feat: add timeout handler on FE (#3537)

* ✨ (frontend): Add TimeoutErrorComponent to handle timeout errors in API requests
🔧 (frontend): Add healthCheckTimeout state and setHealthCheckTimeout function to utilityStore for managing timeout errors in API requests

* 📝 (constants.ts): add constants for server health check intervals to improve code readability and maintainability
🐛 (use-get-health.ts): fix refetch interval value to use the newly added constant REFETCH_SERVER_HEALTH_INTERVAL for consistency and easier maintenance

* 📝 (api.tsx): Add utilityStore import to improve code organization
📝 (api.tsx): Add createNewError503 function to handle custom 503 errors
📝 (api.tsx): Add AxiosError import for type checking
📝 (api.tsx): Refactor error handling logic for authentication errors
📝 (use-get-health.ts): Add createNewError503 import for custom 503 errors
📝 (use-get-health.ts): Add AxiosError import for type checking
📝 (use-get-health.ts): Refactor error handling logic for server busy status
📝 (index.tsx): Add AxiosError import for type checking
📝 (index.tsx): Add useEffect and useState imports for state management
📝 (index.tsx): Refactor error handling logic for server status and retries
📝 (utilityStore.ts): Add retriesApiRequest state and setRetriesApiRequest function
📝 (axios-error-503.ts): Create function to generate custom 503 error responses
📝 (index.ts): Add retriesApiRequest state and setRetriesApiRequest function to UtilityStoreType

* 🔧 (utilityStore.ts): remove unused retriesApiRequest and setRetriesApiRequest functions to clean up code and improve maintainability
🔧 (index.ts): remove unused retriesApiRequest and setRetriesApiRequest types to keep type definitions consistent and up to date

* ✨ (nginx.conf): add new health endpoint to proxy_pass requests to the backend server for health checks

* ✨ (langflow): Add support for configuring the number of retries for the health check feature. This change introduces a new option `health_check_max_retries` that can be set via environment variable or command line argument to control the maximum number of retries for the health check process.

* check if value is none

docker/frontend/nginx.conf

@@ -20,6 +20,9 @@ server {
     location /health_check {
         proxy_pass __BACKEND_URL__;
     }
+    location /health {
+        proxy_pass __BACKEND_URL__;
+    }
 
     include /etc/nginx/extra-conf.d/*.conf;
 }

src/backend/base/langflow/__main__.py

@@ -130,6 +130,11 @@ def run(
         help="Defines the debounce time for the auto save.",
         envvar="LANGFLOW_AUTO_SAVING_INTERVAL",
     ),
+    health_check_max_retries: bool = typer.Option(
+        True,
+        help="Defines the number of retries for the health check.",
+        envvar="LANGFLOW_HEALTH_CHECK_MAX_RETRIES",
+    ),
 ):
     """
     Run Langflow.
@@ -149,6 +154,7 @@ def run(
         store=store,
         auto_saving=auto_saving,
         auto_saving_interval=auto_saving_interval,
+        health_check_max_retries=health_check_max_retries,
     )
     # create path object if path is provided
     static_files_dir: Optional[Path] = Path(path) if path else None

src/backend/base/langflow/api/v1/schemas.py

@@ -340,3 +340,4 @@ class ConfigResponse(BaseModel):
     frontend_timeout: int
     auto_saving: bool
     auto_saving_interval: int
+    health_check_max_retries: int

src/backend/base/langflow/services/settings/base.py

@@ -159,6 +159,8 @@ class Settings(BaseSettings):
     """If set to True, Langflow will auto save flows."""
     auto_saving_interval: int = 300
     """The interval in ms at which Langflow will auto save flows."""
+    health_check_max_retries: int = 5
+    """The maximum number of retries for the health check."""
 
