I've just deployed ELK in an attempt to see if it can be used for monitoring logs and alerting about issues.
What I need to be able to detect is mostly missing records: Say a log record was received, saying a user is about to make some sort of request. I then expect to see the log record saying the request has been made.
If the second record was not received within X seconds from the arrival of the first, then something is wrong, and I want to alert about it.
Any ideas how to achieve that?