Author here. A year ago or so I wrote a similar service called moxy (a reverse proxy for Mesos&#x2F;Marathon entirely in Go) but due to the demand of more advanced features that already existed in nginx I rewrote the whole thing and now its an configuration tool using templates instead. We are using this internally on an average sized production environment, and its been working great so far. Its partly inspired by Bamboo that is a similar tool that configures haproxy, but we preferred nginx for a list of reasons.
Feel free to use, fork, improve, etc!