support compress (pingcap#38)

config.go

@@ -36,6 +36,9 @@ type FileLogConfig struct {
 	MaxDays int `toml:"max-days" json:"max-days"`
 	// Maximum number of old log files to retain.
 	MaxBackups int `toml:"max-backups" json:"max-backups"`
+	// Compress function for rotated files.
+	// Currently only `gzip` and empty are supported, empty means compression disabled.
+	Compress string `toml:"compress" json:"compress"`
 }
 
 // Config serializes log related config in toml/json.

log.go

@@ -141,13 +141,24 @@ func initFileLog(cfg *FileLogConfig) (*lumberjack.Logger, error) {
 		cfg.MaxSize = defaultLogMaxSize
 	}
 
+	compress := false
+	switch cfg.Compress {
+	case "":
+		compress = false
+	case "gzip":
+		compress = true
+	default:
+		return nil, fmt.Errorf("can't set compress to `%s`", cfg.Compress)
+	}
+
 	// use lumberjack to logrotate
 	return &lumberjack.Logger{
 		Filename:   logPath,
 		MaxSize:    cfg.MaxSize,
 		MaxBackups: cfg.MaxBackups,
 		MaxAge:     cfg.MaxDays,
 		LocalTime:  true,
+		Compress:   compress,
 	}, nil
 }