fix(webapp): fix Redis connection leak in realtime streams and broken abort signal propagation

Pool Redis connections for non-blocking ops (ingestData, appendPart, getLastChunkIndex)
using a shared singleton instead of new Redis() per request. Use redis.disconnect()
for immediate teardown in streamResponse cleanup. Add 15s inactivity timeout fallback.

Fix broken request.signal in Remix/Express by wiring Express res.on('close') to an
AbortController via httpAsyncStorage. All SSE/streaming routes now use
getRequestAbortSignal() which fires reliably on client disconnect, bypassing the
Node.js undici GC bug (nodejs/node#55428) that severs the signal chain.

Author: ericallam

apps/webapp/CLAUDE.md

@@ -59,6 +59,17 @@ Use the `chrome-devtools` MCP server to visually verify local dashboard changes.
 Routes use Remix flat-file convention with dot-separated segments:
 `api.v1.tasks.$taskId.trigger.ts` -> `/api/v1/tasks/:taskId/trigger`
 
+## Abort Signals
+
+**Never use `request.signal`** for detecting client disconnects. It is broken due to a Node.js bug ([nodejs/node#55428](https://github.com/nodejs/node/issues/55428)) where the AbortSignal chain is severed when Remix internally clones the Request object. Instead, use `getRequestAbortSignal()` from `app/services/httpAsyncStorage.server.ts`, which is wired directly to Express `res.on("close")` and fires reliably.
+
+```typescript
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
+
+// In route handlers, SSE streams, or any server-side code:
+const signal = getRequestAbortSignal();
+```
+
 ## Environment Variables
 
 Access via `env` export from `app/env.server.ts`. **Never use `process.env` directly.**

apps/webapp/app/presenters/v3/TasksStreamPresenter.server.ts

@@ -1,6 +1,7 @@
 import { type TaskRunAttempt } from "@trigger.dev/database";
 import { eventStream } from "remix-utils/sse/server";
 import { type PrismaClient, prisma } from "~/db.server";
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
 import { logger } from "~/services/logger.server";
 import { projectPubSub } from "~/v3/services/projectPubSub.server";
 
@@ -63,7 +64,9 @@ export class TasksStreamPresenter {
 
     const subscriber = await projectPubSub.subscribe(`project:${project.id}:*`);
 
-    return eventStream(request.signal, (send, close) => {
+    const signal = getRequestAbortSignal();
+
+    return eventStream(signal, (send, close) => {
       const safeSend = (args: { event?: string; data: string }) => {
         try {
           send(args);
@@ -95,7 +98,7 @@ export class TasksStreamPresenter {
       });
 
       pinger = setInterval(() => {
-        if (request.signal.aborted) {
+        if (signal.aborted) {
           return close();
         }
 

apps/webapp/app/routes/realtime.v1.streams.$runId.$streamId.ts

@@ -1,6 +1,7 @@
 import { type ActionFunctionArgs } from "@remix-run/server-runtime";
 import { z } from "zod";
 import { $replica } from "~/db.server";
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
 import { getRealtimeStreamInstance } from "~/services/realtime/v1StreamsGlobal.server";
 import { createLoaderApiRoute } from "~/services/routeBuilders/apiBuilder.server";
 import { AuthenticatedEnvironment } from "~/services/apiAuth.server";
@@ -129,7 +130,7 @@ export const loader = createLoaderApiRoute(
       run.realtimeStreamsVersion
     );
 
-    return realtimeStream.streamResponse(request, run.friendlyId, params.streamId, request.signal, {
+    return realtimeStream.streamResponse(request, run.friendlyId, params.streamId, getRequestAbortSignal(), {
       lastEventId,
       timeoutInSeconds,
     });

apps/webapp/app/routes/realtime.v1.streams.$runId.input.$streamId.ts

@@ -1,6 +1,7 @@
 import { json } from "@remix-run/server-runtime";
 import { z } from "zod";
 import { $replica } from "~/db.server";
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
 import {
   getInputStreamWaitpoint,
   deleteInputStreamWaitpoint,
@@ -162,7 +163,7 @@ const loader = createLoaderApiRoute(
       request,
       run.friendlyId,
       `$trigger.input:${params.streamId}`,
-      request.signal,
+      getRequestAbortSignal(),
       {
         lastEventId,
         timeoutInSeconds,

apps/webapp/app/routes/resources.orgs.$organizationSlug.projects.$projectParam.env.$envParam.runs.$runParam.streams.$streamKey/route.tsx

@@ -21,6 +21,7 @@ import { $replica } from "~/db.server";
 import { useEnvironment } from "~/hooks/useEnvironment";
 import { useOrganization } from "~/hooks/useOrganizations";
 import { useProject } from "~/hooks/useProject";
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
 import { getRealtimeStreamInstance } from "~/services/realtime/v1StreamsGlobal.server";
 import { requireUserId } from "~/services/session.server";
 import { cn } from "~/utils/cn";
@@ -89,7 +90,7 @@ export const loader = async ({ request, params }: LoaderFunctionArgs) => {
     run.realtimeStreamsVersion
   );
 
