Backup Report Type alwaysSummarize

[lephisto]

Context

XO Backup Reporting, especially when using slack / Mattermost transport

Current behavior

Currently it's only possible to report "always" and "onFailure". When using "always" with a bigger Backup job like 20+ VM's it exceeds the maximum of 4k Chars you can send to a Mattermost external Webhook (that's why this issue came up). onFailure will only report on failures.

Desired behavior

It would come handy to have something like "alwaysSummarize", if there's just a little Summary like "X/X VM's successfully backed up", to be aware if the backup job is not working at all.

[olivierlambert]

I think we can improve it relatively easily, either by adding a "compact mode" option with less info but just to tell if it works or not, both for "always" and "on failure".

[olivierlambert]

@marcungeschikts we need to find someone to assign on this, no big rush but we should have it in the backlog

[julien-f]

To do first: refactor the plugin to use Handlebar/Markdown templates

[olivierlambert]

@julien-f now the plugin is refactored, so it should be easier and creates a nice highlight for a reasonable cost :)