go_get with --arch=linux_x86 fails

[katzdm]

Given a go_get rule in package //third_party/go:

go_get(
    name = "ratelimit",
    get = "gopkg.in/bsm/ratelimit.v1",
)

Running plz build //third_party/go:ratelimit on MacOS will succeed. However, running:

plz build --arch=linux_x86 //third_party/go:ratelimit

will fail. This is because the expected ratelimit.v1.a artifact goes into {TMP_DIR}/pkg/linux_386/gopkg.in/bsm/ratelimit.v1, but plz expects to find the artifact in a linux_x86 directory. Consequently, running the same command with _386 architecture:

plz build --arch=linux_386 //third_party/go:ratelimit

will succeed.

[katzdm]

Hey @peterebden - Thanks for addressing this one! Unfortunately, I believe there is a second, related issue. go_library targets don't seem to find libraries fetched by go_get, when cross-compiling with --arch=linux_x86. More precisely, if I create a target //my_lib to depend on the target from my original issue description, like:

go_library(
    name = "my_lib",
    srcs = ["my_lib.go"],
    deps = ["//third_party/go:ratelimit"],
)

Then this fails with plz build --arch=linux_x86 //my_lib:

Error building target ///linux_x86//my_lib:my_lib: exit status 1
my_lib/my_lib.go, line 9, column 2: can't find import: "gopkg.in/bsm/ratelimit.1/..."

Note that this continues to work, when compiling with --arch=linux_386. I assume this OS -> GOOS change probably needs to be made somewhere else, as well.

[peterebden]

Ah yeah fair - hadn't gotten as far as testing that yet. I think you're probably right (and hopefully it is not hard).

[peterebden]

FWIW f9129b4 should fix that error - but most libraries will fail by missing imports because we don't provide a cross-compiled stdlib for them. Would be nice to do that at some point but it's a bit more work than the fixes here :)

[katzdm]

True, but you provided excellent guidance on http://plz.build for how to work around that, which I've already followed :-)

Go can produce that via something like GOOS="linux" GOARCH="386" go install -i std.

Worked like a charm.

[katzdm]

@peterebden I think you might need to make the OS/GOOS+ARCH/GOARCH change in a few more places in this file - In particular, for the functions _go_library_cmds and _go_binary_cmds. I've tested this change in my local workspace, and it resolves the problem I've been running into - I've opened #591 to fix this.

There are additional uses of CONFIG.OS in go_test and cgo_library, but I'm not as familiar with those rules.

[peterebden]

Ha nice, I should try that for testing I suppose :) Will circle back around to this one when I can!

[katzdm]

This is working now :-)