GODT-1381: Use in-memory cache in case local cache is unavailable

- change: refactor GUI notification object
- add: global bridge errors
- add: when cache on disk cannot be initialized fallback to memory cache
- add: show notification for CoD failure
- change: do not allow login to IMAP and SMTP when CoD init failed

internal/app/bridge/bridge.go

@@ -24,7 +24,7 @@ import (
 
 	"github.com/ProtonMail/proton-bridge/internal/api"
 	"github.com/ProtonMail/proton-bridge/internal/app/base"
-	"github.com/ProtonMail/proton-bridge/internal/bridge"
+	pkgBridge "github.com/ProtonMail/proton-bridge/internal/bridge"
 	"github.com/ProtonMail/proton-bridge/internal/config/settings"
 	pkgTLS "github.com/ProtonMail/proton-bridge/internal/config/tls"
 	"github.com/ProtonMail/proton-bridge/internal/constants"
@@ -46,6 +46,10 @@ const (
 	flagLogSMTP        = "log-smtp"
 	flagNoWindow       = "no-window"
 	flagNonInteractive = "noninteractive"
+
+	// Memory cache was estimated by empirical usage in past and it was set to 100MB.
+	// NOTE: This value must not be less than maximal size of one email (~30MB).
+	inMemoryCacheLimnit = 100 * (1 << 20)
 )
 
 func New(base *base.Base) *cli.App {
@@ -75,9 +79,9 @@ func run(b *base.Base, c *cli.Context) error { // nolint[funlen]
 		return err
 	}
 
-	cache, err := loadMessageCache(b)
+	cache, cacheErr := loadMessageCache(b)
-	if err != nil {
+	if cacheErr != nil {
-		return err
+		logrus.WithError(cacheErr).Error("Could not load local cache.")
 	}
 
 	builder := message.NewBuilder(
@@ -85,10 +89,14 @@ func run(b *base.Base, c *cli.Context) error { // nolint[funlen]
 		b.Settings.GetInt(settings.AttachmentWorkers),
 	)
 
-	bridge := bridge.New(b.Locations, b.Cache, b.Settings, b.SentryReporter, b.CrashHandler, b.Listener, cache, builder, b.CM, b.Creds, b.Updater, b.Versioner)
+	bridge := pkgBridge.New(b.Locations, b.Cache, b.Settings, b.SentryReporter, b.CrashHandler, b.Listener, cache, builder, b.CM, b.Creds, b.Updater, b.Versioner)
 	imapBackend := imap.NewIMAPBackend(b.CrashHandler, b.Listener, b.Cache, b.Settings, bridge)
 	smtpBackend := smtp.NewSMTPBackend(b.CrashHandler, b.Listener, b.Settings, bridge)
 
+	if cacheErr != nil {
+		bridge.AddError(pkgBridge.ErrLocalCacheUnavailable)
+	}
+
 	go func() {
 		defer b.CrashHandler.HandlePanic()
 		api.NewAPIServer(b.Settings, b.Listener).ListenAndServe()
@@ -248,13 +256,12 @@ func checkAndHandleUpdate(u types.Updater, f frontend.Frontend, autoUpdate bool)
 	f.NotifySilentUpdateInstalled()
 }
 
+// loadMessageCache loads local cache in case it is enabled in settings and available.
+// In any other case it is returning in-memory cache. Could also return an error in case
+// local cache is enabled but unavailable (in-memory cache will be returned nevertheless).
 func loadMessageCache(b *base.Base) (cache.Cache, error) {
 	if !b.Settings.GetBool(settings.CacheEnabledKey) {
-		// Memory cache was estimated by empirical usage in past and it
+		return cache.NewInMemoryCache(inMemoryCacheLimnit), nil
-		// was set to 100MB.
-		// NOTE: This value must not be less than maximal size of one
-		// email (~30MB).
-		return cache.NewInMemoryCache(100 << 20), nil
 	}
 
 	var compressor cache.Compressor
@@ -283,10 +290,16 @@ func loadMessageCache(b *base.Base) (cache.Cache, error) {
 	// build jobs.
 	store.SetBuildAndCacheJobLimit(b.Settings.GetInt(settings.CacheConcurrencyWrite))
 
