Handle empty log-format gracefully

client/pkg/logutil/log_format.go

@@ -29,6 +29,8 @@ func ConvertToZapFormat(format string) (string, error) {
 	case ConsoleLogFormat:
 		return ConsoleLogFormat, nil
 	case JsonLogFormat:
+		return JsonLogFormat, nil
+	case "":
 		return DefaultLogFormat, nil
 	default:
 		return "", fmt.Errorf("unknown log format: %s, supported values json, console", format)

client/pkg/logutil/log_format_test.go

@@ -26,7 +26,8 @@ func TestLogFormat(t *testing.T) {
 	}{
 		{"json", JsonLogFormat, false},
 		{"console", ConsoleLogFormat, false},
-		{"", "", true},
+		{"", JsonLogFormat, false},
+		{"konsole", "", true},
 	}
 
 	for i, tt := range tests {