slider develop branch now has basic codahale metrics support

[Steve Loughran <st...@hortonworks.com>]

I've checked in enough of SLIDER-319 for codahale metrics support to be
available for code that chooses to publish stuff, where stuff can be

-meters, gauges, timers and histograms:
https://dropwizard.github.io/metrics/3.1.0/manual/core/
-health checks:
https://dropwizard.github.io/metrics/3.1.0/manual/healthchecks/

if you want to see these at work, bring up an instance then look at
/system/metrics
/system/health
...the links are off the main web page

the most useful is /system/threads : it gives you a thread dump.


The metrics can all be served up via ganglia or JMX; I haven't tried these.

I'm going to add some basic publishing of application state, especially
some live values (failures, requests), and set it up so that a provider can
publish stats too.

Ideally we should consider serving up all machine-level data this way. I'm
thinking of maybe grabbing the metrics data at the end of test runs and
including it in the output. In theory we could even extract the data and
make assertions about it

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