Reflex is an event handling system for Mesos. It's designed for stream processing workloads built from arbitrary commands communicating over stdio.

An example: reading logs and sinking them to a database.

First, we'll register our handler (called a Task in Reflex):

$ curl reflex.service.consul:4000/1/tasks -X POST -d '{"ID":"log-sinker","subscribesTo":["applicationLogLine"],"image":"TODO/oursampleimage","cpu":0.25,"mem":512}'

Now, whenever an applicationLogLine event comes down the pipe the task is triggered. We can send an event like this:

$ curl reflex.service.consul:4000/1/events -X POST -d '{"type":"applicationLogLine","payload":"this is a log line!"}'

You can do that and see that reflex has created a task in Mesos for that event. Hooray!

As a slightly more complex example, you could register several tasks for different handlers in Reflex, then each task triggers a new event, so that you end up with a pipeline of streams of data that will scale dynamically to the load given it.