-	return cache.NewOnDiskCache(path, compressor, cache.Options{
+	messageCache, err := cache.NewOnDiskCache(path, compressor, cache.Options{
 		MinFreeAbs:      uint64(b.Settings.GetInt(settings.CacheMinFreeAbsKey)),
 		MinFreeRat:      b.Settings.GetFloat64(settings.CacheMinFreeRatKey),
 		ConcurrentRead:  b.Settings.GetInt(settings.CacheConcurrencyRead),
 		ConcurrentWrite: b.Settings.GetInt(settings.CacheConcurrencyWrite),
 	})
+
+	if err != nil {
+		return cache.NewInMemoryCache(inMemoryCacheLimnit), err
+	}
+
+	return messageCache, nil
 }

internal/bridge/bridge.go

@@ -19,6 +19,7 @@
 package bridge
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"time"
@@ -40,6 +41,8 @@ import (
 
 var log = logrus.WithField("pkg", "bridge") //nolint[gochecknoglobals]
 
+var ErrLocalCacheUnavailable = errors.New("local cache is unavailable")
+
 type Bridge struct {
 	*users.Users
 
@@ -49,6 +52,8 @@ type Bridge struct {
 	updater       Updater
 	versioner     Versioner
 	cacheProvider CacheProvider
+	// Bridge's global errors list.
+	errors []error
 }
 
 func New(
@@ -241,3 +246,36 @@ func (b *Bridge) SetProxyAllowed(proxyAllowed bool) {
 func (b *Bridge) GetProxyAllowed() bool {
 	return b.settings.GetBool(settings.AllowProxyKey)
 }
+
+// AddError add an error to a global error list if it does not contain it yet. Adding nil is noop.
+func (b *Bridge) AddError(err error) {
+	if err == nil {
+		return
+	}
+	if b.HasError(err) {
+		return
+	}
+
+	b.errors = append(b.errors, err)
+}
+
+// DelError removes an error from global error list.
+func (b *Bridge) DelError(err error) {
+	for idx, val := range b.errors {
+		if val == err {
+			b.errors = append(b.errors[:idx], b.errors[idx+1:]...)
+			return
+		}
+	}
+}
+
+// HasError returnes true if global error list contains an err.
+func (b *Bridge) HasError(err error) bool {
+	for _, val := range b.errors {
+		if val == err {
+			return true
+		}
+	}
+
+	return false
+}

internal/frontend/qml/Banner.qml

@@ -80,13 +80,13 @@ Popup {
                     }
 
                     switch (root.notification.type) {
-                        case Notification.NotificationType.Info:
+                    case Notification.NotificationType.Info:
                         return root.colorScheme.signal_info
-                        case Notification.NotificationType.Success:
+                    case Notification.NotificationType.Success:
                         return root.colorScheme.signal_success
-                        case Notification.NotificationType.Warning:
+                    case Notification.NotificationType.Warning:
                         return root.colorScheme.signal_warning
-                        case Notification.NotificationType.Danger:
+                    case Notification.NotificationType.Danger:
                         return root.colorScheme.signal_danger
                     }
                 }
@@ -118,13 +118,13 @@ Popup {
                         }
 
