use watermark settings to determine warning/critical disk space level indicator color

[lmenezes]

as reported on lmenezes/elasticsearch-kopf#351

[Fabian1976]

Any progress on this?

[breml]

Hi @lmenezes

Thanks for your wonderful tool to monitor Elasticsearch clusters. We happily use it for years now and it has always been very helpful and without any problems.

Over time the attached storage on our nodes increased more and more and it was no longer feasible to use the default watermark settings, because this led to unreasonable high absolute values for the disk space kept as free reserve by Elasticsearch.

Citing @TheCase in lmenezes/elasticsearch-kopf#351

if the watermarks differ from default, use the watermark settings to determine warning (low, yellow) and critical (high, red) color for disk space indicator graphic under node in cluster view.

It appears that you are currently using a hard-coded low default of 75% to trigger the change from green to red.

This is exactly what we are looking for. Do you see any chance of working on this?

I would offer my help to work on a PR for this, but unfortunately I am of no help with neither Scala nor Javascript.