add(metrics): Track mempool actions and size bucketed by weight

[str4d]

Motivation

It is useful to have insight into the composition of the mempool along the axes used for the default block construction algorithm. The algorithm from the now-deployed ZIP 317 takes into account both a transaction's weight, and the number of "unpaid actions" it contains.

Solution

This PR adds the following new metrics:

• (gauge) zcash.mempool.actions.unpaid { "bk" = ["< 0.2", "< 0.4", "< 0.6", "< 0.8", "< 1"] }
• (gauge) zcash.mempool.actions.paid
• (gauge) zcash.mempool.size.weighted { "bk" = ["< 1", "1", "> 1", "> 2", "> 3"] }

These are proposed as common Zcash metrics (with a zcash. prefix). The corresponding zcashd PR is zcash/zcash#6632.

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[str4d]

zcash/zcash#6632 updates our default Grafana dashboard to use these new metrics. This PR can either be tested against that dashboard, or those changes could be pulled into the zebrad default dashboard as appropriate.

[upbqdn]

Thank you, str4d. I noticed some tests needed adjustments. I fixed them right away.

I can't think of a suitable way to import the dashboards from zcashd. I guess other engineers will know.

[str4d]

Thank you, str4d. I noticed some tests needed adjustments. I fixed them right away.

Ahh, I checked with cargo check --tests locally before pushing, but didn't check cargo check --tests --all-features. Thanks!

I can't think of a suitable way to import the dashboards from zcashd. I guess other engineers will know.

The zcashd dashboard should mostly Just Work, as I think it's mostly relying on metrics that zebrad also has. As for importing that specific part into zebrad's Grafana dashboard, that can be done with some JSON munging, but it might be easier to just create the new panels inside Grafana matching what I did for the zcashd one.

[upbqdn]

This test https://github.com/str4d/zebra/blob/c697558b79d81a3236b3c56261292a48dd3370f6/zebrad/src/components/mempool/storage/tests/prop.rs#L113 panics here https://github.com/str4d/zebra/blob/c697558b79d81a3236b3c56261292a48dd3370f6/zebrad/src/components/mempool/storage/verified_set.rs#L312. Likely because Arbitrary sets unpaid_actions greater than conventional_actions, and proptest sniffs it out. The additions at https://github.com/str4d/zebra/blob/c697558b79d81a3236b3c56261292a48dd3370f6/zebrad/src/components/mempool/storage/verified_set.rs#L325 and below will probably also panic.

[upbqdn]

I opened #6976 to handle the dashboards. I think we can merge this PR first and add the dashboards later, adjusting the code if there are issues.

[teor2345]

Due to #4529, we'll need to push this branch to the zebra repository to get all our CI to run on it.

[mpguerra]

Due to #4529, we'll need to push this branch to the zebra repository to get all our CI to run on it.

Done in #7019

[mergify]

⚠️ The sha of the head commit of this PR conflicts with #7019. Mergify cannot evaluate rules on this PR. ⚠️