Add log rotation

pkg/logutil/factory.go

@@ -11,6 +11,7 @@ import (
 
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
+	"gopkg.in/natefinch/lumberjack.v2"
 )
 
 type Logger struct {
@@ -37,9 +38,6 @@ func NewLogger(logPath string) *Logger {
 		zapLevel = zapcore.DebugLevel
 	}
 
-	zapCfg := zap.NewDevelopmentConfig()
-	zapCfg.Level.SetLevel(zapLevel)
-
 	consoleCfg := zapcore.EncoderConfig{
 		TimeKey:        "time",
 		LevelKey:       "level",
@@ -53,6 +51,13 @@ func NewLogger(logPath string) *Logger {
 		EncodeDuration: zapcore.StringDurationEncoder,
 	}
 	consoleEncoder := zapcore.NewConsoleEncoder(consoleCfg)
+	consoleEncoderCore := zapcore.NewCore(consoleEncoder, zapcore.AddSync(os.Stdout), zapLevel)
+
+	// Set up file logging with overwrite mode
+	logFile := zapcore.AddSync(&lumberjack.Logger{
+		Filename: logPath,
+	})
+	fmt.Println("Logging to", logPath)
 
 	fileCfg := zapcore.EncoderConfig{
 		TimeKey:        "time",
@@ -67,20 +72,10 @@ func NewLogger(logPath string) *Logger {
 		EncodeDuration: zapcore.StringDurationEncoder,
 	}
 	fileEncoder := zapcore.NewConsoleEncoder(fileCfg)
+	fileEncoderCore := zapcore.NewCore(fileEncoder, zapcore.AddSync(logFile), zapLevel)
 
-	// Set up file logging with overwrite mode
-	logFile, err := os.OpenFile(logPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
-	if err != nil {
-		panic("cannot open log file: " + err.Error())
-	}
-	fmt.Println("Logging to", logPath)
-
-	core := zapcore.NewTee(
-		zapcore.NewCore(consoleEncoder, zapcore.AddSync(os.Stdout), zapCfg.Level),
-		zapcore.NewCore(fileEncoder, zapcore.AddSync(logFile), zapCfg.Level),
-	)
-
-	logger := zap.New(core, zap.AddCaller(), zap.Development())
+	cores := zapcore.NewTee(consoleEncoderCore, fileEncoderCore)
+	logger := zap.New(cores, zap.AddCaller(), zap.Development())
 	defer logger.Sync() // flushes buffer, if any
 	sugar := logger.Sugar()