feat: tailscale integration (#847)

internal/bootstrap/router_bootstrap.go

@@ -1,14 +1,29 @@
 package bootstrap
 
 import (
+	"context"
+	"errors"
 	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"time"
 
 	"github.com/tinyauthapp/tinyauth/internal/controller"
 	"github.com/tinyauthapp/tinyauth/internal/middleware"
+	"github.com/tinyauthapp/tinyauth/internal/model"
 
 	"github.com/gin-gonic/gin"
 )
 
+type Listener int
+
+const (
+	ListenerHTTP Listener = iota
+	ListenerUnix
+	ListenerTailscale
+)
+
 func (app *BootstrapApp) setupRouter() error {
 	// we don't want gin debug mode
 	gin.SetMode(gin.ReleaseMode)
@@ -24,7 +39,7 @@ func (app *BootstrapApp) setupRouter() error {
 		}
 	}
 
-	contextMiddleware := middleware.NewContextMiddleware(app.log, app.runtime, app.services.authService, app.services.oauthBrokerService)
+	contextMiddleware := middleware.NewContextMiddleware(app.log, app.runtime, app.services.authService, app.services.oauthBrokerService, app.services.tailscaleService)
 	engine.Use(contextMiddleware.Middleware())
 
 	uiMiddleware, err := middleware.NewUIMiddleware()
@@ -53,3 +68,161 @@ func (app *BootstrapApp) setupRouter() error {
 	app.router = engine
 	return nil
 }
+
+func (app *BootstrapApp) runListeners() (chan error, error) {
+	// lec -> listener error channel
+	lec := make(chan error, len(app.listeners))
+
+	for _, listenerType := range app.listeners {
+		listenerFunc, err := app.listenerFromType(listenerType)
+
+		if err != nil {
+			return nil, fmt.Errorf("failed to get listener function: %w", err)
+		}
+
+		app.wg.Go(func() {
+			lec <- listenerFunc()
+		})
+	}
+
+	return lec, nil
+}
+
+// The way we calculate listeners is as follows:
+// If concurrent listeners are disabled, we pick the first available listener, so:
+// 1. If tailscale is enabled, we use tailscale
+// 2. If socket path is configured, we use unix socket
+// 3. Finally if none is configured we use http
+// If concurrent listeners are enabled, we add all available listeners in the following order
+func (app *BootstrapApp) calculateListenerPolicy() []Listener {
+	l := []Listener{}
+
+	if !app.config.Server.ConcurrentListenersEnabled {
+		if app.config.Tailscale.Enabled {
+			l = append(l, ListenerTailscale)
+			return l
+		}
+
+		if app.config.Server.SocketPath != "" {
+			l = append(l, ListenerUnix)
+			return l
+		}
+
+		l = append(l, ListenerHTTP)
+		return l
+	}
+
+	if app.config.Server.SocketPath != "" {
+		l = append(l, ListenerUnix)
+	}
+
+	if app.config.Tailscale.Enabled {
+		l = append(l, ListenerTailscale)
+	}
+
+	l = append(l, ListenerHTTP)
+
+	return l
+}
+
+func (app *BootstrapApp) listenerFromType(listenerType Listener) (func() error, error) {
+	switch listenerType {
+	case ListenerHTTP:
+		return app.serveHTTP, nil
+	case ListenerUnix:
+		return app.serveUnix, nil
+	case ListenerTailscale:
+		return app.serveTailscale, nil
+	default:
+		return nil, fmt.Errorf("invalid listener type: %d", listenerType)
+	}
+}
+
+func (app *BootstrapApp) serveHTTP() error {
+	address := fmt.Sprintf("%s:%d", app.config.Server.Address, app.config.Server.Port)
+
+	app.log.App.Info().Msgf("Starting server on %s", address)
+
+	listener, err := net.Listen("tcp", address)
+
+	if err != nil {
+		return fmt.Errorf("failed to create tcp listener: %w", err)
+	}
+
+	server := &http.Server{
+		Addr:    address,
+		Handler: app.router.Handler(),
+	}
+
+	return app.serve(listener, server, "http")
+}
+
+func (app *BootstrapApp) serveUnix() error {
+	_, err := os.Stat(app.config.Server.SocketPath)
+
+	if err == nil {
+		app.log.App.Info().Msgf("Removing existing socket file %s", app.config.Server.SocketPath)
+		err := os.Remove(app.config.Server.SocketPath)
+
+		if err != nil {
+			return fmt.Errorf("failed to remove existing socket file: %w", err)
+		}
+	}
+
+	app.log.App.Info().Msgf("Starting server on unix socket %s", app.config.Server.SocketPath)
+
+	listener, err := net.Listen("unix", app.config.Server.SocketPath)
+
+	if err != nil {
+		return fmt.Errorf("failed to create unix socket listener: %w", err)
+	}
+
+	server := &http.Server{
+		Handler: app.router.Handler(),
+	}
+
+	return app.serve(listener, server, "unix socket")
+}
+
+func (app *BootstrapApp) serveTailscale() error {
+	app.log.App.Info().Msgf("Starting Tailscale server on %s", fmt.Sprintf("https://%s", app.services.tailscaleService.GetHostname()))
+
+	listener, err := app.services.tailscaleService.CreateListener()
+
+	if err != nil {
+		return fmt.Errorf("failed to create tailscale listener: %w", err)
+	}
+
+	server := &http.Server{
+		Handler: app.router.Handler(),
+	}
+
+	return app.serve(listener, server, "tailscale")
+}
+
+func (app *BootstrapApp) serve(listener net.Listener, server *http.Server, name string) error {
+	shutdown := func() {
+		ctx, cancel := context.WithTimeout(context.Background(), model.GracefulShutdownTimeout*time.Second)
+		defer cancel()
+		err := server.Shutdown(ctx)
+		if err != nil {
+			app.log.App.Error().Err(err).Msgf("Failed to shutdown %s listener gracefully", name)
+		}
+		listener.Close()
+	}
+
+	go func() {
+		<-app.ctx.Done()
+		app.log.App.Debug().Msgf("Shutting down %s listener", name)
+		shutdown()
+	}()
+
+	err := server.Serve(listener)
+
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
+		shutdown()
+		return fmt.Errorf("failed to start %s listener: %w", name, err)
+	}
+
+	return nil
+}