fix(user): allow re-login by removing existing session if user is already logged in

fix(main): conditionally initialize and connect to watchdog based on configuration

fix(instance): remove unused userID variable and commented debug logs in ListInstancesHandler

handlers/user.go

@@ -182,9 +182,23 @@ func LoginHandler(w http.ResponseWriter, r *http.Request) {
 
 	existingTokenInfo, err := session.GetTokenInfo(user.UserID)
 	if err == nil && existingTokenInfo != nil {
-		utils.SendErrorResponse(w, http.StatusConflict, "User is already logged in")
-		postLog.Warning(fmt.Sprintf("[LoginHandler] Login failed: user \"%s\" is already logged in", req.Username))
-		return
+		// If the user is already logged in, then remove the existing session to allow the new login, instead of returning an error.
+		sessionTokenMux := session.GetSessionTokenMap()
+		sessionTokenMux.RLock()
+		sessionID := ""
+		for sid, tokenLogout := range session.GetSessionTokenMapSnapshot() {
+			if tokenLogout == existingTokenInfo.Token {
+				sessionID = sid
+				break
+			}
+		}
+		sessionTokenMux.RUnlock()
+		if err := session.RemoveSession(sessionID); err != nil {
+			utils.SendErrorResponse(w, http.StatusInternalServerError, "Failed to logout")
+			postLog.Error(fmt.Sprintf("[LoginHandler] Failed to logout user [%d]%s: %v", user.UserID, session.GetUsernameByID(user.UserID), err))
+			return
+		}
+		postLog.Info(fmt.Sprintf("[LoginHandler] User \"%s\" is already logged in, remove previous session", req.Username))
 	}
 
 	token, err := session.GenerateToken(user.UserID)