Knowing whether a single user-agent was responsible for load spikes would be helpful for diagnostics and incident response, as well as long-term growth planning.
Given that we have the 4 parallel connection per IP in place and difficulties of implementing this. I propose we decline this ticket. We need some better protections against malicious DDoS though but I doubt this would help.
My two cents: given the big cardinality of user-agent header I think doing this with grafana (and thus graphite or prometheus) would be impractical. Kibana/Elasticsearch should have no problem displaying something like this though.
FWIW, I 'll echo @Ladsgroup and @fgiunchedi. Having the data is obviously useful. Representing them in grafana on the other hand it probably not so practical. I also have my doubts as to whether a graph would help identify the culprits of load spikes, mostly due to the nature of the service, but I am be at fault here.