Log debug entries to file

.gitignore

@@ -1,3 +1,4 @@
 lanchat
 .vscode
 bin/
+*.log

lan/scan.go

@@ -112,12 +112,12 @@ func (s *DefaultScanner) scanHost(ips []string, chatPort int) (string, bool) {
 
 	hostInCh := make(chan string)
 	logger.Debugf("Scanning %d hosts\n", len(ips))
-	go func(ch chan string) {
+	go func() {
 		for _, host := range ips {
 			hostInCh <- host
 		}
-		close(ch)
-	}(hostInCh)
+		close(hostInCh)
+	}()
 
 	ctx, cancel := context.WithCancel(context.Background())
 	resCh := make(chan string)
@@ -145,7 +145,8 @@ func (s *DefaultScanner) scanHost(ips []string, chatPort int) (string, bool) {
 
 var wg sync.WaitGroup
 
-const numWorkers = 15
+const numWorkers = 10
+const timeout = 100 * time.Millisecond
 
 func popScan(ctx context.Context, chatPort int, in chan string, out chan string) {
 	for {
@@ -159,11 +160,12 @@ func popScan(ctx context.Context, chatPort int, in chan string, out chan string)
 				return
 			}
 			url := fmt.Sprintf("%s:%d", host, chatPort)
-			logger.Debugf("scanning %s\n", url)
-			conn, err := net.DialTimeout("tcp", url, 100*time.Millisecond)
+			logger.Debugf("scanning %s", url)
+			conn, err := net.DialTimeout("tcp", url, timeout)
 			if err == nil {
 				conn.Close()
 				out <- url
+				wg.Done()
 				return
 			}
 		}

logger/logger.go

@@ -14,13 +14,13 @@ var (
 )
 
 const (
-	logLevelErr = iota
-	logLevelWarn
-	logLevelInfo
-	logLevelDebug
+	LogLevelErr = iota
+	LogLevelWarn
+	LogLevelInfo
+	LogLevelDebug
 )
 
-const LogLevel = logLevelInfo
+const LogLevel = LogLevelInfo
 
 func init() {
 	out := os.Stdout
@@ -31,56 +31,59 @@ func init() {
 }
 
 func Init(w io.Writer) {
-	debugLogger = log.New(w, "[D]", log.Ldate|log.Ltime|log.Lshortfile)
-	infoLogger = log.New(w, "[I]", log.Ldate|log.Ltime)
-	warnLogger = log.New(w, "[W]", log.Ldate|log.Ltime)
-	errLogger = log.New(w, "[E]", log.Ldate|log.Ltime)
+	infoLogger.SetOutput(w)
+	warnLogger.SetOutput(w)
+	errLogger.SetOutput(w)
+}
+
+func InitDebug(w io.Writer) {
+	debugLogger.SetOutput(w)
 }
 
 func Debug(msg string) {
-	if LogLevel >= logLevelDebug {
+	if LogLevel >= LogLevelDebug {
 		debugLogger.Print(msg)
 	}
 }
 
 func Debugf(format string, v ...interface{}) {
-	if LogLevel >= logLevelDebug {
+	if LogLevel >= LogLevelDebug {
 		debugLogger.Printf(format, v...)
 	}
 }
 
 func Info(msg string) {
-	if LogLevel >= logLevelInfo {
+	if LogLevel >= LogLevelInfo {
 		infoLogger.Print(msg)
 	}
 }
 
 func Infof(format string, v ...interface{}) {
-	if LogLevel >= logLevelInfo {
+	if LogLevel >= LogLevelInfo {
 		infoLogger.Printf(format, v...)
 	}
 }
 
 func Warn(msg string) {
-	if LogLevel >= logLevelWarn {
+	if LogLevel >= LogLevelWarn {
 		warnLogger.Print(msg)
 	}
 }
 
 func Warnf(format string, v ...interface{}) {
-	if LogLevel >= logLevelWarn {
+	if LogLevel >= LogLevelWarn {
 		warnLogger.Printf(format, v...)
 	}
 }
 
 func Error(msg string) {
-	if LogLevel >= logLevelErr {
+	if LogLevel >= LogLevelErr {
 		errLogger.Print(msg)
 	}
 }
 
 func Errorf(format string, v ...interface{}) {
-	if LogLevel >= logLevelErr {
+	if LogLevel >= LogLevelErr {
 		errLogger.Printf(format, v...)
 	}
 }

main.go

@@ -3,6 +3,8 @@ package main
 import (
 	"context"
 	"fmt"
+	"log"
+	"os"
 
 	"github.com/MarcPer/lanchat/lan"
 	"github.com/MarcPer/lanchat/logger"
@@ -25,6 +27,9 @@ func main() {
 	logger.Infof("Starting UI\n")
 	renderer := ui.New(cfg.username, toUI, fromUI)
 	logger.Init(&renderer)
+	f := debugFile()
+	defer f.Close()
+	logger.InitDebug(f)
 
 	client := &lan.Client{Name: cfg.username, HostPort: cfg.port, FromUI: fromUI, ToUI: toUI, Scanner: scanner}
 	ctx, cancel := context.WithCancel(context.Background())
@@ -34,3 +39,18 @@ func main() {
 	cancel()
 	fmt.Println("bye")
 }
+
+func debugFile() *os.File {
+	var debugPath string
+	if logger.LogLevel >= logger.LogLevelDebug {
+		debugPath = "debug.log"
+	} else {
+		debugPath = os.DevNull
+	}
+
+	f, err := os.OpenFile(debugPath, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+	return f
+}