docs: include required tools in source tree

[cyphar]

In order to be able to build the documentation without internet access
(as is required by some distribution build systems), all of the source
code needed for the build needs to be available in the source tarball.

This used to be possible with the docker-cli sources but was
accidentally broken with some CI changes that switched to downloading
the tools (by modifying go.mod as part of the docs build script).

This pattern also maked documentation builds less reproducible since the
tool version used was not based on the source code version.

Fixes: commit 7dc35c0 ("validate manpages target")
Fixes: commit a650f4d ("switch to cli-docs-tool for yaml docs generation")
Fixes #4212
See #3381
Signed-off-by: Aleksa Sarai asarai@suse.de

[codecov-commenter]

Codecov Report

Merging #4228 (8324502) into master (cd6467b) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

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  Files         288      288           
  Lines       24817    24817           
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  Misses       9113     9113           
  Partials      886      886           

[cyphar]

I'm confused why the doc building validation is failing with Go compilation errors:

go: cannot find main module, but -modfile was set.
	-modfile cannot be used to set the module root directory.

On my machine, with this patch both make manpages and make -f docker.Makefile manpages work without issues. Same goes for yamldocs and mddocs. I'm also using go1.20.3.

[thaJeztah]

It needs a temporary go.mod, otherwise -modfile=vendor.mod won't work.

But we need to look at this change; I know we split these to separate modules to not add the tool's dependencies as dependencies for the main module / vendor, and because we needed these separate modules for our migration to Hugo for the docs website. ./cc @crazy-max @dvdksn

[dvdksn]

I don't think my change had any impact in this respect - it was only moving the doc generation to a subdirectory so it wouldn't confuse Hugo when fetching content files from this repo.

The cli-docs-tool module needs to be an external dep since it's used by other projects as well. I don't suppose there's much harm in vendoring them here -- other than 23k lines of bloat.

[cyphar]

It needs a temporary go.mod, otherwise -modfile=vendor.mod won't work.

Ah. I can add the temporary copying logic for these builds if it's necessary.

I know we split these to separate modules to not add the tool's dependencies as dependencies for the main module / vendor

Unfortunately that's exactly what I'm trying to revert -- removing this from vendoring means that we cannot build Docker's man pages in openSUSE's OBS (there is no internet access in OBS when building packages).

The other alternative would be to include the generated of the man pages in the source tree (verifying they are kept up-to-date in the CI), so distributions can just copy them without needing to use a tool to build them during packaging.

[cyphar]

@thaJeztah I've fixed the go.mod issue, it all works now. 😸

[cyphar]

Rebased.

@thaJeztah Did you want me to go the route of making the documentation be pre-built and then verified in CI? I think packaging things this way is better for distributions (it Just Works ™️ with the distributed tarballs) and the bloat here is only to the tarballs not the final binary, but if it is an issue I can go the other route. Rebasing this patchset for every Docker patch release is getting a little tiring. 😅