Google Pub/Sub INVALID_ACK_DEADLINE error encountered when setting the acknowledgment deadline for a subscription.

What is Google Pub/Sub INVALID_ACK_DEADLINE error encountered when setting the acknowledgment deadline for a subscription.

Understanding Google Pub/Sub

Google Cloud Pub/Sub is a messaging service designed to provide reliable, many-to-many, asynchronous messaging between applications. It enables developers to decouple services that produce events from services that process events, allowing for scalable and flexible application architectures.

Identifying the Symptom

When working with Google Pub/Sub, you might encounter the INVALID_ACK_DEADLINE error. This error typically occurs when you attempt to set an acknowledgment deadline for a subscription that is outside the allowed range.

What You Observe

Developers may notice that their applications are failing to acknowledge messages correctly, leading to repeated delivery of the same messages. The error message INVALID_ACK_DEADLINE is logged, indicating an issue with the acknowledgment deadline setting.

Explaining the Issue

The INVALID_ACK_DEADLINE error arises when the acknowledgment deadline for a subscription is set to a value that is not within the permissible range. Google Pub/Sub requires that the acknowledgment deadline be set between 10 seconds and 600 seconds. This deadline determines how long Pub/Sub waits for an acknowledgment before resending the message.

Why It Matters

Setting an appropriate acknowledgment deadline is crucial for ensuring that messages are processed efficiently and not redelivered unnecessarily. An incorrect setting can lead to increased message processing costs and potential message duplication.

Steps to Fix the Issue

To resolve the INVALID_ACK_DEADLINE error, follow these steps to set the acknowledgment deadline within the allowed range:

Step 1: Review Current Settings

First, check the current acknowledgment deadline setting for your subscription. You can do this using the Google Cloud Console or the gcloud command-line tool.

gcloud pubsub subscriptions describe YOUR_SUBSCRIPTION_NAME

Step 2: Update the Ack Deadline

If the current setting is outside the 10 to 600 seconds range, update it using the following command:

gcloud pubsub subscriptions update YOUR_SUBSCRIPTION_NAME --ack-deadline=SECONDS

Replace SECONDS with a value between 10 and 600 that suits your application's needs.

Step 3: Verify the Update

After updating the acknowledgment deadline, verify the change by describing the subscription again:

gcloud pubsub subscriptions describe YOUR_SUBSCRIPTION_NAME

Ensure that the ackDeadlineSeconds field reflects the new value.

Additional Resources

For more information on managing subscriptions and acknowledgment deadlines, refer to the Google Cloud Pub/Sub Subscriber Guide. Additionally, the Pub/Sub API Reference provides detailed information on subscription management.