fix: realtime streams from tasks now retry if they receive a 408 timeout error from the realtime/trigger.dev server (#1952)

Author: ericallam

.changeset/hip-cups-wave.md

@@ -0,0 +1,5 @@
+---
+"@trigger.dev/sdk": patch
+---
+
+Fix issue where realtime streams would cut off after 5 minutes

packages/core/src/v3/runMetadata/metadataStream.ts

@@ -1,3 +1,7 @@
+import { request as httpsRequest } from "node:https";
+import { request as httpRequest } from "node:http";
+import { URL } from "node:url";
+
 export type MetadataOptions<T> = {
   baseUrl: string;
   runId: string;
@@ -7,57 +11,140 @@ export type MetadataOptions<T> = {
   signal?: AbortSignal;
   version?: "v1" | "v2";
   target?: "self" | "parent" | "root";
+  maxRetries?: number;
 };
 
 export class MetadataStream<T> {
   private controller = new AbortController();
   private serverStream: ReadableStream<T>;
   private consumerStream: ReadableStream<T>;
-  private streamPromise: Promise<void | Response>;
+  private streamPromise: Promise<void>;
+  private retryCount = 0;
+  private readonly maxRetries: number;
+  private currentChunkIndex = 0;
+  private reader: ReadableStreamDefaultReader<T>;
 
   constructor(private options: MetadataOptions<T>) {
     const [serverStream, consumerStream] = this.createTeeStreams();
     this.serverStream = serverStream;
     this.consumerStream = consumerStream;
+    this.maxRetries = options.maxRetries ?? 10;
+    this.reader = this.serverStream.getReader();
 
     this.streamPromise = this.initializeServerStream();
   }
 
   private createTeeStreams() {
     const readableSource = new ReadableStream<T>({
       start: async (controller) => {
-        for await (const value of this.options.source) {
-          controller.enqueue(value);
+        try {
+          for await (const value of this.options.source) {
+            controller.enqueue(value);
+          }
+          controller.close();
+        } catch (error) {
+          controller.error(error);
         }
-
-        controller.close();
       },
     });
 
     return readableSource.tee();
   }
 
-  private initializeServerStream(): Promise<Response> {
-    const serverStream = this.serverStream.pipeThrough(
-      new TransformStream<T, string>({
-        async transform(chunk, controller) {
-          controller.enqueue(JSON.stringify(chunk) + "\n");
+  private async makeRequest(startFromChunk: number = 0): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const url = new URL(this.buildUrl());
+      const timeout = 15 * 60 * 1000; // 15 minutes
+
+      const requestFn = url.protocol === "https:" ? httpsRequest : httpRequest;
+      const req = requestFn({
+        method: "POST",
+        hostname: url.hostname,
+        port: url.port || (url.protocol === "https:" ? 443 : 80),
+        path: url.pathname + url.search,
+        headers: {
+          ...this.options.headers,
+          "Content-Type": "application/json",
+          "X-Resume-From-Chunk": startFromChunk.toString(),
         },
-      })
-    );
-
-    return fetch(this.buildUrl(), {
-      method: "POST",
-      headers: this.options.headers ?? {},
-      body: serverStream,
-      signal: this.controller.signal,
-      // @ts-expect-error
-      duplex: "half",
+        timeout,
+      });
+
+      req.on("error", (error) => {
+        reject(error);
+      });
+
+      req.on("timeout", () => {
+        req.destroy(new Error("Request timed out"));
+      });
+
+      req.on("response", (res) => {
+        if (res.statusCode === 408) {
+          if (this.retryCount < this.maxRetries) {
+            this.retryCount++;
+
+            resolve(this.makeRequest(this.currentChunkIndex));
+            return;
+          }
+          reject(new Error(`Max retries (${this.maxRetries}) exceeded after timeout`));
+          return;
+        }
+
+        if (res.statusCode && (res.statusCode < 200 || res.statusCode >= 300)) {
+          const error = new Error(`HTTP error! status: ${res.statusCode}`);
+          reject(error);
+          return;
+        }
+
+        res.on("end", () => {
+          resolve();
+        });
+
+        res.resume();
+      });
+
+      if (this.options.signal) {
+        this.options.signal.addEventListener("abort", () => {
+          req.destroy(new Error("Request aborted"));
+        });
+      }
+
+      const processStream = async () => {
+        try {
+          while (true) {
+            const { done, value } = await this.reader.read();
+
+            if (done) {
+              req.end();
+              break;
+            }
+
+            const stringified = JSON.stringify(value) + "\n";
+            req.write(stringified);
+            this.currentChunkIndex++;
+          }
+        } catch (error) {
+          req.destroy(error as Error);
+        }
+      };
+
+      processStream().catch((error) => {
+        reject(error);
+      });
     });
   }
 
+  private async initializeServerStream(): Promise<void> {
+    try {
+      await this.makeRequest(0);
+    } catch (error) {
+      this.reader.releaseLock();
+      throw error;
+    }
+  }
+
   public async wait(): Promise<void> {
-    return this.streamPromise.then(() => void 0);
+    return this.streamPromise;
   }
 
   public [Symbol.asyncIterator]() {