Save logs to file and rotate it

cmd/server/main.go

@@ -65,6 +65,8 @@ func handleSignals(sig os.Signal) (exitNow bool) {
 }
 
 func main() {
+	defer logger.Sync()
+
 	ctx, cancelFn := context.WithCancel(context.Background())
 	// os signal handler
 	shutdownCh := make(chan struct{})
@@ -92,6 +94,15 @@ func main() {
 		logger.Get().With(zap.Error(err)).Error("Failed to validate the config file")
 		return
 	}
+
+	if cfg.Log != nil && cfg.Log.Filename != "" {
+		logger.Get().Info("Logs will be saved to " + cfg.Log.Filename)
+		if err := logger.InitLoggerRotate(cfg.Log.Level, cfg.Log.Filename, cfg.Log.MaxBackups, cfg.Log.MaxAge, cfg.Log.MaxSize, cfg.Log.Compress); err != nil {
+			logger.Get().With(zap.Error(err)).Error("Failed to init the log rotate")
+			return
+		}
+	}
+
 	srv, err := server.NewServer(cfg)
 	if err != nil {
 		logger.Get().With(zap.Error(err)).Error("Failed to create the server")

config/config-consul.yaml

@@ -39,4 +39,13 @@ consul:
 controller:
   failover:
     ping_interval_seconds: 3
-    min_alive_size: 5
+    min_alive_size: 5
+
+# Uncomment this part to save logs to filename instead of stdout
+#log:
+#  level: info
+#  filename: /data/logs/kvctl.log
+#  max_backups: 10
+#  max_age: 7
+#  max_size: 100
+#  compress: false

config/config-raft.yaml

@@ -42,3 +42,12 @@ controller:
   failover:
     ping_interval_seconds: 3
     min_alive_size: 5
+
+# Uncomment this part to save logs to filename instead of stdout
+#log:
+#  level: info
+#  filename: /data/logs/kvctl.log
+#  max_backups: 10
+#  max_age: 7
+#  max_size: 100
+#  compress: false

config/config-zk.yaml

@@ -36,4 +36,13 @@ zookeeper:
 controller:
   failover:
     ping_interval_seconds: 3
-    min_alive_size: 5
+    min_alive_size: 5
+
+# Uncomment this part to save logs to filename instead of stdout
+#log:
+#  level: info
+#  filename: /data/logs/kvctl.log
+#  max_backups: 10
+#  max_age: 7
+#  max_size: 100
+#  compress: false

config/config.go

@@ -49,6 +49,15 @@ type ControllerConfig struct {
 	FailOver *FailOverConfig `yaml:"failover"`
 }
 
+type LogConfig struct {
+	Level      string `yaml:"level"`
+	Filename   string `yaml:"filename"`
+	MaxBackups int    `yaml:"max_backups"`
+	MaxAge     int    `yaml:"max_age"`
+	MaxSize    int    `yaml:"max_size"`
+	Compress   bool   `yaml:"compress"`
+}
+
 const defaultPort = 9379
 
 type Config struct {
@@ -60,6 +69,7 @@ type Config struct {
 	Consul      *consul.Config    `yaml:"consul"`
 	Admin       AdminConfig       `yaml:"admin"`
 	Controller  *ControllerConfig `yaml:"controller"`
+	Log         *LogConfig        `yaml:"log"`
 }
 
 func DefaultFailOverConfig() *FailOverConfig {

config/config.yaml

@@ -41,4 +41,13 @@ etcd:
 controller:
   failover:
     ping_interval_seconds: 3
-    min_alive_size: 5
+    min_alive_size: 5
+
+# Uncomment this part to save logs to filename instead of stdout
+#log:
+#  level: info
+#  filename: /data/logs/kvctl.log
+#  max_backups: 10
+#  max_age: 7
+#  max_size: 100
+#  compress: false

go.mod

@@ -22,9 +22,12 @@ require (
 	go.etcd.io/etcd/raft/v3 v3.5.18
 	go.etcd.io/etcd/server/v3 v3.5.18
 	go.uber.org/zap v1.27.0
+	gopkg.in/natefinch/lumberjack.v2 v2.0.0
 	gopkg.in/yaml.v1 v1.0.0-20140924161607-9f9df34309c0
 )
 