     @field_validator("dev")
     @classmethod

src/backend/base/langflow/utils/util.py

@@ -430,6 +430,7 @@ def update_settings(
     store: bool = True,
     auto_saving: bool = True,
     auto_saving_interval: int = 300,
+    health_check_max_retries: int = 5,
 ):
     """Update the settings from a config file."""
     from langflow.services.utils import initialize_settings_service
@@ -456,9 +457,12 @@ def update_settings(
     if not auto_saving:
         logger.debug("Setting auto_saving to False")
         settings_service.settings.update_settings(auto_saving=False)
-    if auto_saving_interval:
+    if auto_saving_interval is not None:
         logger.debug(f"Setting auto_saving_interval to {auto_saving_interval}")
         settings_service.settings.update_settings(auto_saving_interval=auto_saving_interval)
+    if health_check_max_retries is not None:
+        logger.debug(f"Setting health_check_max_retries to {health_check_max_retries}")
+        settings_service.settings.update_settings(health_check_max_retries=health_check_max_retries)
 
 
 def is_class_method(func, cls):

src/frontend/src/components/timeoutErrorComponent/index.tsx

@@ -0,0 +1,37 @@
+import BaseModal from "../../modals/baseModal";
+import { fetchErrorComponentType } from "../../types/components";
+import IconComponent from "../genericIconComponent";
+import Loading from "../ui/loading";
+
+export default function TimeoutErrorComponent({
+  message,
+  description,
+  openModal,
+  setRetry,
+}: fetchErrorComponentType) {
+  return (
+    <>
+      <BaseModal
+        size="small-h-full"
+        open={openModal}
+        type="modal"
+        onSubmit={() => {
+          setRetry();
+        }}
+      >
+        <BaseModal.Content>
+          <div role="status" className="m-auto flex flex-col items-center">
+            <Loading className={`h-16 w-16`} />
+            <br></br>
+            <span className="text-lg text-primary">{message}</span>
+            <span className="text-center text-lg text-primary">
+              {description}
+            </span>
+          </div>
+        </BaseModal.Content>
+
+        <BaseModal.Footer />
+      </BaseModal>
+    </>
+  );
+}

src/frontend/src/constants/constants.ts

@@ -623,6 +623,10 @@ export const FETCH_ERROR_MESSAGE = "Couldn't establish a connection.";
 export const FETCH_ERROR_DESCRIPION =
   "Check if everything is working properly and try again.";
 
+export const TIMEOUT_ERROR_MESSAGE =
+  "Please wait a few seconds to server process your request.";
+export const TIMEOUT_ERROR_DESCRIPION = "Server is busy.";
+
 export const SIGN_UP_SUCCESS = "Account created! Await admin activation. ";
 
 export const API_PAGE_PARAGRAPH =
@@ -890,3 +894,6 @@ export const NODE_WIDTH = 400;
 export const NODE_HEIGHT = NODE_WIDTH * 3;
 
 export const SHORTCUT_KEYS = ["cmd", "ctrl", "alt", "shift"];
+
+export const SERVER_HEALTH_INTERVAL = 10000;
+export const REFETCH_SERVER_HEALTH_INTERVAL = 20000;

src/frontend/src/controllers/API/api.tsx

@@ -1,5 +1,6 @@
 import { LANGFLOW_ACCESS_TOKEN } from "@/constants/constants";
 import useAuthStore from "@/stores/authStore";
+import { useUtilityStore } from "@/stores/utilityStore";
 import axios, { AxiosError, AxiosInstance, AxiosRequestConfig } from "axios";
 import { useContext, useEffect } from "react";
 import { Cookies } from "react-cookie";
@@ -29,10 +30,10 @@ function ApiInterceptor() {
     const interceptor = api.interceptors.response.use(
       (response) => response,
       async (error: AxiosError) => {
-        if (
-          error?.response?.status === 403 ||
-          error?.response?.status === 401
-        ) {
+        const isAuthenticationError =
+          error?.response?.status === 403 || error?.response?.status === 401;
+
+        if (isAuthenticationError) {
           if (!autoLogin) {
             if (error?.config?.url?.includes("github")) {
               return Promise.reject(error);
@@ -50,11 +51,10 @@ function ApiInterceptor() {
             }
           }
         }
+
         await clearBuildVerticesState(error);
-        if (
-          error?.response?.status !== 401 &&
-          error?.response?.status !== 403
-        ) {
+
+        if (!isAuthenticationError) {
           return Promise.reject(error);
         }
       },

