Use of Metrics in the lower layers

[Cantor, Scott]

> I was planning on trying metrics-spring and metrics-servlets, with the goal of
> running the health check servlet wired via Spring, protected by your new
> admin flow. 

My assumption is the servlets are worthless to us other than as samples to copy into a flow, because they can't be secured as a webflow. I was going to look at copying them or adapting code from them. I doubt there's much there that's very deep.

I hadn't yet decided to spend time on the HealthCheck stuff since we'd have to retrofit some things to fit that.

The Spring stuff I evaluated, but it's a third-party add-on and seems to mostly be targeted at annotation/AutoWiring.

Now, to be fair, if there was something I could see using annotations for, it's this. It's basically AOP, and I think instrumenting is a great fit for that. But we couldn't use it in the OpenSAML layer, and we haven't used annotations with Spring at all, so I wasn't planning to start, or at least not without a discussion.

The other thing the Spring library does have is some custom XML support for wiring up the metrics and reporters, but given that it only supports the built-in reporters, and given that we'll likely need custom ones, it didn't look like it was going to be worth it. I've been playing with native Spring  wiring to get something bootstrapped, but I left off last night before getting fully into testing it.

-- Scott