turn off debug rook logging by default

cmd/rook/rook.go

@@ -16,12 +16,12 @@ var (
 )
 
 const (
-	systemLogDir   = "/var/log/rook"
+	debugLogVar    = "ROOK_DEBUG_DIR"
+	logFileName    = "rook.log"
 	outputPadding  = 3
 	outputMinWidth = 10
 	outputTabWidth = 0
 	outputPadChar  = ' '
-	logFileName    = "rook.log"
 )
 
 var rootCmd = &cobra.Command{
@@ -31,17 +31,7 @@ var rootCmd = &cobra.Command{
 }
 
 func Main() {
-	// set up logging to a log file instead of stdout (only command output and errors should go to stdout/stderr)
-	if err := os.MkdirAll(systemLogDir, 0744); err != nil {
-		log.Fatalf("failed to create logging dir '%s': %+v", systemLogDir, err)
-	}
-	logFilePath := filepath.Join(systemLogDir, logFileName)
-	logFile, err := os.OpenFile(logFilePath, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
-	if err != nil {
-		log.Fatalf("failed to open log file '%s': %v", logFilePath, err)
-	}
-	defer logFile.Close()
-	log.SetOutput(logFile)
+	enableLogging()
 
 	addCommands()
 	if err := rootCmd.Execute(); err != nil {
@@ -67,3 +57,22 @@ func addCommands() {
 func NewTableWriter(buffer io.Writer) *tabwriter.Writer {
 	return tabwriter.NewWriter(buffer, outputMinWidth, outputTabWidth, outputPadding, outputPadChar, 0)
 }
+
+func enableLogging() {
+	debugDir := os.Getenv(debugLogVar)
+	if debugDir == "" {
+		return
+	}
+
+	// set up logging to a log file instead of stdout (only command output and errors should go to stdout/stderr)
+	if err := os.MkdirAll(debugDir, 0744); err != nil {
+		log.Fatalf("failed to create logging dir '%s': %+v", debugDir, err)
+	}
+	logFilePath := filepath.Join(debugDir, logFileName)
+	logFile, err := os.OpenFile(logFilePath, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
+	if err != nil {
+		log.Fatalf("failed to open log file '%s': %v", logFilePath, err)
+	}
+	defer logFile.Close()
+	log.SetOutput(logFile)
+}