cli logging parameters overwrite config options

Parameters passed by command line must overwrite the options configured
in the config file.

closes #82

daemon/log/log.go

@@ -46,6 +46,7 @@ const (
 var (
 	WithColors = true
 	Output     = os.Stdout
+	StdoutFile = "/dev/stdout"
 	DateFormat = "2006-01-02 15:04:05"
 	MinLevel   = INFO
 
@@ -115,8 +116,8 @@ func Raw(format string, args ...interface{}) {
 
 // SetLogLevel sets the log level
 func SetLogLevel(newLevel int) {
-	mutex.RLock()
-	defer mutex.RUnlock()
+	mutex.Lock()
+	defer mutex.Unlock()
 	MinLevel = newLevel
 }
 
@@ -142,21 +143,35 @@ func Log(level int, format string, args ...interface{}) {
 }
 
 func setDefaultLogOutput() {
+	mutex.Lock()
 	Output = os.Stdout
+	mutex.Unlock()
 }
 
-// OpenFile opens a file the print out the logs
+// OpenFile opens a file to print out the logs
 func OpenFile(logFile string) (err error) {
-	mutex.Lock()
-	defer mutex.Unlock()
+	if logFile == StdoutFile {
+		setDefaultLogOutput()
+		return
+	}
 
 	if Output, err = os.OpenFile(logFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644); err != nil {
+		Error("Error opening log: ", logFile, err)
+		//fallback to stdout
 		setDefaultLogOutput()
 	}
+	Important("Start writing logs to ", logFile)
 
 	return err
 }
 
+// Close closes the current output file descriptor
+func Close() {
+	if Output != os.Stdout {
+		Output.Close()
+	}
+}
+
 // Debug is the log level for debugging purposes
 func Debug(format string, args ...interface{}) {
 	Log(DEBUG, format, args...)

daemon/main.go

@@ -65,15 +65,19 @@ func init() {
 	flag.BoolVar(&noLiveReload, "no-live-reload", debug, "Disable rules live reloading.")
 
 	flag.StringVar(&logFile, "log-file", logFile, "Write logs to this file instead of the standard output.")
-	flag.BoolVar(&debug, "debug", debug, "Enable debug logs.")
-	flag.BoolVar(&warning, "warning", warning, "Enable warning logs.")
+	flag.BoolVar(&debug, "debug", debug, "Enable debug level logs.")
+	flag.BoolVar(&warning, "warning", warning, "Enable warning level logs.")
 	flag.BoolVar(&important, "important", important, "Enable important level logs.")
 	flag.BoolVar(&errorlog, "error", errorlog, "Enable error level logs.")
 
 	flag.StringVar(&cpuProfile, "cpu-profile", cpuProfile, "Write CPU profile to this file.")
 	flag.StringVar(&memProfile, "mem-profile", memProfile, "Write memory profile to this file.")
 }
 
+func overwriteLogging() bool {
+	return debug || warning || important || errorlog || logFile != ""
+}
+
 func setupLogging() {
 	golog.SetOutput(ioutil.Discard)
 	if debug {
@@ -89,6 +93,7 @@ func setupLogging() {
 	}
 
 	if logFile != "" {
+		log.Close()
 		if err := log.OpenFile(logFile); err != nil {
 			log.Error("Error opening user defined log: ", logFile, err)
 		}
@@ -325,6 +330,9 @@ func main() {
 	pktChan = queue.Packets()
 
 	uiClient = ui.NewClient(uiSocket, stats, rules)
+	if overwriteLogging() {
+		setupLogging()
+	}
 	// overwrite monitor method from configuration if the user has passed
 	// the option via command line.
 	if procmonMethod != "" {