-  return realtimeStream.streamResponse(request, run.friendlyId, streamKey, request.signal, {
+  return realtimeStream.streamResponse(request, run.friendlyId, streamKey, getRequestAbortSignal(), {
     lastEventId,
   });
 };

apps/webapp/app/routes/resources.orgs.$organizationSlug.projects.$projectParam.env.$envParam.test.ai-generate-payload.tsx

@@ -5,6 +5,7 @@ import { z } from "zod";
 import { env } from "~/env.server";
 import { findProjectBySlug } from "~/models/project.server";
 import { findEnvironmentBySlug } from "~/models/runtimeEnvironment.server";
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
 import { requireUserId } from "~/services/session.server";
 import { EnvironmentParamSchema } from "~/utils/pathBuilder";
 import { inflate } from "node:zlib";
@@ -92,7 +93,7 @@ export async function action({ request, params }: ActionFunctionArgs) {
         const result = streamText({
           model: openai(env.AI_RUN_FILTER_MODEL ?? "gpt-5-mini"),
           temperature: 1,
-          abortSignal: request.signal,
+          abortSignal: getRequestAbortSignal(),
           system: systemPrompt,
           prompt,
           tools: {

apps/webapp/app/services/httpAsyncStorage.server.ts

@@ -5,6 +5,7 @@ export type HttpLocalStorage = {
   path: string;
   host: string;
   method: string;
+  abortController: AbortController;
 };
 
 const httpLocalStorage = new AsyncLocalStorage<HttpLocalStorage>();
@@ -18,3 +19,15 @@ export function runWithHttpContext<T>(context: HttpLocalStorage, fn: () => T): T
 export function getHttpContext(): HttpLocalStorage | undefined {
   return httpLocalStorage.getStore();
 }
+
+// Fallback signal that is never aborted, safe for tests and non-Express contexts.
+const neverAbortedSignal = new AbortController().signal;
+
+/**
+ * Returns an AbortSignal wired to the Express response's "close" event.
+ * This bypasses the broken request.signal chain in @remix-run/express
+ * (caused by Node.js undici GC bug nodejs/node#55428).
+ */
+export function getRequestAbortSignal(): AbortSignal {
+  return httpLocalStorage.getStore()?.abortController.signal ?? neverAbortedSignal;
+}

apps/webapp/app/services/realtime/redisRealtimeStreams.server.ts

@@ -23,10 +23,23 @@ type StreamChunk =
 export class RedisRealtimeStreams implements StreamIngestor, StreamResponder {
   private logger: Logger;
   private inactivityTimeoutMs: number;
+  // Shared connection for short-lived non-blocking operations (XADD, XREVRANGE, EXPIRE).
+  // Lazily created on first use so we don't open a connection if only streamResponse is called.
+  private _sharedRedis: Redis | undefined;
 
   constructor(private options: RealtimeStreamsOptions) {
     this.logger = options.logger ?? new Logger("RedisRealtimeStreams", options.logLevel ?? "info");
-    this.inactivityTimeoutMs = options.inactivityTimeoutMs ?? 60000; // Default: 60 seconds
+    this.inactivityTimeoutMs = options.inactivityTimeoutMs ?? 15000; // Default: 15 seconds
+  }
+
+  private get sharedRedis(): Redis {
+    if (!this._sharedRedis) {
+      this._sharedRedis = new Redis({
+        ...this.options.redis,
+        connectionName: "realtime:shared",
+      });
+    }
+    return this._sharedRedis;
   }
 
   async initializeStream(
@@ -43,7 +56,7 @@ export class RedisRealtimeStreams implements StreamIngestor, StreamResponder {
     signal: AbortSignal,
     options?: StreamResponseOptions
   ): Promise<Response> {
-    const redis = new Redis(this.options.redis ?? {});
+    const redis = new Redis({ ...this.options.redis, connectionName: "realtime:streamResponse" });
     const streamKey = `stream:${runId}:${streamId}`;
     let isCleanedUp = false;
 
@@ -269,7 +282,10 @@ export class RedisRealtimeStreams implements StreamIngestor, StreamResponder {
     async function cleanup() {
       if (isCleanedUp) return;
       isCleanedUp = true;
-      await redis.quit().catch(console.error);
+      // disconnect() tears down the TCP socket immediately, which causes any
+      // pending XREAD BLOCK to reject right away instead of waiting for the
+      // block timeout to elapse.  quit() would queue behind the blocking command.
+      redis.disconnect();
     }
 
     signal.addEventListener("abort", cleanup, { once: true });
@@ -290,22 +306,12 @@ export class RedisRealtimeStreams implements StreamIngestor, StreamResponder {
     clientId: string,
     resumeFromChunk?: number
   ): Promise<Response> {
-    const redis = new Redis(this.options.redis ?? {});
+    const redis = this.sharedRedis;
     const streamKey = `stream:${runId}:${streamId}`;
     const startChunk = resumeFromChunk ?? 0;
     // Start counting from the resume point, not from 0
     let currentChunkIndex = startChunk;
 
