This is an rsyslog to elasticsearch update proxy for monitoring events.
It receives monitoring events sent from rsyslog in HTTP through omelasticsearch,
then sends updates to elasticsearch.

Goal: hypervisor for monitoring events

+------------------+          +------+         +-------------+
| rsyslog          |          |update|         |elasticsearch|
| omeslasticsearch |   -->    |proxy |   -->   |index        |
+------------------+          +------+         +-------------+

TODO, ideas:
- put events in queues, ZeroMQ, Redis, ...
- queue workers to consume events (scale on several instances)
- alerts confirmation, problem duration
- notifications
- workflow for metrics indexation (ES, InfluxDB, Prometheus, ...)
- metrics based events, watch (Prometheus integration for instance)

Links:
- https://github.com/JustinTulloss/zeromq.node
- https://github.com/NodeRedis/node_redis

Indexation:
- Should we absolutely minimize application joins?
- Query example: i:192.168.1.28 & t:Linux
- IP and type fields should be on a device object only
- https://www.elastic.co/guide/en/elasticsearch/reference/current/parent-join.html
- https://www.elastic.co/guide/en/elasticsearch/reference/current/nested.html
- https://www.rethinkdb.com/