Simplified loop mechanism for openvpn and dns

- Refers to #91
- http control server starts without waiting for unbound and/or openvpn
- Trying to get rid of waiter and use channels directly
- Simpler main.go
- More robust logic overall

cmd/gluetun/main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"net"
 	"os"
 	"os/signal"
 	"regexp"
@@ -211,40 +210,49 @@ func _main(background context.Context, args []string) int {
 		go streamMerger.Merge(ctx, stderr, command.MergeName("shadowsocks error"), command.MergeColor(constants.ColorShadowsocksError()))
 	}
 
-	httpServer := server.New("0.0.0.0:8000", logger)
+	restartOpenvpn := make(chan struct{})
+	restartUnbound := make(chan struct{})
+	openvpnDone := make(chan struct{})
+	unboundDone := make(chan struct{})
+	serverDone := make(chan struct{})
 
-	go openvpnRunLoop(ctx, ovpnConf, streamMerger, logger, httpServer, waiter, fatalOnError)
+	openvpnLooper := openvpn.NewLooper(ovpnConf, allSettings.OpenVPN, logger, streamMerger, fatalOnError)
+	// wait for restartOpenvpn
+	go openvpnLooper.Run(ctx, restartOpenvpn, openvpnDone)
 
-	waiter.Add(func() error {
-		err := httpServer.Run(ctx)
-		logger.Error("http server: %s", err)
-		return err
-	})
-
-	startUnboundCh := make(chan struct{})
-	go unboundRunLoop(ctx, startUnboundCh, logger, dnsConf, allSettings.DNS, allSettings.System.UID, allSettings.System.GID, waiter, streamMerger, httpServer)
-	if !allSettings.DNS.Enabled {
-		httpServer.SetUnboundRestart(func() {})
-		dnsConf.UseDNSInternally(allSettings.DNS.PlaintextAddress)
-		if err := dnsConf.UseDNSSystemWide(allSettings.DNS.PlaintextAddress); err != nil {
-			logger.Error(err)
-		}
-	}
+	unboundLooper := dns.NewLooper(dnsConf, allSettings.DNS, logger,
+		streamMerger, allSettings.System.UID, allSettings.System.GID)
+	// wait for restartUnbound
+	go unboundLooper.Run(ctx, restartUnbound, unboundDone)
 
 	go func() {
+		first := true
+		var restartTickerContext context.Context
+		var restartTickerCancel context.CancelFunc = func() {}
 		for {
 			select {
 			case <-ctx.Done():
+				restartTickerCancel()
 				return
 			case <-connectedCh: // blocks until openvpn is connected
-				if allSettings.DNS.Enabled {
-					startUnboundCh <- struct{}{}
+				if first {
+					first = false
+					restartUnbound <- struct{}{}
 				}
+				restartTickerCancel()
+				restartTickerContext, restartTickerCancel = context.WithCancel(ctx)
+				go unboundLooper.RunRestartTicker(restartTickerContext, restartUnbound)
 				onConnected(allSettings, logger, fileManager, routingConf, defaultInterface, providerConf)
 			}
 		}
 	}()
 
+	httpServer := server.New("0.0.0.0:8000", logger, restartOpenvpn, restartUnbound)
+	go httpServer.Run(ctx, serverDone)
+
+	// Start openvpn for the first time
+	restartOpenvpn <- struct{}{}
+
 	signalsCh := make(chan os.Signal, 1)
 	signal.Notify(signalsCh,
 		syscall.SIGINT,
@@ -278,6 +286,9 @@ func _main(background context.Context, args []string) int {
 		logger.Error(err)
 		exitStatus = 1
 	}
+	<-serverDone
+	<-unboundDone
+	<-openvpnDone
 	return exitStatus
 }
 
@@ -348,34 +359,6 @@ func trimEventualProgramPrefix(s string) string {
 	}
 }
 
-func openvpnRunLoop(ctx context.Context, ovpnConf openvpn.Configurator, streamMerger command.StreamMerger,
-	logger logging.Logger, httpServer server.Server, waiter command.Waiter, fatalOnError func(err error)) {
-	logger = logger.WithPrefix("openvpn: ")
-	waitErrors := make(chan error)
-	for ctx.Err() == nil {
-		logger.Info("starting")
-		openvpnCtx, openvpnCancel := context.WithCancel(ctx)
-		stream, waitFn, err := ovpnConf.Start(openvpnCtx)
-		fatalOnError(err)
-		httpServer.SetOpenVPNRestart(openvpnCancel)
-		go streamMerger.Merge(openvpnCtx, stream, command.MergeName("openvpn"), command.MergeColor(constants.ColorOpenvpn()))
-		waiter.Add(func() error {
-			return <-waitErrors
-		})
-		err = waitFn()
-		waitErrors <- fmt.Errorf("openvpn: %w", err)
-		switch {
-		case ctx.Err() != nil:
-			logger.Warn("context canceled: exiting openvpn run loop")
-		case openvpnCtx.Err() == context.Canceled:
-			logger.Info("triggered openvpn restart")
-		default:
-			logger.Warn(err)
-			openvpnCancel()
-		}
-	}
-}
-
 func onConnected(allSettings settings.Settings,
 	logger logging.Logger, fileManager files.FileManager,
 	routingConf routing.Routing, defaultInterface string,
@@ -393,7 +376,7 @@ func onConnected(allSettings settings.Settings,
 	} else {
 		logger.Info("Gateway VPN IP address: %s", vpnGatewayIP)
 	}
-	time.AfterFunc(7*time.Second, func() { // wait for Unbound to start - TODO use signal channel
+	time.AfterFunc(10*time.Second, func() { // wait for Unbound to start - TODO use signal channel
 		publicIP, err := publicip.NewIPGetter(network.NewClient(3 * time.Second)).Get()
 		if err != nil {
 			logger.Error(err)
@@ -411,126 +394,6 @@ func onConnected(allSettings settings.Settings,
 	})
 }
 
