benchtool: avoid registering DNS metrics twice

[edma2]

Enabling both query and write capabilities (bench.query.enabled, bench.write.enabled) will result in this error on startup:

panic: duplicate metrics collector registration attempted

Use a different metric prefix for query and write runners.

[gotjosh]

Thanks @edma2 for your contribution! The changes LGTM. I think we could add a quick test to bench.go to avoid any further regressions and could you please add a changelog entry?

[edma2]

@gotjosh I'm happy to add a test - but I'm unsure where to start. One idea is to call NewBenchRunner and check it doesn't fail, but looking at the code it might resolve DNS addresses as a side-effect which doesn't seem ideal for a unit test. Can you provide a pointer? Thanks!

[gotjosh]

Ah, you're right. Adding this test doesn't look as simple as I originally thought.

In that case, I'm happy to proceed as is - can you please add a changelog entry? Something like this within cmd/bechtool should do the trick.

e.g.

Changelog
Order should be CHANGE, FEATURE, ENHANCEMENT, and BUGFIX

unreleased/master
[BUGFIX] Lorem ipsum #188

[edma2]

Sure thing, added to CHANGELOG.

[gotjosh]

Thanks!