                         switch (root.notification.type) {
-                            case Notification.NotificationType.Info:
+                        case Notification.NotificationType.Info:
                             return "./icons/ic-info-circle-filled.svg"
-                            case Notification.NotificationType.Success:
+                        case Notification.NotificationType.Success:
                             return "./icons/ic-info-circle-filled.svg"
-                            case Notification.NotificationType.Warning:
+                        case Notification.NotificationType.Warning:
                             return "./icons/ic-exclamation-circle-filled.svg"
-                            case Notification.NotificationType.Danger:
+                        case Notification.NotificationType.Danger:
                             return "./icons/ic-exclamation-circle-filled.svg"
                         }
                     }
@@ -136,7 +136,7 @@ Popup {
                     Layout.alignment: Qt.AlignVCenter
 
                     color: root.colorScheme.text_invert
-                    text: root.notification ? root.notification.text : ""
+                    text: root.notification ? root.notification.description : ""
 
                     wrapMode: Text.WordWrap
                 }
@@ -152,13 +152,13 @@ Popup {
                 }
 
                 switch (root.notification.type) {
-                    case Notification.NotificationType.Info:
+                case Notification.NotificationType.Info:
                     return root.colorScheme.signal_info_active
-                    case Notification.NotificationType.Success:
+                case Notification.NotificationType.Success:
                     return root.colorScheme.signal_success_active
-                    case Notification.NotificationType.Warning:
+                case Notification.NotificationType.Warning:
                     return root.colorScheme.signal_warning_active
-                    case Notification.NotificationType.Danger:
+                case Notification.NotificationType.Danger:
                     return root.colorScheme.signal_danger_active
                 }
             }
@@ -190,22 +190,22 @@ Popup {
                         var active
 
                         switch (root.notification.type) {
-                            case Notification.NotificationType.Info:
+                        case Notification.NotificationType.Info:
                             norm = root.colorScheme.signal_info
                             hover = root.colorScheme.signal_info_hover
                             active = root.colorScheme.signal_info_active
                             break;
-                            case Notification.NotificationType.Success:
+                        case Notification.NotificationType.Success:
                             norm = root.colorScheme.signal_success
                             hover = root.colorScheme.signal_success_hover
                             active = root.colorScheme.signal_success_active
                             break;
-                            case Notification.NotificationType.Warning:
+                        case Notification.NotificationType.Warning:
                             norm = root.colorScheme.signal_warning
                             hover = root.colorScheme.signal_warning_hover
                             active = root.colorScheme.signal_warning_active
                             break;
-                            case Notification.NotificationType.Danger:
+                        case Notification.NotificationType.Danger:
                             norm = root.colorScheme.signal_danger
                             hover = root.colorScheme.signal_danger_hover
                             active = root.colorScheme.signal_danger_active

internal/frontend/qml/Bridge.qml

@@ -52,6 +52,13 @@ QtObject {
         onVisibleChanged: {
             backend.dockIconVisible = visible
         }
+
+        Connections {
+            target: root.backend
+            onCacheUnavailable: {
+                mainWindow.showAndRise()
+            }
+        }
     }
 
     property StatusWindow _statusWindow: StatusWindow {

internal/frontend/qml/NotificationDialog.qml

@@ -55,12 +55,12 @@ Dialog {
                 }
 
                 switch (root.notification.type) {
-                    case Notification.NotificationType.Info:
+                case Notification.NotificationType.Info:
                     return "./icons/ic-info.svg"
-                    case Notification.NotificationType.Success:
+                case Notification.NotificationType.Success:
                     return "./icons/ic-success.svg"
-                    case Notification.NotificationType.Warning:
+                case Notification.NotificationType.Warning:
-                    case Notification.NotificationType.Danger:
+                case Notification.NotificationType.Danger:
                     return "./icons/ic-alert.svg"
                 }
             }
@@ -70,7 +70,7 @@ Dialog {
             Layout.alignment: Qt.AlignHCenter
             Layout.bottomMargin: 8
             colorScheme: root.colorScheme
-            text: root.notification.text
+            text: root.notification.title
             type: Label.LabelType.Title
         }
 

internal/frontend/qml/Notifications/Notification.qml

@@ -30,8 +30,13 @@ QtObject {
         Danger = 3
     }
 
-    property string text
+    // title is used in dialogs only
+    property string title
+    // description is used in banners and in dialogs as description
     property string description
+    // brief is used in status view only
+    property string brief
+
     property string icon
     property list<Action> action
     property int type

