coding-guy

https://github.com/Seldaek/monolog/blob/master/src/Monolog/Handler/ElasticSearchHandler.php
https://github.com/Seldaek/monolog/blob/master/src/Monolog/Formatter/ElasticaFormatter.php
https://github.com/Seldaek/monolog/blob/master/src/Monolog/Formatter/LogstashFormatter.php

Another example:
https://github.com/nulpunkt/monolog-elasticsearch-logstashformat