Expose metrics to prometheus

[paulfantom]

I believe it would be beneficial to instrument shynet with prometheus metrics as well as expose data collected by shynet in prometheus format. This would provide two benefits:

• with an instrumented application, a monitoring system can act on issues with shynet itself
• exposing data collected by shynet would allow to correlate it with other data in prometheus and create meaningful alerts about website.

I propose prometheus exposition format as there is already an official python library and format is on the path to becoming an RFC standard (under the name of OpenMetrics).

[milesmcc]

Standardizing some kind of remote integration/export format (if I'm understanding this correctly) would be a great addition. Adding it to the roadmap for v1.0.