src/frontend/src/controllers/API/queries/config/use-get-config.ts

@@ -7,6 +7,7 @@ export interface ConfigResponse {
   frontend_timeout: number;
   auto_saving: boolean;
   auto_saving_interval: number;
+  health_check_max_retries: number;
 }
 
 export const useGetConfigQuery: useQueryFunctionType<

src/frontend/src/controllers/API/queries/health/use-get-health.ts

@@ -1,4 +1,11 @@
+import {
+  REFETCH_SERVER_HEALTH_INTERVAL,
+  SERVER_HEALTH_INTERVAL,
+} from "@/constants/constants";
+import { useUtilityStore } from "@/stores/utilityStore";
+import { createNewError503 } from "@/types/factory/axios-error-503";
 import { keepPreviousData } from "@tanstack/react-query";
+import { AxiosError, AxiosHeaders } from "axios";
 import { useQueryFunctionType } from "../../../../types/api";
 import { api } from "../../api";
 import { UseRequestProcessor } from "../../services/request-processor";
@@ -16,20 +23,44 @@ export const useGetHealthQuery: useQueryFunctionType<
   getHealthResponse
 > = (_, options) => {
   const { query } = UseRequestProcessor();
-
+  const setHealthCheckTimeout = useUtilityStore(
+    (state) => state.setHealthCheckTimeout,
+  );
+  const healthCheckTimeout = useUtilityStore(
+    (state) => state.healthCheckTimeout,
+  );
   /**
    * Fetches the health status of the API.
    *
    * @returns {Promise<AxiosResponse<TransactionsResponse>>} A promise that resolves to an AxiosResponse containing the health status.
    */
   async function getHealthFn() {
-    return (await api.get("/health_check")).data;
-    // Health is the only endpoint that doesn't require /api/v1
+    try {
+      const timeoutPromise = new Promise<never>((_, reject) =>
+        setTimeout(() => reject(createNewError503()), SERVER_HEALTH_INTERVAL),
+      );
+
+      const apiPromise = api.get<{ data: getHealthResponse }>("/health");
+      const response = await Promise.race([apiPromise, timeoutPromise]);
+      setHealthCheckTimeout(null);
+      return response.data;
+    } catch (error) {
+      const isServerBusy =
+        healthCheckTimeout === null &&
+        (error as AxiosError)?.response?.status === 503;
+
+      if (isServerBusy) {
+        setHealthCheckTimeout("timeout");
+      } else if (healthCheckTimeout === null) {
+        setHealthCheckTimeout("serverDown");
+      }
+      throw error;
+    }
   }
 
   const queryResult = query(["useGetHealthQuery"], getHealthFn, {
     placeholderData: keepPreviousData,
-    refetchInterval: 20000,
+    refetchInterval: REFETCH_SERVER_HEALTH_INTERVAL,
     retry: false,
     ...options,
   });

src/frontend/src/hooks/use-save-config.ts

@@ -9,6 +9,9 @@ function useSaveConfig() {
   const setAutoSavingInterval = useFlowsManagerStore(
     (state) => state.setAutoSavingInterval,
   );
+  const setHealthCheckMaxRetries = useFlowsManagerStore(
+    (state) => state.setHealthCheckMaxRetries,
+  );
 
