graphite-project/carbon — pull request #32 by slackhappy (2012-08-29 23:26:31+00:00)
Title: add aggregated-consistent-hashing relay rule

This change adds a new type of relay rule which determines the appropriate destination for a metric by first applying the aggregation rules specified in aggregation-rules.conf, then applying consistent hashing on any resulting aggregated metric paths (or the original, if nothing matches).

The change is designed to address this type of problem:
https://answers.launchpad.net/graphite/+question/187874

But, without having to hand-convert the aggregation-rules into evenly distributed relay rules. With this change, pointing the relay at the aggregation-rules.

I have tested that this also works for non-aggregated metrics, which will pass through the aggregator.

Here is a sample topology that would be enabled:
![Sample Topologyt](http://f.cl.ly/items/0Y0I1G1z1D402q3n0h42/Screen%20shot%202012-08-29%20at%207.18.41%20PM.png)

To use, in the [relay] section, set
RELAY_METHOD = aggregated-consistent-hashing