add failover check ctx

pro/controllers/failover.go

@@ -29,6 +29,8 @@ func FailOverHandlers(r *mux.Router) {
 		Methods(http.MethodPost)
 	r.HandleFunc("/api/v1/node/{nodeid}/failover_me", controller.Authorize(true, false, "host", http.HandlerFunc(failOverME))).
 		Methods(http.MethodPost)
+	r.HandleFunc("/api/v1/node/{nodeid}/failover_check", controller.Authorize(true, false, "host", http.HandlerFunc(checkfailOverCtx))).
+		Methods(http.MethodGet)
 }
 
 // @Summary     Get failover node
@@ -293,3 +295,136 @@ func failOverME(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
 	logic.ReturnSuccessResponse(w, r, "relayed successfully")
 }
+
+// @Summary     Failover me
+// @Router      /api/v1/node/{nodeid}/failover_check [post]
+// @Tags        PRO
+// @Param       nodeid path string true "Node ID"
+// @Accept      json
+// @Param       body body models.FailOverMeReq true "Failover request"
+// @Success     200 {object} models.SuccessResponse
+// @Failure     400 {object} models.ErrorResponse
+// @Failure     500 {object} models.ErrorResponse
+func checkfailOverCtx(w http.ResponseWriter, r *http.Request) {
+	var params = mux.Vars(r)
+	nodeid := params["nodeid"]
+	// confirm host exists
+	node, err := logic.GetNodeByID(nodeid)
+	if err != nil {
+		logger.Log(0, r.Header.Get("user"), "failed to get node:", err.Error())
+		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
+		return
+	}
+	host, err := logic.GetHost(node.HostID.String())
+	if err != nil {
+		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
+		return
+	}
+
+	failOverNode, exists := proLogic.FailOverExists(node.Network)
+	if !exists {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(
+				fmt.Errorf("req-from: %s, failover node doesn't exist in the network", host.Name),
+				"badrequest",
+			),
+		)
+		return
+	}
+	var failOverReq models.FailOverMeReq
+	err = json.NewDecoder(r.Body).Decode(&failOverReq)
+	if err != nil {
+		logger.Log(0, r.Header.Get("user"), "error decoding request body: ", err.Error())
+		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
+		return
+	}
+	peerNode, err := logic.GetNodeByID(failOverReq.NodeID)
+	if err != nil {
+		slog.Error("peer not found: ", "nodeid", failOverReq.NodeID, "error", err)
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(errors.New("peer not found"), "badrequest"),
+		)
+		return
+	}
+	if peerNode.IsFailOver {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(errors.New("peer is acting as failover"), "badrequest"),
+		)
+		return
+	}
+	if node.IsFailOver {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(errors.New("node is acting as failover"), "badrequest"),
+		)
+		return
+	}
+	if peerNode.IsFailOver {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(errors.New("peer is acting as failover"), "badrequest"),
+		)
+		return
+	}
+	if node.IsRelayed && node.RelayedBy == peerNode.ID.String() {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(errors.New("node is relayed by peer node"), "badrequest"),
+		)
+		return
+	}
+	if node.IsRelay && peerNode.RelayedBy == node.ID.String() {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(errors.New("node acting as relay for the peer node"), "badrequest"),
+		)
+		return
+	}
+	if node.IsInternetGateway && peerNode.InternetGwID == node.ID.String() {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(
+				errors.New("node acting as internet gw for the peer node"),
+				"badrequest",
+			),
+		)
+		return
+	}
+	if node.InternetGwID != "" && node.InternetGwID == peerNode.ID.String() {
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(
+				errors.New("node using a internet gw by the peer node"),
+				"badrequest",
+			),
+		)
+		return
+	}
+
+	err = proLogic.CheckFailOverCtx(failOverNode, node, peerNode)
+	if err != nil {
+		slog.Error("failed to create failover", "id", node.ID.String(),
+			"network", node.Network, "error", err)
+		logic.ReturnErrorResponse(
+			w,
+			r,
+			logic.FormatError(fmt.Errorf("failed to create failover: %v", err), "internal"),
+		)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	logic.ReturnSuccessResponse(w, r, "failover can be set")
+}

pro/logic/failover.go

@@ -38,6 +38,24 @@ func InitFailOverCache() {
 		}
 	}
 }
+
+func CheckFailOverCtx(failOverNode, victimNode, peerNode models.Node) error {
+	failOverCtxMutex.RLock()
+	defer failOverCtxMutex.RUnlock()
+	if peerNode.FailOverPeers == nil {
+		return nil
+	}
+	if victimNode.FailOverPeers == nil {
+		return nil
+	}
+	_, peerHasFailovered := peerNode.FailOverPeers[victimNode.ID.String()]
+	_, victimHasFailovered := victimNode.FailOverPeers[peerNode.ID.String()]
+	if peerHasFailovered && victimHasFailovered &&
+		victimNode.FailedOverBy == failOverNode.ID && peerNode.FailedOverBy == failOverNode.ID {
+		return errors.New("failover ctx is already set")
+	}
+	return nil
+}
 func SetFailOverCtx(failOverNode, victimNode, peerNode models.Node) error {
 	failOverCtxMutex.Lock()
 	defer failOverCtxMutex.Unlock()
@@ -57,9 +75,6 @@ func SetFailOverCtx(failOverNode, victimNode, peerNode models.Node) error {
 	victimNode.FailOverPeers[peerNode.ID.String()] = struct{}{}
 	victimNode.FailedOverBy = failOverNode.ID
 	peerNode.FailedOverBy = failOverNode.ID
-	if err := logic.UpsertNode(&failOverNode); err != nil {
-		return err
-	}
 	if err := logic.UpsertNode(&victimNode); err != nil {
 		return err
 	}