internal/frontend/qml/Notifications/Notifications.qml

@@ -74,7 +74,8 @@ QtObject {
 
     // Connection
     property Notification noInternet: Notification {
-        text: qsTr("No connection")
+        description: qsTr("Bridge is not able to contact the server, please check your internet connection.")
+        brief: qsTr("No connection")
         icon: "./icons/ic-no-connection.svg"
         type: Notification.NotificationType.Danger
         group: Notifications.Group.Connection
@@ -93,8 +94,9 @@ QtObject {
 
     // Updates
     property Notification updateManualReady: Notification {
-        text: qsTr("Update to Bridge") + " " + (data ? data.version : "")
+        title: qsTr("Update to Bridge %1").arg(data ? data.version : "")
         description: qsTr("A new version of ProtonMail Bridge is available. See what's changed.")
+        brief: qsTr("Update available. (See what's new.)")
         icon: "./icons/ic-info-circle-filled.svg"
         type: Notification.NotificationType.Info
         group: Notifications.Group.Update | Notifications.Group.Dialogs
@@ -135,7 +137,8 @@ QtObject {
     }
 
     property Notification updateManualRestartNeeded: Notification {
-        text: qsTr("Bridge update is ready")
+        description: qsTr("Bridge update is ready")
+        brief: description
         icon: "./icons/ic-info-circle-filled.svg"
         type: Notification.NotificationType.Info
         group: Notifications.Group.Update
@@ -158,7 +161,8 @@ QtObject {
     }
 
     property Notification updateManualError: Notification {
-        text: qsTr("Bridge couldn’t update. Please update manually.")
+        description: qsTr("Bridge couldn’t update")
+        brief: description
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Update
@@ -190,8 +194,9 @@ QtObject {
     }
 
     property Notification updateForce: Notification {
-        text: qsTr("Update to ProtonMail Bridge") + " " + (data ? data.version : "")
+        title: qsTr("Update to Bridge %1").arg(data ? data.version : "")
         description: qsTr("This version of Bridge is no longer supported, please update.")
+        brief: qsTr("Bridge is outdated")
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Danger
         group: Notifications.Group.Update | Notifications.Group.Dialogs
@@ -234,8 +239,9 @@ QtObject {
     }
 
     property Notification updateForceError: Notification {
-        text: qsTr("Bridge coudn’t update")
+        title: qsTr("Bridge coudn’t update")
-        description: qsTr("You must update manually.")
+        description: qsTr("You must update manually. Go to: https:/protonmail.com/bridge/download")
+        brief: title
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Danger
         group: Notifications.Group.Update | Notifications.Group.Dialogs
@@ -269,7 +275,8 @@ QtObject {
     }
 
     property Notification updateSilentRestartNeeded: Notification {
-        text: qsTr("Bridge update is ready")
+        description: qsTr("Bridge update is ready")
+        brief: description
         icon: "./icons/ic-info-circle-filled.svg"
         type: Notification.NotificationType.Info
         group: Notifications.Group.Update
@@ -292,7 +299,8 @@ QtObject {
     }
 
     property Notification updateSilentError: Notification {
-        text: qsTr("Bridge couldn’t update")
+        description: qsTr("Bridge couldn’t update")
+        brief: description
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Update
@@ -315,7 +323,7 @@ QtObject {
     }
 
     property Notification updateIsLatestVersion: Notification {
-        text: qsTr("Bridge is up to date")
+        description: qsTr("Bridge is up to date")
         icon: "./icons/ic-info-circle-filled.svg"
         type: Notification.NotificationType.Info
         group: Notifications.Group.Update
@@ -337,7 +345,7 @@ QtObject {
     }
 
     property Notification enableBeta: Notification {
-        text: qsTr("Enable Beta access")
+        title: qsTr("Enable Beta access")
         description: qsTr("Be the first to get new updates and use new features. Bridge will update to the latest beta version.")
         icon: "./icons/ic-info-circle-filled.svg"
         type: Notification.NotificationType.Info
@@ -370,7 +378,7 @@ QtObject {
 
