fix: accept log levels supported by older zot versions, validate configured log level

pkg/cli/server/root.go

@@ -1068,6 +1068,13 @@ func LoadConfiguration(config *config.Config, configPath string) error {
 		return err
 	}
 
+	// Validate log level before creating logger to avoid panic
+	if _, err := zlog.ParseLevel(config.Log.Level); err != nil {
+		logger.Error().Err(zerr.ErrBadConfig).Str("level", config.Log.Level).Msg(err.Error())
+
+		return err
+	}
+
 	log := zlog.NewLogger(config.Log.Level, config.Log.Output)
 
 	if len(metaData.Keys) == 0 {

pkg/cli/server/root_test.go

@@ -201,6 +201,30 @@ storage:
 		So(err, ShouldBeNil)
 	})
 
+	Convey("Test verify config with invalid log level", t, func(c C) {
+		content := `{"distSpecVersion":"1.1.1","storage":{"rootDirectory":"/tmp/zot"},
+							"http":{"address":"127.0.0.1","port":"8080","realm":"zot"},
+							"log":{"level":"invalid"}}`
+		tmpfile := MakeTempFileWithContent(t, "zot-test.json", content)
+
+		os.Args = []string{"cli_test", "verify", tmpfile}
+		err := cli.NewServerRootCmd().Execute()
+		So(err, ShouldNotBeNil)
+		So(err.Error(), ShouldContainSubstring, "invalid log level")
+		So(err.Error(), ShouldContainSubstring, "invalid")
+	})
+
+	Convey("Test verify config with valid trace log level", t, func(c C) {
+		content := `{"distSpecVersion":"1.1.1","storage":{"rootDirectory":"/tmp/zot"},
+							"http":{"address":"127.0.0.1","port":"8080","realm":"zot"},
+							"log":{"level":"trace"}}`
+		tmpfile := MakeTempFileWithContent(t, "zot-test.json", content)
+
+		os.Args = []string{"cli_test", "verify", tmpfile}
+		err := cli.NewServerRootCmd().Execute()
+		So(err, ShouldBeNil)
+	})
+
 	Convey("Test verify CVE warn for remote storage", t, func(c C) {
 		content := `{
 			"storage":{

pkg/log/log.go

@@ -258,19 +258,22 @@ func (e *Event) Msg(msg string) {
 	}
 }
 
-// parseLevel converts string level to slog.Level.
-func parseLevel(level string) (slog.Level, error) {
+// ParseLevel converts string level to slog.Level.
+func ParseLevel(level string) (slog.Level, error) {
+	const supportedLevels = "debug, trace, info, warn, warning, error, fatal, panic"
+
 	switch strings.ToLower(level) {
-	case "debug":
+	case "debug", "trace":
 		return slog.LevelDebug, nil
 	case "info":
 		return slog.LevelInfo, nil
 	case "warn", "warning":
 		return slog.LevelWarn, nil
-	case "error":
+	case "error", "fatal", "panic":
 		return slog.LevelError, nil
 	default:
-		return slog.LevelInfo, errors.ErrBadConfig
+		return slog.LevelInfo, fmt.Errorf("%w: invalid log level '%s', supported levels are: %s",
+			errors.ErrBadConfig, level, supportedLevels)
 	}
 }
 
@@ -292,7 +295,7 @@ func NewLogger(level, output string) Logger {
 
 func NewAuditLogger(level, output string) *Logger {
 	// Parse log level
-	lvl, err := parseLevel(level)
+	lvl, err := ParseLevel(level)
 	if err != nil {
 		panic(err)
 	}
@@ -343,7 +346,7 @@ func defaultJSONHandler(lvl slog.Leveler, writer io.Writer) *slog.JSONHandler {
 
 func NewLoggerWithWriter(level string, writer io.Writer) Logger {
 	// Parse log level
-	lvl, err := parseLevel(level)
+	lvl, err := ParseLevel(level)
 	if err != nil {
 		panic(err)
 	}