Alert while the value is going beyond the limit

I want to send an alert while I inserting a document with a value more than I configured. Suppose if I configured the KPI as >75 and it crosses it I need a alert.

Sample doc
{ "user" : "Kimanchi", "KPI" : 60 }

Suppose if i inserted the below doc I need an email alert
{ "user" : "Kimanchi", "KPI" : 72 }

For this i saw `elastalert. Is there any pre-build functions are there in elastic-search for these type of requirements???

The Watcher Plugin can do this for you, but do note that it's a commercial plugin. Or you could setup some Percolators which your application monitors and alerts on

Elasticsearch itself does not have any to actually push out alerts via email, pager-duty, etc. You'll need to either use Watcher or code that yourself in your application.

Can you please show any example on how to use percolators in this scenario???

How reabile this elasalert?? http://elastalert.readthedocs.io/en/latest/elastalert.html