Cache token for thundering hurd

server/lib/tokenCache.ts

@@ -0,0 +1,22 @@
+/**
+ * Returns a cached plaintext token from Redis if one exists and decrypts
+ * cleanly, otherwise calls `createSession` to mint a fresh token, stores the
+ * encrypted value in Redis with the given TTL, and returns it.
+ *
+ * Failures at the Redis layer are non-fatal – the function always falls
+ * through to session creation so the caller is never blocked by a Redis outage.
+ *
+ * @param cacheKey   Unique Redis key, e.g. `"newt:token_cache:abc123"`
+ * @param secret     Server secret used for AES encryption/decryption
+ * @param ttlSeconds Cache TTL in seconds (should match session expiry)
+ * @param createSession Factory that mints a new session and returns its raw token
+ */
+export async function getOrCreateCachedToken(
+    cacheKey: string,
+    secret: string,
+    ttlSeconds: number,
+    createSession: () => Promise<string>
+): Promise<string> {
+    const token = await createSession();
+    return token;
+}

server/private/lib/cache.ts

@@ -1,3 +1,16 @@
+/*
+ * This file is part of a proprietary work.
+ *
+ * Copyright (c) 2025 Fossorial, Inc.
+ * All rights reserved.
+ *
+ * This file is licensed under the Fossorial Commercial License.
+ * You may not use this file except in compliance with the License.
+ * Unauthorized use, copying, modification, or distribution is strictly prohibited.
+ *
+ * This file is not licensed under the AGPLv3.
+ */
+
 import NodeCache from "node-cache";
 import logger from "@server/logger";
 import { redisManager } from "@server/private/lib/redis";

server/private/lib/tokenCache.ts

@@ -0,0 +1,77 @@
+/*
+ * This file is part of a proprietary work.
+ *
+ * Copyright (c) 2025 Fossorial, Inc.
+ * All rights reserved.
+ *
+ * This file is licensed under the Fossorial Commercial License.
+ * You may not use this file except in compliance with the License.
+ * Unauthorized use, copying, modification, or distribution is strictly prohibited.
+ *
+ * This file is not licensed under the AGPLv3.
+ */
+
+import redisManager from "#dynamic/lib/redis";
+import { encrypt, decrypt } from "@server/lib/crypto";
+import logger from "@server/logger";
+
+/**
+ * Returns a cached plaintext token from Redis if one exists and decrypts
+ * cleanly, otherwise calls `createSession` to mint a fresh token, stores the
+ * encrypted value in Redis with the given TTL, and returns it.
+ *
+ * Failures at the Redis layer are non-fatal – the function always falls
+ * through to session creation so the caller is never blocked by a Redis outage.
+ *
+ * @param cacheKey   Unique Redis key, e.g. `"newt:token_cache:abc123"`
+ * @param secret     Server secret used for AES encryption/decryption
+ * @param ttlSeconds Cache TTL in seconds (should match session expiry)
+ * @param createSession Factory that mints a new session and returns its raw token
+ */
+export async function getOrCreateCachedToken(
+    cacheKey: string,
+    secret: string,
+    ttlSeconds: number,
+    createSession: () => Promise<string>
+): Promise<string> {
+    if (redisManager.isRedisEnabled()) {
+        try {
+            const cached = await redisManager.get(cacheKey);
+            if (cached) {
+                const token = decrypt(cached, secret);
+                if (token) {
+                    logger.debug(`Token cache hit for key: ${cacheKey}`);
+                    return token;
+                }
+                // Decryption produced an empty string – treat as a miss
+                logger.warn(
+                    `Token cache decryption returned empty string for key: ${cacheKey}, treating as miss`
+                );
+            }
+        } catch (e) {
+            logger.warn(
+                `Token cache read/decrypt failed for key ${cacheKey}, falling through to session creation:`,
+                e
+            );
+        }
+    }
+
+    const token = await createSession();
+
+    if (redisManager.isRedisEnabled()) {
+        try {
+            const encrypted = encrypt(token, secret);
+            await redisManager.set(cacheKey, encrypted, ttlSeconds);
+            logger.debug(
+                `Token cached in Redis for key: ${cacheKey} (TTL ${ttlSeconds}s)`
+            );
+        } catch (e) {
+            logger.warn(
+                `Token cache write failed for key ${cacheKey} (session was still created):`,
+                e
+            );
+        }
+    }
+
+    return token;
+}

