[misc] Support configurable max log size with var NB_LOG_MAX_SIZE_MB (#2592)

* Support configurable max log size with var NB_LOG_MAX_SIZE_MB

* add better logs

util/log.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"path/filepath"
 	"slices"
+	"strconv"
 
 	log "github.com/sirupsen/logrus"
 	"gopkg.in/natefinch/lumberjack.v2"
@@ -12,6 +13,8 @@ import (
 	"github.com/netbirdio/netbird/formatter"
 )
 
+const defaultLogSize = 5
+
 // InitLog parses and sets log-level input
 func InitLog(logLevel string, logPath string) error {
 	level, err := log.ParseLevel(logLevel)
@@ -19,13 +22,14 @@ func InitLog(logLevel string, logPath string) error {
 		log.Errorf("Failed parsing log-level %s: %s", logLevel, err)
 		return err
 	}
-	customOutputs := []string{"console", "syslog"};
+	customOutputs := []string{"console", "syslog"}
 
 	if logPath != "" && !slices.Contains(customOutputs, logPath) {
+		maxLogSize := getLogMaxSize()
 		lumberjackLogger := &lumberjack.Logger{
 			// Log file absolute path, os agnostic
 			Filename:   filepath.ToSlash(logPath),
-			MaxSize:    5, // MB
+			MaxSize:    maxLogSize, // MB
 			MaxBackups: 10,
 			MaxAge:     30, // days
 			Compress:   true,
@@ -46,3 +50,18 @@ func InitLog(logLevel string, logPath string) error {
 	log.SetLevel(level)
 	return nil
 }
+
+func getLogMaxSize() int {
+	if sizeVar, ok := os.LookupEnv("NB_LOG_MAX_SIZE_MB"); ok {
+		size, err := strconv.ParseInt(sizeVar, 10, 64)
+		if err != nil {
+			log.Errorf("Failed parsing log-size %s: %s. Should be just an integer", sizeVar, err)
+			return defaultLogSize
+		}
+
+		log.Infof("Setting log file max size to %d MB", size)
+
+		return int(size)
+	}
+	return defaultLogSize
+}