From a99f944f335b7e6a60c9c222dffb987aa8b797a3 Mon Sep 17 00:00:00 2001
From: Ash Keel <ash@nebula.cafe>
Date: Sun, 4 Dec 2022 00:36:13 +0100
Subject: [PATCH] fix: server config doesn't get half-changed in case of error

---
 http/server.go | 50 +++++++++++++++++++++++++++++---------------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/http/server.go b/http/server.go
index e73fd2b..6dcaab9 100644
--- a/http/server.go
+++ b/http/server.go
@@ -8,6 +8,8 @@ import (
 	"net/http"
 	"net/http/pprof"
 
+	"github.com/strimertul/strimertul/utils"
+
 	"git.sr.ht/~hamcha/containers"
 	jsoniter "github.com/json-iterator/go"
 	"github.com/strimertul/strimertul/database"
@@ -20,14 +22,14 @@ import (
 var json = jsoniter.ConfigFastest
 
 type Server struct {
-	Config          ServerConfig
+	Config          *containers.RWSync[ServerConfig]
 	db              *database.LocalDBClient
 	logger          *zap.Logger
 	server          *http.Server
 	frontend        fs.FS
 	hub             *kv.Hub
 	mux             *http.ServeMux
-	requestedRoutes map[string]http.Handler
+	requestedRoutes *containers.SyncMap[string, http.Handler]
 	cancelConfigSub database.CancelFunc
 }
 
@@ -36,17 +38,18 @@ func NewServer(db *database.LocalDBClient, logger *zap.Logger) (*Server, error)
 		logger:          logger,
 		db:              db,
 		server:          &http.Server{},
-		requestedRoutes: make(map[string]http.Handler),
+		requestedRoutes: containers.NewSyncMap[string, http.Handler](),
+		Config:          containers.NewRWSync(ServerConfig{}),
 	}
 
-	err := db.GetJSON(ServerConfigKey, &server.Config)
+	err := utils.LoadJSONToWrapped[ServerConfig](ServerConfigKey, server.Config)
 	if err != nil {
 		// Initialize with default config
-		server.Config = ServerConfig{
+		server.Config.Set(ServerConfig{
 			Bind:               "localhost:4337",
 			EnableStaticServer: false,
 			KVPassword:         "",
-		}
+		})
 		// Save
 		err = db.PutJSON(ServerConfigKey, server.Config)
 		if err != nil {
@@ -59,7 +62,7 @@ func NewServer(db *database.LocalDBClient, logger *zap.Logger) (*Server, error)
 
 	// Set password
 	server.hub.SetOptions(kv.HubOptions{
-		Password: server.Config.KVPassword,
+		Password: server.Config.Get().KVPassword,
 	})
 
 	return server, nil
@@ -100,10 +103,11 @@ func (s *Server) makeMux() *http.ServeMux {
 			kv.ServeWs(s.hub, w, r)
 		})
 	}
-	if s.Config.EnableStaticServer {
-		mux.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir(s.Config.Path))))
+	config := s.Config.Get()
+	if config.EnableStaticServer {
+		mux.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir(config.Path))))
 	}
-	for route, handler := range s.requestedRoutes {
+	for route, handler := range s.requestedRoutes.Copy() {
 		mux.Handle(route, handler)
 	}
 
@@ -111,12 +115,12 @@ func (s *Server) makeMux() *http.ServeMux {
 }
 
 func (s *Server) RegisterRoute(route string, handler http.Handler) {
-	s.requestedRoutes[route] = handler
+	s.requestedRoutes.SetKey(route, handler)
 	s.mux = s.makeMux()
 }
 
 func (s *Server) UnregisterRoute(route string) {
-	delete(s.requestedRoutes, route)
+	s.requestedRoutes.DeleteKey(route)
 	s.mux = s.makeMux()
 }
 
@@ -126,22 +130,25 @@ func (s *Server) Listen() error {
 	exit := make(chan error)
 	var err error
 	err, s.cancelConfigSub = s.db.SubscribeKey(ServerConfigKey, func(value string) {
-		oldBind := s.Config.Bind
-		oldPassword := s.Config.KVPassword
-		err := json.Unmarshal([]byte(value), &s.Config)
+		oldConfig := s.Config.Get()
+
+		var config ServerConfig
+		err := json.Unmarshal([]byte(value), &config)
 		if err != nil {
 			s.logger.Error("Failed to unmarshal config", zap.Error(err))
 			return
 		}
+
+		s.Config.Set(config)
 		s.mux = s.makeMux()
 		// Restart hub if password changed
-		if oldPassword != s.Config.KVPassword {
+		if oldConfig.KVPassword != config.KVPassword {
 			s.hub.SetOptions(kv.HubOptions{
-				Password: s.Config.KVPassword,
+				Password: config.KVPassword,
 			})
 		}
 		// Restart server if bind changed
-		if oldBind != s.Config.Bind {
+		if oldConfig.Bind != config.Bind {
 			restart.Set(true)
 			err = s.server.Shutdown(context.Background())
 			if err != nil {
@@ -155,13 +162,14 @@ func (s *Server) Listen() error {
 	}
 	go func() {
 		for {
-			s.logger.Info("Starting HTTP server", zap.String("bind", s.Config.Bind))
+			config := s.Config.Get()
+			s.logger.Info("Starting HTTP server", zap.String("bind", config.Bind))
 			s.mux = s.makeMux()
 			s.server = &http.Server{
 				Handler: s,
-				Addr:    s.Config.Bind,
+				Addr:    config.Bind,
 			}
-			s.logger.Info("HTTP server started", zap.String("bind", s.Config.Bind))
+			s.logger.Info("HTTP server started", zap.String("bind", config.Bind))
 			err := s.server.ListenAndServe()
 			s.logger.Debug("HTTP server died", zap.Error(err))
 			if err != nil && !errors.Is(err, http.ErrServerClosed) {