Add minimum Go version detection

[Dean-Coakley]

Fixes: #436

TODO:

• Test

[CLAassistant]

All committers have signed the CLA.

[grcevski]

Hi @Dean-Coakley, thanks for working on this!

I apologize, I should've been more specific. We want to detect that the instrumentable is not of an older Go version. Beyla won't compile without 1.20 I think, so I think we are safe if Beyla's go version is older, the dependencies we use won't allow it to compile.

To check the version of the program we are instrumenting we just need a check here:

https://github.com/grafana/beyla/blob/760d3ad8b21dc880606b0d5d0d60f93c1ed02ba7/pkg/internal/goexec/gofile.go#L15C9-L15C9

	goVersion, modules, err := getGoDetails(elfFile)
	if err != nil {
		return nil, fmt.Errorf("getting Go details: %w", err)
	}

	goVersion = strings.ReplaceAll(goVersion, "go", "")
	log().Debug("Go version detected", "version", goVersion)

At the last line above, we log the Go version we've discovered of the instrumentable. All it's needed is to check if what we found there is older than 1.17 and return the error just like above, where we can't find any go details. This should trickle back all the way and avoid instrumenting the application as a go program. We should also log a debug message saying we found an old version and we won't be instrumenting it using the go uprobes.

Finally, I think we should also call the getGoDetails() function at this line here:

beyla/pkg/internal/goexec/structmembers.go

Line 123 in 760d3ad

return offs, nil

In case we find go symbols in the ELF we wouldn't bother checking for what's the Go version, we trust what the ELF says the offsets are. A simple call with only caring about the returned err should suffice. If we get an error there we can just propagate it upward to make the go instrumentation fail. We may need to refactor things a bit in findLibraryVersions() to ensure we have proper code reuse.

On the tests topic, I think it will be sufficient to add a unit test for the version check, essentially test that we can recognize version older than 1.17, and newer or equal, with the goVersion variable above.

We can also add an integration test with a docker compose of an old Go application, but I can help there once we get to that point.

Again we really appreciate you picking this up, let me know if you'd like to continue with the suggestion I made above.

Cheers.

[Dean-Coakley]

Hi @grcevski

Apologies for misinterpreting the issue.

Still interested in giving this a shot. However it is a lot more work than I initially expected, may take a few weeks for me to get a chance to take a look at this. 😅

[grcevski]

Hi @Dean-Coakley,

Still interested in giving this a shot. However it is a lot more work than I initially expected, may take a few weeks for me to get a chance to take a look at this. 😅

100%, take your time!

[Dean-Coakley]

Seems this is going to be handled by 485.

Closing