Add --log_path commandline arg to control log file path

cmd/commons/args.go

@@ -37,6 +37,7 @@ func SetCommonFlags(command *cobra.Command) {
 
 	command.Flags().StringP("config", "c", "", "Set config file (yaml)")
 	command.Flags().String("instance_id", "", "Set instance ID")
+	command.Flags().String("log_path", "", "Set log file path")
 
 	command.Flags().String("host", "", "Set iRODS host")
 	command.Flags().Int("port", 1247, "Set iRODS port")
@@ -229,6 +230,14 @@ func ProcessCommonFlags(command *cobra.Command, args []string) (*commons.Config,
 		}
 	}
 
+	logPathFlag := command.Flags().Lookup("log_path")
+	if logPathFlag != nil {
+		logPath := logPathFlag.Value.String()
+		if len(logPath) > 0 {
+			config.LogPath = logPath
+		}
+	}
+
 	dataRootFlag := command.Flags().Lookup("data_root")
 	if dataRootFlag != nil {
 		dataRoot := dataRootFlag.Value.String()

cmd/commons/daemon.go

@@ -28,6 +28,10 @@ func (w *NilWriter) Write(p []byte) (n int, err error) {
 	return len(p), nil
 }
 
+func (w *NilWriter) Close() (err error) {
+	return nil
+}
+
 func ReportChildProcessError() {
 	fmt.Fprintln(os.Stderr, InterProcessCommunicationFinishError)
 }
@@ -182,14 +186,16 @@ func ChildProcessReadConfigViaSTDIN() (*commons.Config, io.WriteCloser, error) {
 	}
 
 	// output to log file
-	var logWriter io.WriteCloser
 	logFilePath := config.GetLogFilePath()
-	if len(logFilePath) > 0 {
+	if len(logFilePath) > 0 && logFilePath != "-" {
 		logWriter, childLogFilePath := getLogWriterForChildProcess(logFilePath)
 		log.SetOutput(logWriter)
 
 		logger.Infof("Logging to %s", childLogFilePath)
+		return config, logWriter, nil
+	} else {
+		var nilWriter NilWriter
+		log.SetOutput(&nilWriter)
+		return config, &nilWriter, nil
 	}
-
-	return config, logWriter, nil
 }

commons/config.go

@@ -240,6 +240,11 @@ func (config *Config) GetInstanceDataRootDirPath() string {
 // MakeLogDir makes a log dir required
 func (config *Config) MakeLogDir() error {
 	logFilePath := config.GetLogFilePath()
+	if logFilePath == "-" {
+		// skip
+		return nil
+	}
+
 	logDirPath := filepath.Dir(logFilePath)
 	err := config.makeDir(logDirPath)
 	if err != nil {