Hello @all,
(I'm not sure if you guys are interested in a topic like this) I wrote a perl script to gather bandwidth data from my Tor exit relay. The script connects to the Tor control socket, fetches the running config to extract the bandwidth limits and the reject rule count. Afterwards the last 60 bw-cache entries are fetched and average values are built for bandwidth in and out. All this performance data is then forwarded to Nagios/Icinga where you can do anything with that values.
Every 30 minutes a cronjob renders the graph showing the datapoints of the last 6 houres and uploads the resulting image to my website. You can find the image here (Hint: The values for in and out are stacked): https://blog.veloc1ty.de/bandwidth-large.png
The source of the script can be found here on GitHub: https://github.com/vlcty/check_tor_bandwidth It's released under the GPLv3
Maybe somebody will find it usefull :-)
~Josef