   useEffect(() => {
     if (data) {
@@ -19,6 +22,7 @@ function useSaveConfig() {
       axios.defaults.timeout = timeoutInMilliseconds;
       setAutoSaving(data.auto_saving);
       setAutoSavingInterval(data.auto_saving_interval);
+      setHealthCheckMaxRetries(data.health_check_max_retries);
     }
   }, [data]);
 }

src/frontend/src/pages/AppWrapperPage/index.tsx

@@ -2,14 +2,20 @@ import AlertDisplayArea from "@/alerts/displayArea";
 import CrashErrorComponent from "@/components/crashErrorComponent";
 import FetchErrorComponent from "@/components/fetchErrorComponent";
 import LoadingComponent from "@/components/loadingComponent";
+import TimeoutErrorComponent from "@/components/timeoutErrorComponent";
 import {
   FETCH_ERROR_DESCRIPION,
   FETCH_ERROR_MESSAGE,
+  TIMEOUT_ERROR_DESCRIPION,
+  TIMEOUT_ERROR_MESSAGE,
 } from "@/constants/constants";
 import { useGetHealthQuery } from "@/controllers/API/queries/health";
 import useTrackLastVisitedPath from "@/hooks/use-track-last-visited-path";
 import useFlowsManagerStore from "@/stores/flowsManagerStore";
+import { useUtilityStore } from "@/stores/utilityStore";
 import { cn } from "@/utils/utils";
+import { AxiosError } from "axios";
+import { useEffect, useMemo, useState } from "react";
 import { ErrorBoundary } from "react-error-boundary";
 import { Outlet } from "react-router-dom";
 
@@ -17,12 +23,86 @@ export function AppWrapperPage() {
   useTrackLastVisitedPath();
 
   const isLoading = useFlowsManagerStore((state) => state.isLoading);
+
+  const healthCheckMaxRetries = useFlowsManagerStore(
+    (state) => state.healthCheckMaxRetries,
+  );
+
+  const healthCheckTimeout = useUtilityStore(
+    (state) => state.healthCheckTimeout,
+  );
+
   const {
     data: healthData,
     isFetching: fetchingHealth,
     isError: isErrorHealth,
+    error,
     refetch,
   } = useGetHealthQuery();
+
+  const isServerDown =
+    isErrorHealth ||
+    (healthData && Object.values(healthData).some((value) => value !== "ok")) ||
+    healthCheckTimeout === "serverDown";
+
+  const isTimeoutResponseServer = healthCheckTimeout === "timeout";
+
+  const [retryCount, setRetryCount] = useState(0);
+
+  console.log(healthCheckMaxRetries);
+
+  useEffect(() => {
+    const isServerBusy =
+      (error as AxiosError)?.response?.status === 503 ||
+      (error as AxiosError)?.response?.status === 429;
+
+    if (isServerBusy && isErrorHealth) {
+      const maxRetries = healthCheckMaxRetries;
+      if (retryCount < maxRetries) {
+        const delay = Math.pow(2, retryCount) * 1000;
+        const timer = setTimeout(() => {
+          refetch();
+          setRetryCount(retryCount + 1);
+        }, delay);
+
+        return () => clearTimeout(timer);
+      }
+    } else {
+      setRetryCount(0);
+    }
+  }, [isErrorHealth, retryCount, refetch]);
+
+  const modalErrorComponent = useMemo(() => {
+    switch (healthCheckTimeout) {
+      case "serverDown":
+        return (
+          <FetchErrorComponent
+            description={FETCH_ERROR_DESCRIPION}
+            message={FETCH_ERROR_MESSAGE}
+            openModal={isServerDown}
+            setRetry={() => {
+              refetch();
+            }}
+            isLoadingHealth={fetchingHealth}
+          ></FetchErrorComponent>
+        );
+      case "timeout":
+        return (
+          <TimeoutErrorComponent
+            description={TIMEOUT_ERROR_MESSAGE}
+            message={TIMEOUT_ERROR_DESCRIPION}
+            openModal={isTimeoutResponseServer}
+            setRetry={() => {
+              refetch();
+            }}
+            isLoadingHealth={fetchingHealth}
+          ></TimeoutErrorComponent>
+        );
+      default:
+        return null;
+    }
+  }, [healthCheckTimeout, fetchingHealth]);
+
   return (
     <div className="flex h-full flex-col">
       <ErrorBoundary
@@ -32,21 +112,7 @@ export function AppWrapperPage() {
         FallbackComponent={CrashErrorComponent}
       >
         <>
-          {
-            <FetchErrorComponent
-              description={FETCH_ERROR_DESCRIPION}
-              message={FETCH_ERROR_MESSAGE}
-              openModal={
-                isErrorHealth ||
-                (healthData &&
-                  Object.values(healthData).some((value) => value !== "ok"))
-              }
-              setRetry={() => {
-                refetch();
-              }}
-              isLoadingHealth={fetchingHealth}
-            ></FetchErrorComponent>
-          }
+          {modalErrorComponent}
 
