Disk space alert from ElasticSearch or Logstash

I need to trigger a mail whenever logstash or elastic server is about to hit 95% of the disk space. Like i would like to trigger mail when the usage is almost 85%. Is this possible.

If you are using metricbeats, it monitors system filesystems by default. You would just have to create a watch for your configuration.

Here are sample fields from the metricbeat index