Maintenance: rework main function

cmd/gluetun/main.go

@@ -53,42 +53,79 @@ func main() {
 		Commit:    commit,
 		BuildDate: buildDate,
 	}
+
 	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+
+	logger, err := logging.NewLogger(logging.ConsoleEncoding, logging.InfoLevel)
+	if err != nil {
+		fmt.Println(err)
+		nativeos.Exit(1)
+	}
+
 	args := nativeos.Args
 	os := os.New()
 	osUser := user.New()
 	unix := unix.New()
 	cli := cli.New()
-	nativeos.Exit(_main(ctx, buildInfo, args, os, osUser, unix, cli))
+
+	errorCh := make(chan error)
+	go func() {
+		errorCh <- _main(ctx, buildInfo, args, logger, os, osUser, unix, cli)
+	}()
+
+	signalsCh := make(chan nativeos.Signal, 1)
+	signal.Notify(signalsCh,
+		syscall.SIGINT,
+		syscall.SIGTERM,
+		nativeos.Interrupt,
+	)
+
+	select {
+	case signal := <-signalsCh:
+		logger.Warn("Caught OS signal %s, shutting down", signal)
+	case err := <-errorCh:
+		logger.Error(err)
+		close(errorCh)
+	}
+
+	cancel()
+
+	const shutdownGracePeriod = 5 * time.Second
+	timer := time.NewTimer(shutdownGracePeriod)
+	select {
+	case <-errorCh:
+		if !timer.Stop() {
+			<-timer.C
+		}
+		logger.Info("Shutdown successful")
+	case <-timer.C:
+		logger.Warn("Shutdown timed out")
+	}
+
+	nativeos.Exit(1)
 }
 
 //nolint:gocognit,gocyclo
 func _main(background context.Context, buildInfo models.BuildInformation,
-	args []string, os os.OS, osUser user.OSUser, unix unix.Unix,
-	cli cli.CLI) int {
+	args []string, logger logging.Logger, os os.OS, osUser user.OSUser, unix unix.Unix,
+	cli cli.CLI) error {
 	if len(args) > 1 { // cli operation
-		var err error
 		switch args[1] {
 		case "healthcheck":
-			err = cli.HealthCheck(background)
+			return cli.HealthCheck(background)
 		case "clientkey":
-			err = cli.ClientKey(args[2:], os.OpenFile)
+			return cli.ClientKey(args[2:], os.OpenFile)
 		case "openvpnconfig":
-			err = cli.OpenvpnConfig(os)
+			return cli.OpenvpnConfig(os)
 		case "update":
-			err = cli.Update(args[2:], os)
+			return cli.Update(args[2:], os)
 		default:
-			err = fmt.Errorf("command %q is unknown", args[1])
+			return fmt.Errorf("command %q is unknown", args[1])
 		}
-		if err != nil {
-			fmt.Println(err)
-			return 1
-		}
-		return 0
 	}
 	ctx, cancel := context.WithCancel(background)
 	defer cancel()
-	logger := createLogger()
 
 	const clientTimeout = 15 * time.Second
 	httpClient := &http.Client{Timeout: clientTimeout}
@@ -114,26 +151,22 @@ func _main(background context.Context, buildInfo models.BuildInformation,
 
 	allSettings, err := settings.GetAllSettings(paramsReader)
 	if err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 	logger.Info(allSettings.String())
 
 	if err := os.MkdirAll("/tmp/gluetun", 0644); err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 	if err := os.MkdirAll("/gluetun", 0644); err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 
 	// TODO run this in a loop or in openvpn to reload from file without restarting
 	storage := storage.New(logger, os, constants.ServersData)
 	allServers, err := storage.SyncServers(constants.GetAllServers())
 	if err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 
 	// Should never change
@@ -142,16 +175,14 @@ func _main(background context.Context, buildInfo models.BuildInformation,
 	const defaultUsername = "nonrootuser"
 	nonRootUsername, err := alpineConf.CreateUser(defaultUsername, puid)
 	if err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 	if nonRootUsername != defaultUsername {
 		logger.Info("using existing username %s corresponding to user id %d", nonRootUsername, puid)
 	}
 
 	if err := os.Chown("/etc/unbound", puid, pgid); err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 
 	if allSettings.Firewall.Debug {
@@ -161,27 +192,23 @@ func _main(background context.Context, buildInfo models.BuildInformation,
 
 	defaultInterface, defaultGateway, err := routingConf.DefaultRoute()
 	if err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 
 	localSubnet, err := routingConf.LocalSubnet()
 	if err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 
 	defaultIP, err := routingConf.DefaultIP()
 	if err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 
 	firewallConf.SetNetworkInformation(defaultInterface, defaultGateway, localSubnet, defaultIP)
 
