Helix Swarm uses background processes, called workers, to respond to events in the Helix server. The default number of workers is 3, and each worker processes events for up to 10 minutes. When a worker terminates, a new one is spawned.


Each worker maintains a connection to the Helix server for the duration of its lifetime. This may impact your Helix server management practices.

Worker status

To determine the current status of workers, visit the URL: https://myswarm.url/queue/status

The response is formatted in JSON, and looks like this:


During normal use of Swarm, the following error message appears for logged-in users when Swarm detects that no workers are running:

Worker configuration

To adjust the configuration for workers, add a configuration block to the SWARM_ROOT/data/config.php file:

// this block should be a peer of 'p4'
'queue' => array(
'workers' => 3, // defaults to 3
'worker_lifetime' => 595, // defaults to 10 minutes (less 5 seconds)
'worker_task_timeout' => 1800, // defaults to 30 minutes
'worker_memory_limit' => '1G', // defaults to 1 gigabyte


Manually start workers

To kick off a new worker process, visit the URL: https://myswarm.url/queue/worker

When the number of workers running matches the configured limit, the requested worker process is not started.


This technique does start a worker, but it lasts only for its configured lifetime. Typically, you would always want at least one worker running. See Set up a recurring task to spawn workers for details.

Manually restart workers

To restart an idle worker process, remove its lock file:

rm data/queue/workers/worker_id

A worker process that is busy processing a task will continue operation until its task is complete. Immediately afterwards, if the worker notices that its lock file is missing it exits.

If you have a recurring task to start workers, the recurring task starts a fresh worker, if necessary. See Set up a recurring task to spawn workers for details.