Enabling the asset processing queue


In 10.11.0, we introduced a feature to queue the processing of asset derivatives using a simple database queue. The feature is disabled by default. You are able to enable the queue and also configure the background threads that subscribe to the queue.

Enabling the feature

There are two key features that you can enable, assetQueue and assetQueueHeartBeat. The assetQueue feature controls whether or not asset derivative generation will be pushed to the queue, rather than processed inline. The assetQueueHeartBeat feature enables the background thread that will actually process derivative creation. For example, in your Config.cfc:

settings.features.assetQueue.enabled = true;
settings.features.assetQueueHeartBeat.enabled = true; // will not be enabled if assetQueue feature is disabled

Configuring the queue subscriber

You can configure the behaviour of the asset queue "heartbeat" by setting the settings.assetmanager.queue struct:

settings.assetmanager.queue = {
	  concurrency = 8   // number of threads that will concurrenctly run and process the queue (default: 1)
	, batchSize   = 100 // number of assets to be processed by a thread before pausing for ~2 seconds (default: 100)

Multi server environment example

The following example gives an outline of how you could configure a two server setup where one server will be responsible for serving web pages, and the second server will be responsible for processing images. In Config.cfc:

component extends="preside.system.config.Config" {

    public void function configure() {

        // ...
        settings.features.assetQueue.enabled = true;

        environments.prodweb = "mysite.com";
		environments.prodbackend = "backend.mysite.com";


    public void function prodweb() {
    	settings.features.assetQueueHeartBeat.enabled = false;
    public void function prodbackend() {
    	settings.features.assetQueueHeartBeat.enabled = true;
    	settings.features.assetmanager.queue.concurrency = 8;



The above example uses ColdBox environments to achieve the configuration, but other approaches could be used. For example, you could inject environment variables into your application (see Configuring Preside).