Exporting Vespa metrics to Prometheus

Specify vespa-configserver (hostname:port) in environment VESPA_CONFIGSERVER

Usage with docker

# docker build -t vespa-exporter .
# docker run -e VESPA_CONFIGSERVER=vespa-configserver.example.com:19071 vespa-exporter

If you are running your vespa container locally, remember to add --network=host to your docker run command.