debug: add version constraint to avoid pprof panic

[davemay99]

This PR introduces go-version constraint checks to avoid capturing the threadcreate pprof profile on Nomad versions 0.11.0 to 0.11.2. The code to obtain the version number for a given server or node ID isn't pretty, but in lieu of a better method it should suffice for now.

Fixes #12804.

[tgross]

Thanks for the PR @davemay99. The code here is roughly correct (although I've left some comments), but I have a concern about this approach in a more general sense:

We're trying to rip out all the backcompat code that supports unsupported versions of Nomad (ex #12791). So I'm honestly not convinced we should do this at all, especially given that this version of Nomad is vulnerable to being crashed by anyone hitting the threadcreate pprof endpoint, as I noted in #12804 (comment).

If we are going to do it, I think this approach is too narrow: I'd propose we skip the entire pprof on any version of Nomad earlier than 0.12.0 (that's when we switched to go modules and at least have a reasonable story for discovering what's going on with dependencies).

I pushed changes myself

[tgross]

@lgfa29 @davemay99 in the interest of moving things along, I've pushed updates for my comments onto this PR, along with the changelog entry and rebased on main (the branch was pretty old). But now I shouldn't be the one to 👍 the PR so I'm adding @schmichael to the reviewers so that either @lgfa29 or @schmichael can get to it first 😀

[davemay99]

If we are going to do it, I think this approach is too narrow: I'd propose we skip the entire pprof on any version of Nomad earlier than 0.12.0 (that's when we switched to go modules and at least have a reasonable story for discovering what's going on with dependencies).

This PR was driven by a specific scenario and is the only incompatibility that I am aware of. The remainder of the pprofs work as expected and still provide valuable debugging context for all versions of Nomad.

@tgross Are you open to the following 2 changes? I would be happy to provide the commit.

1. revert the version constraint back to ">= 0.11.0, <= 0.11.2"
2. only skip the threadcreate pprof

[jazzyfresh]

made some feedback comments but can ignore

[jazzyfresh]

Suggested change

	return fmt.Errorf("unsupported version=%s matches version filter %s", version, minimumVersionPprofConstraint)
	return fmt.Errorf("unsupported version=%s matches version filter %s", version, versionConstraint)

should show the versionConstraint passed in since it used for checking

[github-actions]

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