 	if err := routingConf.Setup(); err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 	defer func() {
 		routingConf.SetVerbose(false)
@@ -191,20 +218,17 @@ func _main(background context.Context, buildInfo models.BuildInformation,
 	}()
 
 	if err := firewallConf.SetOutboundSubnets(ctx, allSettings.Firewall.OutboundSubnets); err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 	if err := routingConf.SetOutboundRoutes(allSettings.Firewall.OutboundSubnets); err != nil {
-		logger.Error(err)
-		return 1
+		return err
 	}
 
 	if err := ovpnConf.CheckTUN(); err != nil {
 		logger.Warn(err)
 		err = ovpnConf.CreateTUN()
 		if err != nil {
-			logger.Error(err)
-			return 1
+			return err
 		}
 	}
 
@@ -217,30 +241,27 @@ func _main(background context.Context, buildInfo models.BuildInformation,
 	if allSettings.Firewall.Enabled {
 		err := firewallConf.SetEnabled(ctx, true) // disabled by default
 		if err != nil {
-			logger.Error(err)
-			return 1
+			return err
 		}
 	}
 
 	for _, vpnPort := range allSettings.Firewall.VPNInputPorts {
 		err = firewallConf.SetAllowedPort(ctx, vpnPort, string(constants.TUN))
 		if err != nil {
-			logger.Error(err)
-			return 1
+			return err
 		}
 	}
 
 	for _, port := range allSettings.Firewall.InputPorts {
 		err = firewallConf.SetAllowedPort(ctx, port, defaultInterface)
 		if err != nil {
-			logger.Error(err)
-			return 1
+			return err
 		}
 	} // TODO move inside firewall?
 
 	wg := &sync.WaitGroup{}
 
-	go collectStreamLines(ctx, streamMerger, logger, signalTunnelReady)
+	go collectStreamLines(ctx, streamMerger, logger, signalTunnelReady) // TODO waitgroup
 
 	openvpnLooper := openvpn.NewLooper(allSettings.OpenVPN, nonRootUsername, puid, pgid, allServers,
 		ovpnConf, firewallConf, routingConf, logger, httpClient, os.OpenFile, streamMerger, cancel)
@@ -296,55 +317,18 @@ func _main(background context.Context, buildInfo models.BuildInformation,
 	// until openvpn is launched
 	_, _ = openvpnLooper.SetStatus(constants.Running) // TODO option to disable with variable
 
-	signalsCh := make(chan nativeos.Signal, 1)
-	signal.Notify(signalsCh,
-		syscall.SIGINT,
-		syscall.SIGTERM,
-		nativeos.Interrupt,
-	)
-	shutdownErrorsCount := 0
-	select {
-	case signal := <-signalsCh:
-		logger.Warn("Caught OS signal %s, shutting down", signal)
-		cancel()
-	case <-ctx.Done():
-		logger.Warn("context canceled, shutting down")
-	}
+	<-ctx.Done()
+
 	if allSettings.OpenVPN.Provider.PortForwarding.Enabled {
 		logger.Info("Clearing forwarded port status file %s", allSettings.OpenVPN.Provider.PortForwarding.Filepath)
 		if err := os.Remove(string(allSettings.OpenVPN.Provider.PortForwarding.Filepath)); err != nil {
 			logger.Error(err)
-			shutdownErrorsCount++
 		}
 	}
-	const shutdownGracePeriod = 5 * time.Second
-	waiting, waited := context.WithTimeout(context.Background(), shutdownGracePeriod)
-	go func() {
-		defer waited()
-		wg.Wait()
-	}()
-	<-waiting.Done()
-	if waiting.Err() == context.DeadlineExceeded {
-		if shutdownErrorsCount > 0 {
-			logger.Warn("Shutdown had %d errors", shutdownErrorsCount)
-		}
-		logger.Warn("Shutdown timed out")
-		return 1
-	}
-	if shutdownErrorsCount > 0 {
-		logger.Warn("Shutdown had %d errors")
-		return 1
-	}
-	logger.Info("Shutdown successful")
-	return 0
-}
 
-func createLogger() logging.Logger {
-	logger, err := logging.NewLogger(logging.ConsoleEncoding, logging.InfoLevel)
-	if err != nil {
-		panic(err)
-	}
-	return logger
+	wg.Wait()
+
+	return nil
 }
 
 func printVersions(ctx context.Context, logger logging.Logger,