logger: add a flag to use UTC time for logging

cmd/root.go

@@ -28,6 +28,8 @@ const (
 	logCompressKey           = "log_compress"
 	logVerboseFlag           = "log-verbose"
 	logVerboseKey            = "log_verbose"
+	logUTCTimeFlag           = "log-utc-time"
+	logUTCTimeKey            = "log_utc_time"
 	loadDataFromFlag         = "loaddata-from"
 	loadDataFromKey          = "loaddata_from"
 	loadDataModeFlag         = "loaddata-mode"
@@ -44,6 +46,7 @@ const (
 	defaultLogMaxAge         = 28
 	defaultLogCompress       = false
 	defaultLogVerbose        = true
+	defaultLogUTCTime        = false
 	defaultLoadDataFrom      = ""
 	defaultLoadDataMode      = 1
 	defaultLoadDataQuotaScan = 0
@@ -59,6 +62,7 @@ var (
 	logMaxAge         int
 	logCompress       bool
 	logVerbose        bool
+	logUTCTime        bool
 	loadDataFrom      string
 	loadDataMode      int
 	loadDataQuotaScan int
@@ -180,6 +184,14 @@ using SFTPGO_LOG_VERBOSE env var too.
 `)
 	viper.BindPFlag(logVerboseKey, cmd.Flags().Lookup(logVerboseFlag)) //nolint:errcheck
 
+	viper.SetDefault(logUTCTimeKey, defaultLogUTCTime)
+	viper.BindEnv(logUTCTimeKey, "SFTPGO_LOG_UTC_TIME") //nolint:errcheck
+	cmd.Flags().BoolVar(&logUTCTime, logUTCTimeFlag, viper.GetBool(logUTCTimeKey),
+		`Use UTC time for logging. This flag can be set
+using SFTPGO_LOG_UTC_TIME env var too.
+`)
+	viper.BindPFlag(logUTCTimeKey, cmd.Flags().Lookup(logUTCTimeFlag)) //nolint:errcheck
+
 	viper.SetDefault(loadDataFromKey, defaultLoadDataFrom)
 	viper.BindEnv(loadDataFromKey, "SFTPGO_LOADDATA_FROM") //nolint:errcheck
 	cmd.Flags().StringVar(&loadDataFrom, loadDataFromFlag, viper.GetString(loadDataFromKey),