server/private/routers/remoteExitNode/getRemoteExitNodeToken.ts

@@ -23,8 +23,10 @@ import { z } from "zod";
 import { fromError } from "zod-validation-error";
 import {
     createRemoteExitNodeSession,
-    validateRemoteExitNodeSessionToken
+    validateRemoteExitNodeSessionToken,
+    EXPIRES
 } from "#private/auth/sessions/remoteExitNode";
+import { getOrCreateCachedToken } from "@server/private/lib/tokenCache";
 import { verifyPassword } from "@server/auth/password";
 import logger from "@server/logger";
 import config from "@server/lib/config";
@@ -103,14 +105,23 @@ export async function getRemoteExitNodeToken(
             );
         }
 
-        const resToken = generateSessionToken();
+        // Return a cached token if one exists to prevent thundering herd on
-        await createRemoteExitNodeSession(
+        // simultaneous restarts; falls back to creating a fresh session when
-            resToken,
+        // Redis is unavailable or the cache has expired.
-            existingRemoteExitNode.remoteExitNodeId
+        const resToken = await getOrCreateCachedToken(
+            `remote_exit_node:token_cache:${existingRemoteExitNode.remoteExitNodeId}`,
+            config.getRawConfig().server.secret!,
+            Math.floor(EXPIRES / 1000),
+            async () => {
+                const token = generateSessionToken();
+                await createRemoteExitNodeSession(
+                    token,
+                    existingRemoteExitNode.remoteExitNodeId
+                );
+                return token;
+            }
         );
 
-        // logger.debug(`Created RemoteExitNode token response: ${JSON.stringify(resToken)}`);
-
         return response<{ token: string }>(res, {
             data: {
                 token: resToken

server/routers/newt/getNewtToken.ts

@@ -1,6 +1,8 @@
 import { generateSessionToken } from "@server/auth/sessions/app";
 import { db, newtSessions } from "@server/db";
 import { newts } from "@server/db";
+import { getOrCreateCachedToken } from "#dynamic/lib/tokenCache";
+import { EXPIRES } from "@server/auth/sessions/newt";
 import HttpCode from "@server/types/HttpCode";
 import response from "@server/lib/response";
 import { eq } from "drizzle-orm";
@@ -92,9 +94,19 @@ export async function getNewtToken(
             );
         }
 
-        // otherwise generate a new one
+        // Return a cached token if one exists to prevent thundering herd on
-        const resToken = generateSessionToken();
+        // simultaneous restarts; falls back to creating a fresh session when
-        await createNewtSession(resToken, existingNewt.newtId);
+        // Redis is unavailable or the cache has expired.
+        const resToken = await getOrCreateCachedToken(
+            `newt:token_cache:${existingNewt.newtId}`,
+            config.getRawConfig().server.secret!,
+            Math.floor(EXPIRES / 1000),
+            async () => {
+                const token = generateSessionToken();
+                await createNewtSession(token, existingNewt.newtId);
+                return token;
+            }
+        );
 
         return response<{ token: string; serverVersion: string }>(res, {
             data: {

server/routers/olm/getOlmToken.ts

@@ -20,8 +20,10 @@ import { z } from "zod";
 import { fromError } from "zod-validation-error";
 import {
     createOlmSession,
-    validateOlmSessionToken
+    validateOlmSessionToken,
+    EXPIRES
 } from "@server/auth/sessions/olm";
+import { getOrCreateCachedToken } from "#dynamic/lib/tokenCache";
 import { verifyPassword } from "@server/auth/password";
 import logger from "@server/logger";
 import config from "@server/lib/config";
@@ -132,8 +134,19 @@ export async function getOlmToken(
 
         logger.debug("Creating new olm session token");
 
-        const resToken = generateSessionToken();
+        // Return a cached token if one exists to prevent thundering herd on
-        await createOlmSession(resToken, existingOlm.olmId);
+        // simultaneous restarts; falls back to creating a fresh session when
+        // Redis is unavailable or the cache has expired.
+        const resToken = await getOrCreateCachedToken(
+            `olm:token_cache:${existingOlm.olmId}`,
+            config.getRawConfig().server.secret!,
+            Math.floor(EXPIRES / 1000),
+            async () => {
+                const token = generateSessionToken();
+                await createOlmSession(token, existingOlm.olmId);
+                return token;
+            }
+        );
 
         let clientIdToUse;
         if (orgId) {