config watcher, restart server on change

go.mod

@@ -12,6 +12,7 @@ require (
 require (
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/kr/pretty v0.3.1 // indirect
+	golang.org/x/sys v0.22.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 )
 
@@ -31,4 +32,5 @@ require (
 	golang.org/x/sync v0.7.0 // indirect
 	golang.org/x/text v0.16.0 // indirect
 	golang.org/x/time v0.5.0
+	gopkg.in/fsnotify.v1 v1.4.7
 )

go.sum

@@ -21,6 +21,7 @@ github.com/decred/dcrd/crypto/blake256 v1.0.0 h1:/8DMNYp9SGi5f0w7uCm6d6M4OU2rGFK
 github.com/decred/dcrd/crypto/blake256 v1.0.0/go.mod h1:sQl2p6Y26YV+ZOcSTP6thNdn47hh8kt6rqSlvmrXFAc=
 github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1 h1:YLtO71vCjJRCBcrPMtQ9nqBsqpA1m5sE92cU+pd5Mcc=
 github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1/go.mod h1:hyedUtir6IdtD/7lIxGeCxkaw7y45JueMRL4DIyJDKs=
+github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/snappy v0.0.4 h1:yAGX7huGHXlcLOEtBnF4w7FQwA26wojNCwOYAEhLjQM=
@@ -82,6 +83,8 @@ golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
+golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -99,6 +102,7 @@ golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8T
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/fsnotify.v1 v1.4.7 h1:xOHLXZwVvI9hhs+cLKq5+I5onOuwQLhQwiu63xxlHs4=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

main.go

@@ -11,6 +11,10 @@ import (
 	"grain/server/utils"
 	"log"
 	"net/http"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
 	"time"
 
 	"golang.org/x/net/websocket"
@@ -20,6 +24,15 @@ func main() {
 	utils.EnsureFileExists("config.yml", "app/static/examples/config.example.yml")
 	utils.EnsureFileExists("relay_metadata.json", "app/static/examples/relay_metadata.example.json")
 
+	restartChan := make(chan struct{})
+	go utils.WatchConfigFile("config.yml", restartChan)
+
+	signalChan := make(chan os.Signal, 1)
+	signal.Notify(signalChan, syscall.SIGINT, syscall.SIGTERM)
+
+	var wg sync.WaitGroup
+	for {
+		wg.Add(1)
 		cfg, err := config.LoadConfig("config.yml")
 		if err != nil {
 			log.Fatal("Error loading config: ", err)
@@ -29,7 +42,6 @@ func main() {
 		if err != nil {
 			log.Fatal("Error initializing database: ", err)
 		}
-	defer db.DisconnectDB(client)
 
 		config.SetupRateLimiter(cfg)
 		config.SetupSizeLimiter(cfg)
@@ -40,8 +52,23 @@ func main() {
 		}
 
 		mux := setupRoutes()
+		server := startServer(cfg, mux, &wg)
 
-	startServer(cfg, mux)
+		select {
+		case <-restartChan:
+			log.Println("Restarting server...")
+			server.Close()
+			db.DisconnectDB(client)
+			wg.Wait()              // Wait for the server to fully shut down before restarting
+			time.Sleep(3 * time.Second) // Add a delay before restarting
+		case <-signalChan:
+			log.Println("Shutting down server...")
+			server.Close()
+			db.DisconnectDB(client)
+			wg.Wait() // Wait for the server to fully shut down before exiting
+			return
+		}
+	}
 }
 
 func setupRoutes() *http.ServeMux {
@@ -56,7 +83,7 @@ func setupRoutes() *http.ServeMux {
 	return mux
 }
 
-func startServer(config *configTypes.ServerConfig, mux *http.ServeMux) {
+func startServer(config *configTypes.ServerConfig, mux *http.ServeMux, wg *sync.WaitGroup) *http.Server {
 	server := &http.Server{
 		Addr:         config.Server.Port,
 		Handler:      mux,
@@ -64,11 +91,16 @@ func startServer(config *configTypes.ServerConfig, mux *http.ServeMux) {
 		WriteTimeout: time.Duration(config.Server.WriteTimeout) * time.Second,
 		IdleTimeout:  time.Duration(config.Server.IdleTimeout) * time.Second,
 	}
+
+	go func() {
+		defer wg.Done() // Notify that the server is done shutting down
 		fmt.Printf("Server is running on http://localhost%s\n", config.Server.Port)
 		err := server.ListenAndServe()
-	if err != nil {
+		if err != nil && err != http.ErrServerClosed {
 			fmt.Println("Error starting server:", err)
 		}
+	}()
+	return server
 }
 
 var wsServer = &websocket.Server{

server/utils/watchConfig.go

@@ -0,0 +1,52 @@
+package utils
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	"gopkg.in/fsnotify.v1"
+)
+
+func WatchConfigFile(filePath string, restartChan chan<- struct{}) {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		log.Fatal("Error creating file watcher:", err)
+	}
+	defer watcher.Close()
+
+	err = watcher.Add(filePath)
+	if err != nil {
+		log.Fatal("Error adding file to watcher:", err)
+	}
+
+	var debounceTimer *time.Timer
+	debounceDuration := 1 * time.Second // Adjust this duration as needed
+
+	for {
+		select {
+		case event, ok := <-watcher.Events:
+			if !ok {
+				return
+			}
+			if event.Op&fsnotify.Write == fsnotify.Write {
+				if debounceTimer != nil {
+					debounceTimer.Stop() // Cancel the previous timer
+				}
+				debounceTimer = time.AfterFunc(debounceDuration, func() {
+					fmt.Println("Config file modified, restarting server...")
+					select {
+					case restartChan <- struct{}{}:
+					default:
+						// Skip sending restart signal if there's already one in the channel
+					}
+				})
+			}
+		case err, ok := <-watcher.Errors:
+			if !ok {
+				return
+			}
+			log.Println("Error watching file:", err)
+		}
+	}
+}