proposed ADR: use the prometheus metric types

[pritikin]

3/18 meeting notes

consistent with openMetrics as well:
ref: https://prometheus.io/docs/concepts/metric_types/

exposing the measures allows for trending on the measures. for simplicity thats a bit of a stretch goal. these are mostly "count"

the type field goes on the metric as well (in the future. not necessary for now). these are mostly a "gauge"

if everything is a gauge do we need to say anything about it?

Are there other, perhaps ratified ISO etc, standards that we should reach to instead?

[apannetrat]

I looked at the ISO 19086 standard and it qualifies metrics in terms of scale:

• interval scale: continuous scale or discrete scale with equal-sized scale values and an arbitrary zero.
• nominal scale: scale with unordered labeled categories or ordered by convention
• ordinal scale: scale with ordered labeled categories
• ratio scale: continuous scale with equal-sized scale values and an absolute or natural zero point

I don't know if this is useful.