Just what it says. When you pull a new passenger, it is stored in the queue until:

Therefore; the queue keeps track of the status of each puller, processor and pusher. It also keeps track of its corresponding log files, which can be viewed on the web interface.

Even after everything is completed, the passenger lingers in the queue for a while. You can determine the wait time per client. Check database section for queue configuration details.

Databus comes with a default queue implementation: databus/pqueue/primal_queue.py . You'll want to use this most of the time.

Implementing a custom queue

Although highly improbable; if, for whatever reason, you need to implement your own queue class; here are the steps necessary.

  • Derive a new class from databus.pqueue.abstract_queue
  • Ensure that your .py file has only one class (which is the queue)
  • Ensure calling super().init()
  • Add the queue class to your client configuration.
    • json_db: /data/json_db/clients/(client name)/config.json
    • sql_db: databus.passenger