     // login
     property Notification loginConnectionError: Notification {
-        text: qsTr("Bridge is not able to contact the server, please check your internet connection.")
+        description: qsTr("Bridge is not able to contact the server, please check your internet connection.")
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Danger
         group: Notifications.Group.Configuration
@@ -393,7 +401,7 @@ QtObject {
     }
 
     property Notification onlyPaidUsers: Notification {
-        text: qsTr("Bridge is exclusive to our paid plans. Upgrade your account to use Bridge.")
+        description: qsTr("Bridge is exclusive to our paid plans. Upgrade your account to use Bridge.")
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Danger
         group: Notifications.Group.Configuration
@@ -416,7 +424,7 @@ QtObject {
     }
 
     property Notification alreadyLoggedIn: Notification {
-        text: qsTr("This account is already signed it.")
+        description: qsTr("This account is already signed it.")
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Info
         group: Notifications.Group.Configuration
@@ -440,7 +448,7 @@ QtObject {
 
     // Bug reports
     property Notification bugReportSendSuccess: Notification {
-        text: qsTr("Thank you for the report. We'll get back to you as soon as we can.")
+        description: qsTr("Thank you for the report. We'll get back to you as soon as we can.")
         icon: "./icons/ic-info-circle-filled.svg"
         type: Notification.NotificationType.Success
         group: Notifications.Group.Configuration
@@ -463,7 +471,7 @@ QtObject {
     }
 
     property Notification bugReportSendError: Notification {
-        text: qsTr("Report could not be sent. Try again or email us directly.")
+        description: qsTr("Report could not be sent. Try again or email us directly.")
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Danger
         group: Notifications.Group.Configuration
@@ -485,8 +493,9 @@ QtObject {
 
     // Cache
     property Notification cacheUnavailable: Notification {
-        text: qsTr("Cache location is unavailable")
+        title: qsTr("Cache location is unavailable")
         description: qsTr("Check the directory or change it in your settings.")
+        brief: qsTr("The current cache location is unavailable. Check the directory or change it in your settings.")
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Configuration | Notifications.Group.Dialogs
 
@@ -516,7 +525,7 @@ QtObject {
     }
 
     property Notification cacheCantMove: Notification {
-        text: qsTr("Can’t move cache")
+        title: qsTr("Can’t move cache")
         description: qsTr("The location you have selected is not available. Make sure you have enough free space or choose another location.")
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Configuration | Notifications.Group.Dialogs
@@ -546,7 +555,7 @@ QtObject {
     }
 
     property Notification cacheLocationChangeSuccess: Notification {
-        text: qsTr("Cache location successfully changed")
+        description: qsTr("Cache location successfully changed")
         icon: "./icons/ic-info-circle-filled.svg"
         type: Notification.NotificationType.Success
         group: Notifications.Group.Configuration
@@ -571,7 +580,8 @@ QtObject {
 
     // Other
     property Notification accountChanged: Notification {
-        text: qsTr("The address list for your account has changed")
+        description: qsTr("The address list for .... account has changed. You need to reconfigure your email client.")
+        brief: qsTr("The address list for your account has changed. Reconfigure your email client.")
         icon: "./icons/ic-exclamation-circle-filled.svg"
         type: Notification.NotificationType.Danger
         group: Notifications.Group.Configuration
@@ -586,8 +596,9 @@ QtObject {
     }
 
     property Notification diskFull: Notification {
-        text: qsTr("Your disk is almost full")
+        title: qsTr("Your disk is almost full")
         description: qsTr("Quit Bridge and free disk space or disable the local cache (not recommended).")
+        brief: qsTr("Your disk is almost full. Free disk space or disable the local cache.")
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Configuration | Notifications.Group.Dialogs
 
