chore: Remove panics from SetGluonDir

internal/bridge/bridge.go

@@ -371,14 +371,12 @@ func (bridge *Bridge) init(tlsReporter TLSReporter) error {
 		})
 	})
 
-	// Attempt to lazy load users when triggered. Only load once.
+	// We need to load users before we can start the IMAP and SMTP servers.
-	var loaded bool
+	// We must only start the servers once.
-	bridge.goLoad = bridge.tasks.Trigger(func(ctx context.Context) {
+	var once sync.Once
-		if loaded {
-			logrus.Debug("All users are already loaded, skipping")
-			return
-		}
 
+	// Attempt to load users from the vault when triggered.
+	bridge.goLoad = bridge.tasks.Trigger(func(ctx context.Context) {
 		logrus.Info("Loading users")
 
 		if err := bridge.loadUsers(ctx); err != nil {
@@ -389,15 +387,15 @@ func (bridge *Bridge) init(tlsReporter TLSReporter) error {
 		bridge.publish(events.AllUsersLoaded{})
 
 		// Once all users have been loaded, start the bridge's IMAP and SMTP servers.
-		if err := bridge.serveIMAP(); err != nil {
+		once.Do(func() {
-			logrus.WithError(err).Error("Failed to start IMAP server")
+			if err := bridge.serveIMAP(); err != nil {
-		}
+				logrus.WithError(err).Error("Failed to start IMAP server")
+			}
 
-		if err := bridge.serveSMTP(); err != nil {
+			if err := bridge.serveSMTP(); err != nil {
-			logrus.WithError(err).Error("Failed to start SMTP server")
+				logrus.WithError(err).Error("Failed to start SMTP server")
-		}
+			}
-
+		})
-		loaded = true
 	})
 	defer bridge.goLoad()
 

internal/bridge/imap.go

@@ -46,7 +46,7 @@ const (
 )
 
 func (bridge *Bridge) serveIMAP() error {
-	if port, err := func() (int, error) {
+	port, err := func() (int, error) {
 		if bridge.imapServer == nil {
 			return 0, fmt.Errorf("no IMAP server instance running")
 		}
@@ -69,19 +69,21 @@ func (bridge *Bridge) serveIMAP() error {
 		}
 
 		return getPort(imapListener.Addr()), nil
-	}(); err != nil {
+	}()
+
+	if err != nil {
 		bridge.publish(events.IMAPServerError{
 			Error: err,
 		})
 
 		return err
-	} else {
-		bridge.publish(events.IMAPServerReady{
-			Port: port,
-		})
-
-		return nil
 	}
+
+	bridge.publish(events.IMAPServerReady{
+		Port: port,
+	})
+
+	return nil
 }
 
 func (bridge *Bridge) restartIMAP() error {

internal/bridge/settings.go

@@ -131,26 +131,21 @@ func (bridge *Bridge) SetGluonDir(ctx context.Context, newGluonDir string) error
 			return fmt.Errorf("new gluon dir is the same as the old one")
 		}
 
-		if err := bridge.stopEventLoops(); err != nil {
+		if err := bridge.closeIMAP(context.Background()); err != nil {
-			return err
+			return fmt.Errorf("failed to close IMAP: %w", err)
 		}
-		defer func() {
-			err := bridge.startEventLoops(ctx)
-			if err != nil {
-				panic(err)
-			}
-		}()
 
 		if err := bridge.moveGluonCacheDir(currentGluonDir, newGluonDir); err != nil {
 			logrus.WithError(err).Error("failed to move GluonCacheDir")
+
 			if err := bridge.vault.SetGluonDir(currentGluonDir); err != nil {
-				panic(err)
+				return fmt.Errorf("failed to revert GluonCacheDir: %w", err)
 			}
 		}
 
 		gluonDataDir, err := bridge.GetGluonDataDir()
 		if err != nil {
-			panic(fmt.Errorf("failed to get Gluon Database directory: %w", err))
+			return fmt.Errorf("failed to get Gluon Database directory: %w", err)
 		}
 
 		imapServer, err := newIMAPServer(
@@ -166,11 +161,21 @@ func (bridge *Bridge) SetGluonDir(ctx context.Context, newGluonDir string) error
 			bridge.uidValidityGenerator,
 		)
 		if err != nil {
-			panic(fmt.Errorf("failed to create new IMAP server: %w", err))
+			return fmt.Errorf("failed to create new IMAP server: %w", err)
 		}
 
 		bridge.imapServer = imapServer
 
+		for _, user := range bridge.users {
+			if err := bridge.addIMAPUser(ctx, user); err != nil {
+				return fmt.Errorf("failed to add users to new IMAP server: %w", err)
+			}
+		}
+
+		if err := bridge.serveIMAP(); err != nil {
+			return fmt.Errorf("failed to serve IMAP: %w", err)
+		}
+
 		return nil
 	}, bridge.usersLock)
 }
@@ -192,34 +197,6 @@ func (bridge *Bridge) moveGluonCacheDir(oldGluonDir, newGluonDir string) error {
 	return nil
 }
 
-func (bridge *Bridge) stopEventLoops() error {
-	if err := bridge.closeIMAP(context.Background()); err != nil {
-		return fmt.Errorf("failed to close IMAP: %w", err)
-	}
-
-	if err := bridge.closeSMTP(); err != nil {
-		return fmt.Errorf("failed to close SMTP: %w", err)
-	}
-	return nil
-}
-
-func (bridge *Bridge) startEventLoops(ctx context.Context) error {
-	for _, user := range bridge.users {
-		if err := bridge.addIMAPUser(ctx, user); err != nil {
-			return fmt.Errorf("failed to add users to new IMAP server: %w", err)
-		}
-	}
-
-	if err := bridge.serveIMAP(); err != nil {
-		panic(fmt.Errorf("failed to serve IMAP: %w", err))
-	}
-
-	if err := bridge.serveSMTP(); err != nil {
-		panic(fmt.Errorf("failed to serve SMTP: %w", err))
-	}
-	return nil
-}
-
 func (bridge *Bridge) GetProxyAllowed() bool {
 	return bridge.vault.GetProxyAllowed()
 }

internal/bridge/smtp.go

@@ -32,7 +32,7 @@ import (
 )
 
 func (bridge *Bridge) serveSMTP() error {
-	if port, err := func() (int, error) {
+	port, err := func() (int, error) {
 		logrus.Info("Starting SMTP server")
 
 		smtpListener, err := newListener(bridge.vault.GetSMTPPort(), bridge.vault.GetSMTPSSL(), bridge.tlsConfig)
@@ -53,19 +53,21 @@ func (bridge *Bridge) serveSMTP() error {
 		}
 
 		return getPort(smtpListener.Addr()), nil
-	}(); err != nil {
+	}()
+
+	if err != nil {
 		bridge.publish(events.SMTPServerError{
 			Error: err,
 		})
 
 		return err
-	} else {
-		bridge.publish(events.SMTPServerReady{
-			Port: port,
-		})
-
-		return nil
 	}
+
+	bridge.publish(events.SMTPServerReady{
+		Port: port,
+	})
+
+	return nil
 }
 
 func (bridge *Bridge) restartSMTP() error {

internal/events/serve.go

@@ -1,3 +1,20 @@
+// Copyright (c) 2023 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
 package events
 
 import "fmt"