Cache Metricset retrieves the JMX key `Catalina:context=*,host=*,name=Cache,type=WebResourceRoot`. It exposes the following metrics:

* `tomcat.cache.mbean`: Mbean that this event is related to.
* `tomcat.cache.hit.total`: The number of requests for resources that were served from the cache.
* `tomcat.cache.size.total.kb`: The current estimate of the cache size in kB
* `tomcat.cache.size.max.kb`: The maximum permitted size of the cache in kB
* `tomcat.cache.lookup.total`: The number of requests for resources
* `tomcat.cache.ttl.ms`: The time-to-live for cache entries in milliseconds
