Work out a better way to populate the adaptor list

[josephjclark]

The Workblow builder has a drop-down that lets you pick an adaptor version

At the moment, as I understand it, the list of available adaptors is only update when the server first starts.

It is a pain when releasing a new adaptor version requires a manual Lightning restart. This problem will only get worse with the pre-release stuff.

We need a faster and easier means of updating the list so that it stays more relevant.

Brainstorming some ideas:

• Set a cron job to refresh the list (hourly?)
• Refresh the list every time the drop-down is opened (likely too slow?)
• Use a locally cached list but refresh in the background and show a little spinner while fetching
• Set an automation hook in adaptors which pings lightning on every release and asks it to update (won't help other deployments)
• Maintain a list of adaptor versions as a simple JSON file in some central repo, update that registry on release, and always fetch the registry in lightning

[josephjclark]

My preferred approach would be to:

• Start loading the list when the drop-down is first clicked (probably 90% of loads will never even need the list)
• Show a throbber while the list is loading
• Cache the result (probably in browser storage so it works across pages)
• Next time the list is opened, show the cache immediately but also re-fetch in the background, and show the loading throbber while doing it.

This does require a rich custom picklist component

[josephjclark]

A really easy brute force approach would be to simply popuate the list when the page first loads. Load it in the background and by the time the users clicks the drop-down, it'll be ready for them. It's not THAT much work computationally, and we could consider a server-side cache of the raw data with a short lease (like 5 minutes)