commit 25a7797820d045b255436bed47306af71a1d9ed5
author Kevin Lubick <kjlubick@google.com> Thu Jan 13 10:19:38 2022 -0500
committer Kevin Lubick <kjlubick@google.com> Thu Jan 13 15:53:27 2022 +0000
tree bca236c026d5b7a9635703f5076dbcee604a8e98
parent abb611550eb8e8b82949895395a5a6c3e06ae7ab

[bazel] Add mirrors to every external dependency.

- We always download from https
- All external assets have a primary and a mirror URL.
- We prioritize the sources as follows:
    bazel mirror, github/original source, our mirror
- There is a way (see build_toolchain) to test the sources
  from the mirrors (done before CL submission).

This adds a utility to upload files to the mirror in a
consistent, scripted way. It includes a way to copy in
parts of our bazel files (e.g. debs_to_install from
toolchain/build_toolchain.bzl) to update many things
at once.

Our Bazel mirror (gs://skia-world-readable/bazel)
is a Content Addressable Storage system, where the
file name is based on the sha256sum of the contents
(the same hash that Bazel uses). All files in it should
be publicly accessible.

Change-Id: Ida8b8e07d27a0a557bc49467ebbc86c806cabbd3
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/494478
Reviewed-by: Joe Gregorio <jcgregorio@google.com>