-    const self = this;
-
-    async function cleanup() {
-      try {
-        await redis.quit();
-      } catch (error) {
-        self.logger.error("[RedisRealtimeStreams][ingestData] Error in cleanup:", { error });
-      }
-    }
-
     try {
       const textStream = stream.pipeThrough(new TextDecoderStream());
       const reader = textStream.getReader();
@@ -361,13 +367,11 @@ export class RedisRealtimeStreams implements StreamIngestor, StreamResponder {
       this.logger.error("[RealtimeStreams][ingestData] Error in ingestData:", { error });
 
       return new Response(null, { status: 500 });
-    } finally {
-      await cleanup();
     }
   }
 
   async appendPart(part: string, partId: string, runId: string, streamId: string): Promise<void> {
-    const redis = new Redis(this.options.redis ?? {});
+    const redis = this.sharedRedis;
     const streamKey = `stream:${runId}:${streamId}`;
 
     await redis.xadd(
@@ -386,12 +390,10 @@ export class RedisRealtimeStreams implements StreamIngestor, StreamResponder {
 
     // Set TTL for cleanup when stream is done
     await redis.expire(streamKey, env.REALTIME_STREAM_TTL);
-
-    await redis.quit();
   }
 
   async getLastChunkIndex(runId: string, streamId: string, clientId: string): Promise<number> {
-    const redis = new Redis(this.options.redis ?? {});
+    const redis = this.sharedRedis;
     const streamKey = `stream:${runId}:${streamId}`;
 
     try {
@@ -460,10 +462,6 @@ export class RedisRealtimeStreams implements StreamIngestor, StreamResponder {
       });
       // Return -1 to indicate we don't know what the server has
       return -1;
-    } finally {
-      await redis.quit().catch((err) => {
-        this.logger.error("[RedisRealtimeStreams][getLastChunkIndex] Error in cleanup:", { err });
-      });
     }
   }
 

apps/webapp/app/utils/sse.server.ts

@@ -1,5 +1,6 @@
 import { eventStream } from "remix-utils/sse/server";
 import { env } from "~/env.server";
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
 import { logger } from "~/services/logger.server";
 
 type SseProps = {
@@ -22,6 +23,8 @@ export function sse({ request, pingInterval = 1000, updateInterval = 348, run }:
     return new Response("SSE disabled", { status: 200 });
   }
 
+  const signal = getRequestAbortSignal();
+
   let pinger: NodeJS.Timeout | undefined = undefined;
   let updater: NodeJS.Timeout | undefined = undefined;
   let timeout: NodeJS.Timeout | undefined = undefined;
@@ -32,7 +35,7 @@ export function sse({ request, pingInterval = 1000, updateInterval = 348, run }:
     clearTimeout(timeout);
   };
 
-  return eventStream(request.signal, (send, close) => {
+  return eventStream(signal, (send, close) => {
     const safeSend = (args: { event?: string; data: string }) => {
       try {
         send(args);
@@ -60,15 +63,15 @@ export function sse({ request, pingInterval = 1000, updateInterval = 348, run }:
     };
 
     pinger = setInterval(() => {
-      if (request.signal.aborted) {
+      if (signal.aborted) {
         return abort();
       }
 
       safeSend({ event: "ping", data: new Date().toISOString() });
     }, pingInterval);
 
     updater = setInterval(() => {
-      if (request.signal.aborted) {
+      if (signal.aborted) {
         return abort();
       }
 

apps/webapp/app/utils/sse.ts

@@ -2,6 +2,7 @@ import { type LoaderFunctionArgs } from "@remix-run/node";
 import { type Params } from "@remix-run/router";
 import { eventStream } from "remix-utils/sse/server";
 import { setInterval } from "timers/promises";
+import { getRequestAbortSignal } from "~/services/httpAsyncStorage.server";
 
 export type SendFunction = Parameters<Parameters<typeof eventStream>[1]>[0];
 
@@ -89,15 +90,17 @@ export function createSSELoader(options: SSEOptions) {
       throw new Response("Internal Server Error", { status: 500 });
     });
 
+    const requestAbortSignal = getRequestAbortSignal();
+
     const combinedSignal = AbortSignal.any([
-      request.signal,
+      requestAbortSignal,
       timeoutSignal,
       internalController.signal,
     ]);
 
     log("Start");
 
-    request.signal.addEventListener(
+    requestAbortSignal.addEventListener(
       "abort",
       () => {
         log(`request signal aborted`);