metlog-raven is a plugin extension for Metlog <http://github.com/mozilla-services/metlog-py>. metlog-raven provides logging extensions to capture stacktraces and some frame information such as local variables to faciliate debugging.
The plugin acts as a thin wrapper around the Raven <https://github.com/dcramer/raven> library for Sentry.
More information about how Mozilla Services is using Metlog (including what is being used for a router and what endpoints are in use / planning to be used) can be found on the relevant spec page.