ci: Mitigate network issues in native Windows job

hebasto commented at 3:30 pm on April 7, 2026: member

This PR mitigates network issues when vcpkg downloads source tarballs by caching the entire vcpkg/downloads directory.

Closes #34996.

Note for Maintainers: To properly populate the new CI cache, all current vcpkg binary caches must be cleared to trigger a rebuild.

hebasto added the label Windows on Apr 7, 2026

hebasto added the label Tests on Apr 7, 2026

DrahtBot commented at 3:30 pm on April 7, 2026: contributor

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hebasto commented at 4:43 pm on April 7, 2026: member

The size of windows-native-dll-vcpkg-downloads is about 1.2 GB, compared to 470 MB for windows-native-dll-vcpkg-tools.

Perhaps we could exclude vcpkg/downloads/tools from the cache.

hebasto marked this as a draft on Apr 7, 2026

hebasto force-pushed on Apr 7, 2026

hebasto commented at 9:23 pm on April 7, 2026: member

Perhaps we could exclude vcpkg/downloads/tools from the cache.

Done.

The size of windows-native-dll-vcpkg-downloads is about 1.2 GB…

It’s 800 MB now.

maflcko commented at 6:11 am on April 8, 2026: member

Can you explain why the tools were previously cached, what they are, and why it is fine to no longer cache them?

hebasto commented at 7:53 am on April 8, 2026: member

Can you explain why the tools were previously cached…

To skip downloading and unpacking them whenever possible.

… what they are…

They are Windows binaries used for building packages for the target triplet. Here are the contents of the vcpkg/downloads/tools directory from the CI:

 0$ ls -l ~/AppData/Local/vcpkg/downloads/tools
 1total 164
 2drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:37 jom
 3drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:46 meson-1.8.2-3d2461
 4drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:49 msys2
 5drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:37 nasm
 6drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:29 ninja
 7drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:37 perl
 8drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:29 powershell-core-7.5.4-windows
 9drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:46 python
10drwxr-xr-x 1 runneradmin 197121 0 Apr  7 14:46 win_bison

… and why it is fine to no longer cache them?

It is a tradeoff. The downloaded tool archives are now cached along with the package source tarballs. However, vcpkg has to unpack them on every run.

in .github/workflows/ci.yml:262 in cd8092df88 outdated

262-          path: ~/AppData/Local/vcpkg/downloads/tools
263-          key: ${{ github.job }}-vcpkg-tools-${{ github.run_id }}
264-          restore-keys: ${{ github.job }}-vcpkg-tools-
265+          path: |
266+            ~/AppData/Local/vcpkg/downloads/*
267+            !~/AppData/Local/vcpkg/downloads/tools

maflcko commented at 8:43 am on April 8, 2026:

Is there a need to set a path on a download? Wouldn’t it be easier to just set the correct path on upload only?

hebasto commented at 2:35 pm on April 9, 2026:

Yes, there is a need. The path input participates in cache entity identification. Therefore, a pair of actions/cache/restore and actions/cache/save must have the exact same path configured, or it will result in a cache miss.

in .github/workflows/ci.yml:290 in cd8092df88

291         with:
292-          path: ~/AppData/Local/vcpkg/downloads/tools
293-          key: ${{ github.job }}-vcpkg-tools-${{ github.run_id }}
294+          path: |
295+            ~/AppData/Local/vcpkg/downloads/*
296+            !~/AppData/Local/vcpkg/downloads/tools

maflcko commented at 8:45 am on April 8, 2026:

0            !~/AppData/Local/vcpkg/downloads/tools  # Cache the tools once as archives, but not redundantly in extracted form.

nit: Maybe add a comment here, as per my question and your answer?

hebasto commented at 2:28 pm on April 9, 2026:

Thanks! The comment has been added.

ci, refactor: Reuse primary key in `actions/cache/save`

This avoids code duplication and improves readability.

88bbf2ad33

ci: Cache `vcpkg/downloads` folder in native Windows CI job

The new cache is keyed with the hash of 'vcpkg.json', which reduces
cache storage consumption compared to keying by run ID.

The `vcpkg/downloads/tools` subdirectory is excluded to further save
space.

dc93091083

hebasto force-pushed on Apr 9, 2026

hebasto marked this as ready for review on Apr 9, 2026

hebasto commented at 2:36 pm on April 9, 2026: member

The feedback from @maflcko has been addressed.

ci: Mitigate network issues in native Windows job #35024

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