Prometheus counters should have _total suffix

[raymondlam]

When running the Prometheus' format checker, we found the following warnings:

1. Counters metrics should have "_total" suffix

   Prometheus prefers _total over _count for the suffix.

2. non-histogram and non-summary metrics should not have "_count" suffix

   For Histogram/Timer, the _count should be within the Prometheus summary metric

3. no help text

   To reduce the amount of help texts, we didn't require # Help to be included in every metric line. It might be better to ignore this warning.

[pilhuhn]

Raymond Lam @raymondlam 20:39
@pilhuhn any opinion, on #137, I think the moving the count under the "summary" type for Timer/Histogram is easy enough

Heiko W. Rupp @pilhuhn Sept. 13 20:41
Yes.
(That is 2)
Not sure about 1) and I agree that 3) is overkill

Raymond Lam @raymondlam 20:42
For 1), whether we want to always append _total to Counter is debatable.

Heiko W. Rupp @pilhuhn Sept. 13 20:43
Yes. I think it is overkill

Raymond Lam @raymondlam 20:45
I would prefer that developer facing docs should mention that Prometheus prefers _total at the end for counters but not force it on them by the server

Heiko W. Rupp @pilhuhn Sept. 13 20:46
makes sense

[pilhuhn]

Number 2 was addressed in #142