-func fallbackToUnencryptedIPv4DNS(dnsConf dns.Configurator, providers []models.DNSProvider) error {
-	var targetIP net.IP
-	for _, provider := range providers {
-		data := constants.DNSProviderMapping()[provider]
-		for _, targetIP = range data.IPs {
-			if targetIP.To4() != nil {
-				dnsConf.UseDNSInternally(targetIP)
-				return dnsConf.UseDNSSystemWide(targetIP)
-			}
-		}
-	}
-	// No IPv4 address found
-	return fmt.Errorf("no ipv4 DNS address found for providers %s", providers)
-}
-
-func unboundRun(ctx, oldCtx context.Context, oldCancel context.CancelFunc, timer *time.Timer,
-	dnsConf dns.Configurator, settings settings.DNS, uid, gid int,
-	streamMerger command.StreamMerger, waiter command.Waiter, httpServer server.Server) (
-	newCtx context.Context, newCancel context.CancelFunc, setupErr, startErr, waitErr error) {
-	if timer != nil {
-		timer.Stop()
-		timer.Reset(settings.UpdatePeriod)
-	}
-	if err := dnsConf.DownloadRootHints(uid, gid); err != nil {
-		return oldCtx, oldCancel, err, nil, nil
-	}
-	if err := dnsConf.DownloadRootKey(uid, gid); err != nil {
-		return oldCtx, oldCancel, err, nil, nil
-	}
-	if err := dnsConf.MakeUnboundConf(settings, uid, gid); err != nil {
-		return oldCtx, oldCancel, err, nil, nil
-	}
-	newCtx, newCancel = context.WithCancel(ctx)
-	oldCancel()
-	stream, waitFn, err := dnsConf.Start(newCtx, settings.VerbosityDetailsLevel)
-	if err != nil {
-		return newCtx, newCancel, nil, err, nil
-	}
-	go streamMerger.Merge(newCtx, stream, command.MergeName("unbound"), command.MergeColor(constants.ColorUnbound()))
-	dnsConf.UseDNSInternally(net.IP{127, 0, 0, 1})                         // use Unbound
-	if err := dnsConf.UseDNSSystemWide(net.IP{127, 0, 0, 1}); err != nil { // use Unbound
-		return newCtx, newCancel, nil, err, nil
-	}
-	if err := dnsConf.WaitForUnbound(); err != nil {
-		return newCtx, newCancel, nil, err, nil
-	}
-	// Unbound is up and running at this point
-	httpServer.SetUnboundRestart(newCancel)
-	waitError := make(chan error)
-	waiterError := make(chan error)
-	waiter.Add(func() error { //nolint:scopelint
-		return <-waiterError
-	})
-	go func() {
-		err := fmt.Errorf("unbound: %w", waitFn())
-		waitError <- err
-		waiterError <- err
-	}()
-	if timer == nil {
-		waitErr := <-waitError
-		return newCtx, newCancel, nil, nil, waitErr
-	}
-	select {
-	case <-timer.C:
-		return newCtx, newCancel, nil, nil, nil
-	case waitErr := <-waitError:
-		return newCtx, newCancel, nil, nil, waitErr
-	}
-}
-
-func unboundRunLoop(ctx context.Context, startCh chan struct{}, logger logging.Logger, dnsConf dns.Configurator,
-	settings settings.DNS, uid, gid int,
-	waiter command.Waiter, streamMerger command.StreamMerger, httpServer server.Server,
-) {
-	logger = logger.WithPrefix("unbound dns over tls setup: ")
-	select {
-	case <-startCh:
-	case <-ctx.Done():
-		logger.Warn("context canceled: exiting unbound run loop")
-		return
-	}
-	if err := fallbackToUnencryptedIPv4DNS(dnsConf, settings.Providers); err != nil {
-		logger.Error(err)
-	}
-	var timer *time.Timer
-	if settings.UpdatePeriod > 0 {
-		timer = time.NewTimer(settings.UpdatePeriod)
-	}
-	unboundCtx, unboundCancel := context.WithCancel(ctx)
-	defer unboundCancel()
-	for ctx.Err() == nil {
-		var setupErr, startErr, waitErr error
-		unboundCtx, unboundCancel, setupErr, startErr, waitErr = unboundRun(
-			ctx, unboundCtx, unboundCancel, timer, dnsConf, settings,
-			uid, gid, streamMerger, waiter, httpServer)
-		switch {
-		case ctx.Err() != nil:
-			logger.Warn("context canceled: exiting unbound run loop")
-		case timer != nil && !timer.Stop():
-			logger.Info("planned restart of unbound")
-		case unboundCtx.Err() == context.Canceled:
-			logger.Info("triggered restart of unbound")
-		case setupErr != nil:
-			logger.Warn(setupErr)
-		case startErr != nil:
-			logger.Error(startErr)
-			unboundCancel()
-			if err := fallbackToUnencryptedIPv4DNS(dnsConf, settings.Providers); err != nil {
-				logger.Error(err)
-			}
-		case waitErr != nil:
-			logger.Warn(waitErr)
-			if err := fallbackToUnencryptedIPv4DNS(dnsConf, settings.Providers); err != nil {
-				logger.Error(err)
-			}
-			logger.Warn("restarting unbound because of unexpected exit")
-		}
-	}
-}
-
 func setupPortForwarding(logger logging.Logger, providerConf provider.Provider, filepath models.Filepath, uid, gid int) {
 	pfLogger := logger.WithPrefix("port forwarding: ")
 	var port uint16