing.T) {
+	// Test that TLS is disabled by default when no API key is provided
+	opts := &ConnectionOptions{}
+
+	// Without API key credentials, TLS should remain nil
+	require.Nil(t, opts.TLS)
+}
+
+func TestAPIKeyCredentials_ExplicitTLSConfigPreservedWithAPIKey(t *testing.T) {
+	// Test that explicit TLS configuration is preserved when API key is provided
+	tlsConfig := &tls.Config{
+		ServerName: "test-domain",
+		MinVersion: tls.VersionTLS12,
+	}
+
+	creds := NewAPIKeyStaticCredentials("test-api-key")
+	opts := &ConnectionOptions{
+		TLS: tlsConfig,
+	}
+
+	err := creds.applyToOptions(opts)
+	require.NoError(t, err)
+
+	// Explicit TLS config should be preserved
+	require.NotNil(t, opts.TLS)
+	require.Equal(t, "test-domain", opts.TLS.ServerName)
+	require.Equal(t, uint16(tls.VersionTLS12), opts.TLS.MinVersion)
+}
+
+func TestConnectionOptions_TLSAndTLSDisabledMutuallyExclusive(t *testing.T) {
+	// Test that setting both TLS and TLSDisabled returns an error
+	_, err := NewClient(context.Background(), ClientOptions{
+		HostPort: "localhost:7233",
+		ConnectionOptions: ConnectionOptions{
+			TLS:         &tls.Config{},
+			TLSDisabled: true,
+		},
+	})
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "cannot set both TLS and TLSDisabled")
+}

internal/grpc_dialer_test.go

@@ -446,6 +446,9 @@ func TestCredentialsAPIKey(t *testing.T) {
 	client, err := DialClient(context.Background(), ClientOptions{
 		HostPort:    srv.addr,
 		Credentials: NewAPIKeyStaticCredentials("my-api-key"),
+		ConnectionOptions: ConnectionOptions{
+			TLSDisabled: true, // Test server doesn't use TLS
+		},
 	})
 	require.NoError(t, err)
 	defer client.Close()
@@ -484,6 +487,9 @@ func TestCredentialsAPIKey(t *testing.T) {
 		Credentials: NewAPIKeyDynamicCredentials(func(ctx context.Context) (string, error) {
 			return "my-callback-api-key", nil
 		}),
+		ConnectionOptions: ConnectionOptions{
+			TLSDisabled: true,
+		},
 	})
 	require.NoError(t, err)
 	defer client.Close()