Add log rotation

go.mod

@@ -21,6 +21,7 @@ require (
 require (
 	github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
+	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect
 )
 
 require (

go.sum

@@ -48,6 +48,8 @@ golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
 golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1 h1:bBRl1b0OH9s/DuPhuXpNl+VtCaJXFZ5/uEFST95x9zc=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1/go.mod h1:YD8tP3GAjkrDg1eZH7EGmyESg/lsYskCTPBJVb9jqSc=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

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()