Add preliminary Go 1.21 support

[eskultety]

This PR just deals with the necessary bits to get projects building with 1.21. Proper 1.21 support including support for the toolchain will be proposed in the future.

Maintainers will complete the following section

• Commit messages are descriptive enough
• Code coverage from testing does not decrease and new code is covered
• Docs updated (if applicable)
• Docs links in the code are still valid (if docs were updated)

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[brunoapimentel]

We need to update the go version in the docs: https://github.com/containerbuildsystem/cachi2/blob/main/README.md?plain=1#L311.

Besides this, LGTM 🚀

[eskultety]

Converting to draft as due to #419 (comment) this should be proposed as POC first.

[eskultety]

Dropping the draft flag, since we can assume the latest revision to act as v1.

Note that unit/integration tests implementation was skipped for v1 (apart from the necessary changes to keep the existing suite passing) to get review on the overall design.

[chmeliik]

Approach LGTM 👍

Didn't go into the details

[brunoapimentel]

So, I'm having a small issue running this locally when I target a Go 1.18 repo:

2024-01-19 11:24:45,216 INFO go.mod recommends/requires Go version: 1.18
2024-01-19 11:24:45,216 INFO Downloading the gomod dependencies
2024-01-19 11:24:49,141 ERROR The command "go install golang.org/dl/go1.20@latest" failed
2024-01-19 11:24:49,141 ERROR STDERR:
go: downloading golang.org/dl v0.0.0-20240109181448-9c0c6b2b4a66
build cache is required, but could not be located: GOCACHE is not defined and neither $XDG_CACHE_HOME nor $HOME are defined

I could work around this by passing my local $HOME to the run_cmd process, so I'm guessing this is needed in local envs?

[eskultety]

So, I'm having a small issue running this locally when I target a Go 1.18 repo:

2024-01-19 11:24:45,216 INFO go.mod recommends/requires Go version: 1.18
2024-01-19 11:24:45,216 INFO Downloading the gomod dependencies
2024-01-19 11:24:49,141 ERROR The command "go install golang.org/dl/go1.20@latest" failed
2024-01-19 11:24:49,141 ERROR STDERR:
go: downloading golang.org/dl v0.0.0-20240109181448-9c0c6b2b4a66
build cache is required, but could not be located: GOCACHE is not defined and neither $XDG_CACHE_HOME nor $HOME are defined

I could work around this by passing my local $HOME to the run_cmd process, so I'm guessing this is needed in local envs?

Doh! I knew about this, but forgot to address it amongst other things that had to be done here. So Go's SDK download and install requires git (which, duh, everyone should have), potentially gcc (but this should be Go's direct dependency). Lastly, Go builds some artifacts (as can be seen in the Containerfile commit which deletes them), so yeah, I'll point Go to some GOCACHE

[brunoapimentel]

One more small detail: apparently, very old versions of go.mod files lack the go {version} line: https://github.com/release-engineering/retrodep/blob/master/go.mod

I think we can easily leave this as unsupported... but maybe it's just as easy to assume this should be handled by go 1.20.

[eskultety]

One more small detail: apparently, very old versions of go.mod files lack the go {version} line: https://github.com/release-engineering/retrodep/blob/master/go.mod

I think we can easily leave this as unsupported... but maybe it's just as easy to assume this should be handled by go 1.20.

LOL, that must be veeery old. Well, my original unposted version of the code handling this situation looked roughly like this:

try:
  run go list -f {{.GoVersion}} -m
except Exception:
 # if go failed to parse go.mod, falback to regex
re.match(...)

But then I figured versions of Go that wouldn't pass parsing with the regex have already been long EOL'd.
I can add the code back if you want, but the error reporting was funky in that case, because we'd have reported "Failed to download dependencies" by the time we get to the fallback code in the except clause, so more work would be needed.

but maybe it's just as easy to assume this should be handled by go 1.20.

Yeah, good point, I can set the parsed version using the regex to a fixed value of the bundled Go if the regex doesn't find a match (so that we get past the version comparisons) and let the bundled Go installation (since it claims to be backwards compatible) handle it, that's a trivial fix.

[eskultety]

since v1:

• Go._retry has now a better description along with more generic error messages since we're running more than just dependency downloading commands
• _get_gomod_version now returns a fixed 1.20 string if a go.mod doesn't specify the go directive (Note however, that this way any newer Go toolchain will modify go.mod with its own version in such case; not a problem of cachi2)
• explicitly set GOCACHE with go install and <gover>/bin/go download to prevent build cache is required, but could not be located: GOCACHE is not defined and neither $XDG_CACHE_HOME nor $HOME are defined error

[brunoapimentel]

Maybe it'd be good to add some unit tests to the new Go class to improve coverage: https://coveralls.io/builds/65216054/source?filename=cachi2%2Fcore%2Fpackage_managers%2Fgomod.py.

I think we also should bump some of our integration test-repos to Go 1.21 (or add new branches/scenarios). But we can do this in a follow up story.

[eskultety]

Maybe it'd be good to add some unit tests to the new Go class to improve coverage: https://coveralls.io/builds/65216054/source?filename=cachi2%2Fcore%2Fpackage_managers%2Fgomod.py.

I think we also should bump some of our integration test-repos to Go 1.21 (or add new branches/scenarios). But we can do this in a follow up story.

Sure, I will add them provided I have a green light on this approach, see #427 (comment)

[eskultety]

since v2:

• rearranged some of the commits slightly
• added unit tests for the Go instance methods
• cosmetic code changes due to the unit tests

[taylormadore]

LGTM 👍

[eskultety]

Since v3:

• minor cosmetic changes

[eskultety]

since v4:

• silence Hadolint

[eskultety]

@taylormadore @ben-alkov please give this one more quick look and if it looks good I'll proceed with the merge.

[taylormadore]

Still LGTM 👍