           <div
             className={cn(

src/frontend/src/stores/flowsManagerStore.ts

@@ -17,6 +17,9 @@ const past = {};
 const future = {};
 
 const useFlowsManagerStore = create<FlowsManagerStoreType>((set, get) => ({
+  healthCheckMaxRetries: 5,
+  setHealthCheckMaxRetries: (healthCheckMaxRetries: number) =>
+    set({ healthCheckMaxRetries }),
   autoSaving: true,
   setAutoSaving: (autoSaving: boolean) => set({ autoSaving }),
   autoSavingInterval: SAVE_DEBOUNCE_TIME,

src/frontend/src/stores/utilityStore.ts

@@ -1,6 +1,7 @@
+import { UtilityStoreType } from "@/types/zustand/utility";
 import { create } from "zustand";
 
-export const useUtilityStore = create<any>((set, get) => ({
+export const useUtilityStore = create<UtilityStoreType>((set, get) => ({
   selectedItems: [],
   setSelectedItems: (itemId) => {
     if (get().selectedItems.includes(itemId)) {
@@ -11,4 +12,7 @@ export const useUtilityStore = create<any>((set, get) => ({
       set({ selectedItems: get().selectedItems.concat(itemId) });
     }
   },
+  healthCheckTimeout: null,
+  setHealthCheckTimeout: (timeout: string | null) =>
+    set({ healthCheckTimeout: timeout }),
 }));

src/frontend/src/types/factory/axios-error-503.ts

@@ -0,0 +1,23 @@
+import { AxiosError, AxiosHeaders } from "axios";
+
+export const createNewError503 = (): AxiosError => {
+  const headers = new AxiosHeaders({
+    "Content-Type": "application/json",
+  });
+
+  const config = {
+    url: "/",
+    method: "get",
+    headers: headers,
+  };
+
+  const error = new AxiosError("Server Busy", "ECONNABORTED", config, null, {
+    status: 503,
+    statusText: "Service Unavailable",
+    data: "Server is currently busy, please try again later.",
+    headers: {},
+    config: config,
+  });
+
+  return error;
+};

src/frontend/src/types/zustand/flowsManager/index.ts

@@ -24,6 +24,8 @@ export type FlowsManagerStoreType = {
   setSelectedFlowsComponentsCards: (selected: string[]) => void;
   autoSavingInterval: number;
   setAutoSavingInterval: (autoSavingInterval: number) => void;
+  healthCheckMaxRetries: number;
+  setHealthCheckMaxRetries: (healthCheckMaxRetries: number) => void;
 };
 
 export type UseUndoRedoOptions = {

src/frontend/src/types/zustand/utility/index.ts

@@ -0,0 +1,6 @@
+export type UtilityStoreType = {
+  selectedItems: any[];
+  setSelectedItems: (itemId: any) => void;
+  healthCheckTimeout: string | null;
+  setHealthCheckTimeout: (timeout: string | null) => void;
+};