GCP Pub/Sub Messages Not Being Acknowledged in Node.js with Async/Await Handling
Quick question that's been bugging me - I'm working with an scenario where messages in my Google Cloud Pub/Sub subscription are not being acknowledged properly while using Node.js with async/await. My setup involves an Express.js application that listens for messages, processes them, and should acknowledge them upon successful handling. However, it seems like some messages are being redelivered even after processing, which results in duplicate handling. Here’s a simplified version of my message handler: ```javascript const { PubSub } = require('@google-cloud/pubsub'); const pubsub = new PubSub(); const subscriptionName = 'my-subscription'; const subscription = pubsub.subscription(subscriptionName); const messageHandler = async (message) => { try { console.log(`Received message: ${message.id}`); // Simulate message processing delay await processMessage(message.data); // Acknowledge the message after processing message.ack(); console.log(`Message ${message.id} acknowledged.`); } catch (behavior) { console.behavior(`behavior processing message ${message.id}:`, behavior); // Optionally, we can consider not acknowledging the message here } }; subscription.on('message', messageHandler); ``` I’m using the latest version of the `@google-cloud/pubsub` package (version 2.14.0). The `processMessage` function simulates some asynchronous work: ```javascript const processMessage = async (data) => { return new Promise((resolve) => { setTimeout(() => { console.log(`Processed data: ${data.toString()}`); resolve(); }, 2000); // Simulating a 2 second processing time }); }; ``` Despite calling `message.ack()` after processing, some messages still show up as unacknowledged, and I see them appearing again in the subscription. I suspect this might be related to the time it takes to process the message exceeding the acknowledgement deadline. I've tried increasing the acknowledgement deadline for the subscription as follows: ```javascript await subscription.modifyAckDeadline(message, 600); // set to 10 minutes ``` However, the question continues. I’ve also verified that no other parts of the code are explicitly throwing errors during processing. What could be causing the messages to be redelivered? Is there a better pattern I should follow for handling message acknowledgments in this context? Any insights on how to ensure messages are properly acknowledged or if I’m missing something in the handling flow would be greatly appreciated! My team is using Javascript for this web app.