This override is used by OpenNext to trigger the revalidation of stale routes. When a stale route is served, OpenNext calls the send method of the queue override to revalidate the route:

• When the route is rendered by the Next server, send is called once the response is sent (in waitUntil when the wrapper provides one).
• With cache interception, send is awaited before the stale response is returned. If it throws, the error is logged and the request falls back to the Next server.

If you want to better understand how to implement your own Queue, the easiest way would be to take a look at the existing included Queue (opens in a new tab).

Couple of things to note :

• The default implementation use an SQS queue. This has the main advantage of being able to control the concurrency of the revalidations as well as avoiding trigerring the revalidation multiple times for the same route.
• The promise returned by send should resolve once the message is accepted (or handed to waitUntil), not once the route is revalidated, so that the response is not delayed.
• You don't have to use a queue at all. You could trigger the revalidation directly in the Queue override itself. You can see a very simple implementation of this in the direct override (opens in a new tab).

Included Queue

sqs

The SQS Queue will send a message to an SQS queue for each route that needs to be revalidated. It is used by default if you don't provide any Queue in your configuration. It uses the @aws-sdk/client-sqs to interact with SQS.

Since @opennextjs/aws 4.1.6, the message is sent in the background when the wrapper provides a waitUntil (i.e. aws-lambda-streaming or aws-apigw-streaming) so that it does not delay the response. Otherwise, the response is sent once the message has been sent. The same applies to sqs-lite.

Requirements

• You need to provide the REVALIDATION_QUEUE_URL environment variable to your server.

sqs-lite

The SQSLite Queue will send a message to an SQS queue for each route that needs to be revalidated. This implementation is a lighter version of the sqs Queue as it uses aws4fetch to interact with SQS.

Requirements

• You need to provide the REVALIDATION_QUEUE_URL, REVALIDATION_QUEUE_REGION(will fallback to us-east-1), AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY and AWS_SESSION_TOKEN environment variables to your server.

direct

The Direct Queue will directly trigger the revalidation of the route in the Queue override itself. It is useful for development purposes and when you don't want to use a queue.

dummy

The Dummy Queue is a dummy implementation that will throw an exception. It should not be used unless you want to disable ISR.