Archelon uses the Rails "Action Cable" functionality to provide dynamic updates to the GUI.
Action Cable runs "in app", so a separate stand-alone Action Cable server is not required.
The application listens for WebSocket requests on the default "/cable" endpoint.
By default, Archelon will use the delayed_job queue adapter in all environments.
Action Cable messages are used for both export and import jobs, so in the following "jobs" refers to both types.
When running jobs, the status of the jobs is updated dynamically using the Rails "Action Cable" functionality. Action Cable enables the browser to receive messages from the server containing data about job status. Browser-side JavaScript is then used to update the relevant portion of the page, so that the status information is displayed to the user without having to perform a page reload.
Note: The following is developer-level information about how the export/import job dynamic update is implemented. It is not necessary to understand this information to perform exports or imports through the GUI.
For each job in a state other than "complete", the ActionCable client on the jobs' index page creates a subscription to that job. A subscription is only created if the authenticated user is either the creator of the job, or if they are an admin.
Status updates to the channels consist of a JSON object with the following attributes:
job- a JSON-serialized representation of the ImportJob or ExportJob objectstatusWidget- HTML representing the status to display for the job
The browser-side JavaScript uses the id in the "job" field to locate the appropriate DOM element using the "data-job-id" HTML attribute, and replaces the HTML of the element with the "statusWidget" content.