@@ -617,8 +628,8 @@ QtObject {
     }
 
     property Notification enableSplitMode: Notification {
-        text: qsTr("Enable split mode?")
+        title: qsTr("Enable split mode?")
-        description: qsTr("Changing between split and combined address mode will require you to delete your accounts(s) from your email client and begin the setup process from scratch.")
+        description: qsTr("Changing between split and combined address mode will require you to delete your account(s) from your email client and begin the setup process from scratch.")
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Configuration | Notifications.Group.Dialogs
 
@@ -632,7 +643,6 @@ QtObject {
             }
         }
 
-
         Connections {
             target: (root && root.enableSplitMode && root.enableSplitMode.user ) ? root.enableSplitMode.user : null
             onToggleSplitModeFinished: {
@@ -664,7 +674,7 @@ QtObject {
     }
 
     property Notification disableLocalCache: Notification {
-        text: qsTr("Disable local cache?")
+        title: qsTr("Disable local cache?")
         description: qsTr("This action will clear your local cache, including locally stored messages. Bridge will restart.")
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Configuration | Notifications.Group.Dialogs
@@ -676,7 +686,6 @@ QtObject {
             }
         }
 
-
         Connections {
             target: root.backend
             onChangeLocalCacheFinished: {
@@ -708,7 +717,7 @@ QtObject {
     }
 
     property Notification enableLocalCache: Notification {
-        text: qsTr("Enable local cache?")
+        title: qsTr("Enable local cache")
         description: qsTr("Bridge will restart.")
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Configuration | Notifications.Group.Dialogs
@@ -723,7 +732,6 @@ QtObject {
             }
         }
 
-
         Connections {
             target: root.backend
             onChangeLocalCacheFinished: {
@@ -755,7 +763,7 @@ QtObject {
     }
 
     property Notification resetBridge: Notification {
-        text: qsTr("Reset Bridge?")
+        title: qsTr("Reset Bridge?")
         description: qsTr("This will clear your accounts, preferences, and cached data. You will need to reconfigure your email client. Bridge will automatically restart.")
         type: Notification.NotificationType.Warning
         group: Notifications.Group.Configuration | Notifications.Group.Dialogs
@@ -769,7 +777,6 @@ QtObject {
             }
         }
 
-
         Connections {
             target: root.backend
             onResetFinished: {

internal/frontend/qml/Status.qml

@@ -56,22 +56,22 @@ Item {
             }
 
             image.source = topmost.icon
-            label.text = topmost.text
+            label.text = topmost.brief
 
             switch (topmost.type) {
-                case Notification.NotificationType.Danger:
+            case Notification.NotificationType.Danger:
                 image.color = root.colorScheme.signal_danger
                 label.color = root.colorScheme.signal_danger
                 break;
-                case Notification.NotificationType.Warning:
+            case Notification.NotificationType.Warning:
                 image.color = root.colorScheme.signal_warning
                 label.color = root.colorScheme.signal_warning
                 break;
-                case Notification.NotificationType.Success:
+            case Notification.NotificationType.Success:
                 image.color = root.colorScheme.signal_success
                 label.color = root.colorScheme.signal_success
                 break;
-                case Notification.NotificationType.Info:
+            case Notification.NotificationType.Info:
                 image.color = root.colorScheme.signal_info
                 label.color = root.colorScheme.signal_info
                 break;

internal/frontend/qml/StatusWindow.qml

@@ -128,7 +128,7 @@ Window {
                         Layout.topMargin: 12
                         Layout.bottomMargin: 12
 
-                        visible: (statusItem.activeNotification && statusItem.activeNotification.action) ? true : false
+                        visible: statusItem.activeNotification && statusItem.activeNotification.action.length > 0
                         action: statusItem.activeNotification && statusItem.activeNotification.action.length > 0 ? statusItem.activeNotification.action[0] : null
                     }
                 }

internal/frontend/qt/frontend_events.go

@@ -15,6 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
 
+//go:build build_qt
 // +build build_qt
 
 // Package qt provides communication between Qt/QML frontend and Go backend
@@ -23,12 +24,18 @@ package qt
 import (
 	"strings"
 