+require github.com/BurntSushi/toml v1.4.0 // indirect
+
 require (
 	github.com/armon/go-metrics v0.4.1 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect

go.sum

@@ -1,4 +1,6 @@
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+github.com/BurntSushi/toml v1.4.0 h1:kuoIxZQy2WRRk1pttg9asf+WVv6tWQuBNVmK8+nqPr0=
+github.com/BurntSushi/toml v1.4.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
 github.com/DataDog/datadog-go v3.2.0+incompatible/go.mod h1:LButxg5PwREeZtORoXG3tL4fMGNddJ+vMq1mwgfaqoQ=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
@@ -423,6 +425,8 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
+gopkg.in/natefinch/lumberjack.v2 v2.0.0 h1:1Lc07Kr7qY4U2YPouBjpCLxpiyxIVoxqXgkXLknAOE8=
+gopkg.in/natefinch/lumberjack.v2 v2.0.0/go.mod h1:l0ndWWf7gzL7RNwBG7wST/UCcT4T24xpD6X8LsfU/+k=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkepLTh2hOroT7a+7czfdQ=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v1 v1.0.0-20140924161607-9f9df34309c0 h1:POO/ycCATvegFmVuPpQzZFJ+pGZeX22Ufu6fibxDVjU=

logger/logger.go

@@ -20,8 +20,11 @@
 package logger
 
 import (
+	"fmt"
+
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
+	"gopkg.in/natefinch/lumberjack.v2"
 )
 
 var zapLogger *zap.Logger
@@ -36,3 +39,70 @@ func init() {
 	zapConfig.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
 	zapLogger, _ = zapConfig.Build()
 }
+
+func getEncoder() zapcore.Encoder {
+	encoderConfig := zap.NewProductionEncoderConfig()
+	encoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+	encoderConfig.EncodeLevel = zapcore.CapitalLevelEncoder
+	encoderConfig.TimeKey = "time"
+
+	return zapcore.NewJSONEncoder(encoderConfig)
+}
+
+func getWriteSyncer(filename string, maxBackups, maxAge, maxSize int, compress bool) (zapcore.WriteSyncer, error) {
+	lumberJackLogger := &lumberjack.Logger{
+		Filename:   filename,
+		MaxBackups: maxBackups,
+		MaxSize:    maxSize,
+		MaxAge:     maxAge,
+		Compress:   compress,
+	}
+
+	if _, err := lumberJackLogger.Write([]byte("test logfile writable\r\n")); err != nil {
+		return nil, fmt.Errorf("test writing to log file %s failed", filename)
+	}
+
+	return zapcore.AddSync(lumberJackLogger), nil
+}
+
+func InitLoggerRotate(level, filename string, maxBackups, maxAge, maxSize int, compress bool) error {
+	// if file path is empty, use default zapLogger, print in console
+	if len(filename) == 0 {
+		return nil
+	}
+	if level != "info" && level != "warn" && level != "error" {
+		return fmt.Errorf("log level must be one of info,warn,error")
+	}
+	if maxBackups > 100 || maxBackups < 10 {
+		return fmt.Errorf("log max_backups must be between 10 and 100")
+	}
+	if maxAge > 30 || maxAge < 1 {
+		return fmt.Errorf("log max_age must be between 1 and 30")
+	}
+	if maxSize > 500 || maxSize < 100 {
+		return fmt.Errorf("log max_size must be between 100 and 500")
+	}
+
+	var l = new(zapcore.Level)
+	if err := l.UnmarshalText([]byte(level)); err != nil {
+		return err
+	}
+	encoder := getEncoder()
+	writeSync, err := getWriteSyncer(filename, maxBackups, maxAge, maxSize, compress)
+	if err != nil {
+		return err
+	}
+	core := zapcore.NewCore(encoder, writeSync, l)
+	rotateLogger := zap.New(core, zap.AddCaller())
+	zapLogger = rotateLogger
+
+	return nil
+}
+
+func Sync() {
+	if zapLogger != nil {
+		if err := zapLogger.Sync(); err != nil {
+			return
+		}
+	}
+}