Expose Health Checks over MP Metrics & vice versa

[derekm]

Exposing Health Checks over MP Metrics would provide recordation, audit & statistics as among the freebie use-cases that are met by such an integration.

On the flip side, deriving Health Checks from existing Metrics would also be beneficial.

Micrometer has a Service Level Objective API that allows building algebraic relationships between existing metrics in order to expose those metrics as new health indicators:

https://github.com/micrometer-metrics/micrometer/blob/master/implementations/micrometer-registry-health/src/main/java/io/micrometer/health/ServiceLevelObjective.java
https://github.com/micrometer-metrics/micrometer/blob/master/implementations/micrometer-registry-health/src/test/java/io/micrometer/health/HealthMeterRegistryTest.java
https://github.com/micrometer-metrics/micrometer/blob/master/implementations/micrometer-registry-health/src/test/java/io/micrometer/health/QueryTest.java

Micrometer's SLO API is fairly simple and straightforward, but one could also imagine using more sophisticated rules engines like clara-rules.org or kie.org in order to support rather sophisticated health indicator rules for observations made through the metrics system.

[xstefank]

I like this idea but I would wait for the metrics specification with micrometer because we cannot depend on micrometer directly.