+	"github.com/ProtonMail/proton-bridge/internal/bridge"
 	"github.com/ProtonMail/proton-bridge/internal/events"
 )
 
 func (f *FrontendQt) watchEvents() {
 	f.WaitUntilFrontendIsReady()
 
+	// First we check bridge global errors for any error that should be shown on GUI.
+	if f.bridge.HasError(bridge.ErrLocalCacheUnavailable) {
+		f.qml.CacheUnavailable()
+	}
+
 	errorCh := f.eventListener.ProvideChannel(events.ErrorEvent)
 	credentialsErrorCh := f.eventListener.ProvideChannel(events.CredentialsErrorEvent)
 	noActiveKeyForRecipientCh := f.eventListener.ProvideChannel(events.NoActiveKeyForRecipientEvent)

internal/frontend/types/types.go

@@ -86,6 +86,7 @@ type Bridger interface {
 	SetUpdateChannel(updater.UpdateChannel)
 	GetKeychainApp() string
 	SetKeychainApp(keychain string)
+	HasError(err error) bool
 }
 
 type bridgeWrap struct {

internal/imap/backend.go

@@ -39,6 +39,7 @@ import (
 	"github.com/ProtonMail/proton-bridge/internal/bridge"
 	"github.com/ProtonMail/proton-bridge/internal/config/settings"
 	"github.com/ProtonMail/proton-bridge/internal/events"
+	"github.com/ProtonMail/proton-bridge/internal/users"
 	"github.com/ProtonMail/proton-bridge/pkg/listener"
 	"github.com/emersion/go-imap"
 	goIMAPBackend "github.com/emersion/go-imap/backend"
@@ -168,6 +169,10 @@ func (ib *imapBackend) Login(_ *imap.ConnInfo, username, password string) (goIMA
 	// Called from go-imap in goroutines - we need to handle panics for each function.
 	defer ib.panicHandler.HandlePanic()
 
+	if ib.bridge.HasError(bridge.ErrLocalCacheUnavailable) {
+		return nil, users.ErrLoggedOutUser
+	}
+
 	imapUser, err := ib.getUser(username)
 	if err != nil {
 		log.WithError(err).Warn("Cannot get user")

internal/imap/bridge.go

@@ -30,6 +30,7 @@ type cacheProvider interface {
 
 type bridger interface {
 	GetUser(query string) (bridgeUser, error)
+	HasError(err error) bool
 }
 
 type bridgeUser interface {

internal/smtp/backend.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/ProtonMail/proton-bridge/internal/bridge"
 	"github.com/ProtonMail/proton-bridge/internal/config/settings"
+	"github.com/ProtonMail/proton-bridge/internal/users"
 	"github.com/ProtonMail/proton-bridge/pkg/confirmer"
 	"github.com/ProtonMail/proton-bridge/pkg/listener"
 	goSMTPBackend "github.com/emersion/go-smtp"
@@ -77,6 +78,11 @@ func newSMTPBackend(
 func (sb *smtpBackend) Login(_ *goSMTPBackend.ConnectionState, username, password string) (goSMTPBackend.Session, error) {
 	// Called from go-smtp in goroutines - we need to handle panics for each function.
 	defer sb.panicHandler.HandlePanic()
+
+	if sb.bridge.HasError(bridge.ErrLocalCacheUnavailable) {
+		return nil, users.ErrLoggedOutUser
+	}
+
 	username = strings.ToLower(username)
 
 	user, err := sb.bridge.GetUser(username)

internal/smtp/bridge.go

@@ -25,6 +25,7 @@ import (
 
 type bridger interface {
 	GetUser(query string) (bridgeUser, error)
+	HasError(err error) bool
 }
 
 type bridgeUser interface {