Setup proper logging

cmd/after-lock/after-lock.go

@@ -6,9 +6,9 @@ import (
 	"after-lock/xdg/keypressdetector"
 	"after-lock/xdg/lockscreen"
 	"after-lock/lockfile"
-	"fmt"
 	"os"
 	"runtime/debug"
+	"log"
 )
 
 const (
@@ -17,11 +17,16 @@ const (
 	keyboardDeviceNode = "/dev/input/by-id/usb-Dell_Dell_USB_Entry_Keyboard-event-kbd"
 	lockfilePath = "/tmp/after-lock.lock"
 	printStackTraces = false
+	logFilePath = "/home/superuser/Desktop/after-lock.log"
 )
 
 
 func main() {
 	defer handleErrors()
+	f := initLogging()
+	if f != nil {
+		defer f.Close()
+	}
 
 	lock := grabExclusiveProcessLock()
 	defer lock.Unlock()
@@ -36,11 +41,25 @@ func main() {
 	al.Start()
 }
 
+func initLogging() *os.File {
+	if len(logFilePath) == 0 {
+		return nil
+	}
+
+	f, err := os.OpenFile(logFilePath, os.O_RDWR | os.O_CREATE | os.O_APPEND, 0600)
+	if err != nil {
+		panic(err)
+	}
+
+	log.SetOutput(f)
+	return f
+}
+
 func handleErrors() {
 	if err := recover(); err != nil {
-		fmt.Printf("Crashed with unexpected error: %v!\n", err)
+		log.Printf("Crashed with unexpected error: %v!\n", err)
 		if printStackTraces {
-			fmt.Printf("Stack trace:\n\n")
+			log.Printf("Stack trace:\n\n")
 			debug.PrintStack()
 		}
 		os.Exit(1)