feat(BRIDGE-268): add kill switch feature flag for the IMAP AUTHENTICATE command.

internal/bridge/imap.go

@@ -26,6 +26,7 @@ import (
 	imapEvents "github.com/ProtonMail/gluon/events"
 	"github.com/ProtonMail/proton-bridge/v3/internal/events"
 	"github.com/ProtonMail/proton-bridge/v3/internal/services/imapsmtpserver"
+	"github.com/ProtonMail/proton-bridge/v3/internal/unleash"
 	"github.com/ProtonMail/proton-bridge/v3/internal/useragent"
 	"github.com/sirupsen/logrus"
 )
@@ -93,6 +94,10 @@ func (b *bridgeIMAPSettings) LogServer() bool {
 	return b.b.logIMAPServer
 }
 
+func (b *bridgeIMAPSettings) DisableIMAPAuthenticate() bool {
+	return b.b.unleashService.GetFlagValue(unleash.IMAPAuthenticateCommandDisabled)
+}
+
 func (b *bridgeIMAPSettings) Port() int {
 	return b.b.vault.GetIMAPPort()
 }

internal/services/imapsmtpserver/imap.go

@@ -49,6 +49,7 @@ type IMAPSettingsProvider interface {
 	Port() int
 	SetPort(int) error
 	UseSSL() bool
+	DisableIMAPAuthenticate() bool
 	CacheDirectory() string
 	DataDirectory() (string, error)
 	SetCacheDirectory(string) error
@@ -74,6 +75,7 @@ func newIMAPServer(
 	tlsConfig *tls.Config,
 	reporter reporter.Reporter,
 	logClient, logServer bool,
+	disableIMAPAuthenticate bool,
 	eventPublisher IMAPEventPublisher,
 	tasks *async.Group,
 	uidValidityGenerator imap.UIDValidityGenerator,
@@ -113,7 +115,7 @@ func newIMAPServer(
 		imapServerLog = io.Discard
 	}
 
-	imapServer, err := gluon.New(
+	options := []gluon.Option{
 		gluon.WithTLS(tlsConfig),
 		gluon.WithDataDir(gluonCacheDir),
 		gluon.WithDatabaseDir(gluonConfigDir),
@@ -124,7 +126,13 @@ func newIMAPServer(
 		gluon.WithUIDValidityGenerator(uidValidityGenerator),
 		gluon.WithPanicHandler(panicHandler),
 		gluon.WithObservabilitySender(observability.NewAdapter(observabilitySender), int(observability.GluonImapError), int(observability.GluonMessageError), int(observability.GluonOtherError)),
-	)
+	}
+
+	if disableIMAPAuthenticate {
+		options = append(options, gluon.WithDisableIMAPAuthenticate())
+	}
+
+	imapServer, err := gluon.New(options...)
 	if err != nil {
 		return nil, err
 	}

internal/services/imapsmtpserver/service.go

@@ -451,6 +451,7 @@ func (sm *Service) createIMAPServer(ctx context.Context) (*gluon.Server, error)
 		sm.reporter,
 		sm.imapSettings.LogClient(),
 		sm.imapSettings.LogServer(),
+		sm.imapSettings.DisableIMAPAuthenticate(),
 		sm.imapSettings.EventPublisher(),
 		sm.tasks,
 		sm.uidValidityGenerator,

internal/services/notifications/service.go

@@ -50,7 +50,6 @@ type Service struct {
 }
 
 const bitfieldRegexPattern = `^\\\d+`
-const disableNotificationsKillSwitch = "InboxBridgeEventLoopNotificationDisabled"
 
 func NewService(userID string, service userevents.Subscribable, eventPublisher events.EventPublisher, store *Store,
 	getFlagFn unleash.GetFlagValueFn, observabilitySender observability.Sender) *Service {
@@ -103,7 +102,7 @@ func (s *Service) run(ctx context.Context) {
 }
 
 func (s *Service) HandleNotificationEvents(ctx context.Context, notificationEvents []proton.NotificationEvent) error {
-	if s.getFlagValueFn(disableNotificationsKillSwitch) {
+	if s.getFlagValueFn(unleash.EventLoopNotificationDisabled) {
 		s.log.Info("Received notification events. Skipping as kill switch is enabled.")
 		return nil
 	}

internal/unleash/service.go

@@ -36,6 +36,11 @@ var pollJitter = 2 * time.Minute  //nolint:gochecknoglobals
 
 const filename = "unleash_flags"
 
+const (
+	EventLoopNotificationDisabled   = "InboxBridgeEventLoopNotificationDisabled"
+	IMAPAuthenticateCommandDisabled = "InboxBridgeImapAuthenticateCommandDisabled"
+)
+
 type requestFeaturesFn func(ctx context.Context) (proton.FeatureFlagResult, error)
 type GetFlagValueFn func(key string) bool