Hi Stephen!
We have a rest API that you can use to pull metrics. Easiest way to get the metric path is to go to your Controller -> (Select your Application under "Applications") -> Metric Browser (left menu)
Select the metric(s) you want and right click on it and you should get a "copy REST Url". That should do the trick to grab the metric information you require..
If you are running this from a script you will probably need to authenticate wit HTTP which is described here..https://docs.appdynamics.com/display/PRO44/Using+the+Controller+APIs#UsingtheControllerAPIs-Authentication
-Kevin
... View more