This example app serves as an example of how one can easily instrument HTTP handlers with Prometheus metrics. It uses the Prometheus go client to create a new Prometheus registry.
Usage is simple, on any request to / the request will result in a 200 response code. This increments the counter for this response code. Similarly the /err endpoint will result in a 404 response code, therefore increments that respective counter.
A Docker image is available at: quay.io/brancz/prometheus-example-app:v0.1.0