0.12.0 requires local_config_cc to be configured

[Toxicable]

Now that rules_docker depends on rules_go we have an issue where downstream users who trying to build a nodejs, or other non C++ containers, now requires C++ to be setup and configured.
The specific error im getting in CI:

ERROR: /home/runner/.cache/bazel/_bazel_runner/f2e96da83c9a9bca36350376aeb4df02/external/io_bazel_rules_go/BUILD.bazel:80:1: Target '@io_bazel_rules_go//:cgo_context_data' depends on toolchain '@local_config_cc//:cc-compiler-k8', which cannot be found: error loading package '@local_config_cc//': Unable to load file '@local_config_cc//:armeabi_cc_toolchain_config.bzl': file doesn't exist'

The defaults work on my workstation but not in CI since I don't know what system deps are required for the C/C++ tool chains to configure themselves on our CI docker container.

I think if possible we should change some config so that downstream projects don't require the C/C++ toolchains to be configured.
or
Provide documentation for how to disable it.
or
If it's not possible to disable this requirement, then provide documentation on how to setup the C/C++ toolchain, even a mention + a link would be suffcient here.

[nlopezgi]

Thanks for creating this issue. I will look into it asap.

[nlopezgi]

see also bazel-contrib/rules_go#2089 (comment)

[nlopezgi]

rules_docker now includes an implementation for containerregistry that is go based. It's very likely the case that this go code has a dependency on a C toolchain that we cannot remove. It's also quite possible that rules_go now always requires this dependency on the C toolchain to be present (@jayconrod, can you comment if you know?).
If this is the case, then a C toolchain is required now to use rules_docker.
Setting up a C/C++ toolchain should be as simple as installing the required packages for Bazel (e.g., https://docs.bazel.build/versions/master/install-ubuntu.html#step-1-install-required-packages). Will keep open to wait for opinion from @jayconrod, but likely, you'll just need to install gcc/clang in your CI (note this is a requirement for Bazel overall to have C/C++ tools installed).

[jayconrod]

@nlopezgi I just commented on bazel-contrib/rules_go#2089 (comment).

+1 to installing gcc or clang as a workaround.

[nlopezgi]

Thanks for your comment. Closing for now as a C/C++ toolchain is stated as a requirement for installing Bazel and it is now a hard requirement for these rules. Please let me know if for any reason anyone wants me to reopen.