Update GHA scripts to use bashbrew-buildkit-envs.sh

[tianon]

If our DOI checkout includes the new bashbrew-buildkit-envs.sh script, we should use it to set up our buildkit-related environment variables.

This is a follow-up to docker-library/official-images#14212

[tianon]

Since this is a little bit hard to read this way, here's the raw version of the final prepare string this generates:

git clone --depth 1 https://github.com/docker-library/official-images.git -b master ~/oi
# https://github.com/docker-library/bashbrew/pull/43
export BASHBREW_ARCH=amd64
printf "BASHBREW_ARCH=%q\n" "$BASHBREW_ARCH" >> "$GITHUB_ENV"
if [ -x ~/oi/.bin/bashbrew-buildkit-envs.sh ]; then
	# https://github.com/docker-library/official-images/pull/14212
	buildkitEnvs="$(~/oi/.bin/bashbrew-buildkit-envs.sh)"
	eval "$buildkitEnvs"
	sed <<<"$buildkitEnvs" -re "s/^export[[:space:]]+//" >> "$GITHUB_ENV"
else
	BASHBREW_BUILDKIT_SYNTAX="$(< ~/oi/.bashbrew-buildkit-syntax)"; export BASHBREW_BUILDKIT_SYNTAX
	printf "BASHBREW_BUILDKIT_SYNTAX=%q\n" "$BASHBREW_BUILDKIT_SYNTAX" >> "$GITHUB_ENV"
fi
# create a dummy empty image/layer so we can --filter since= later to get a meaningful image list
{ echo FROM busybox:latest; echo RUN :; } | docker build --no-cache --tag image-list-marker -

[tianon]

LOL now that I have this whole PR written up, I'm realizing the generated scripts never invoke bashbrew build so these won't actually do anything 😂 😭

[codecov-commenter]

Codecov Report

Merging #70 (044742f) into master (296033e) will not change coverage.
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@@           Coverage Diff           @@
##           master      #70   +/-   ##
=======================================
  Coverage   73.10%   73.10%           
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=======================================
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[tianon]

Oh, that's not strictly true -- we do use BASHBREW_BUILDKIT_SYNTAX in our docker buildx build invocation, but setting BUILDX_BUILDER as well will cause breakage because then it will no longer imply --load so our docker run invocations afterwards during the tests will fail. 🙃

I will adjust this to avoid setting BASHBREW_ARCH which should fix this (because then the script will no longer set BUILDX_BUILDER).

[tianon]

I have tested this successfully on a very janky fork of docker-library/rabbitmq by applying the following:

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 70f7d0d..9cbc88e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,11 +19,12 @@ jobs:
       strategy: ${{ steps.generate-jobs.outputs.strategy }}
     steps:
       - uses: actions/checkout@v3
-      - uses: docker-library/bashbrew@HEAD
+      - uses: infosiftr/bashbrew@f98a4a45c7c41911fed1cad0e25c646c7ad06f92 # hack hack hack
       - id: generate-jobs
         name: Generate Jobs
         run: |
           strategy="$("$BASHBREW_SCRIPTS/github-actions/generate.sh")"
+          strategy="$(sed <<<"$strategy" -e 's#docker-library/official-images#infosiftr/stackbrew#g' -e 's/master/bashbrew-buildkit-envs/g')" # hack hack hack
           strategy="$("$BASHBREW_SCRIPTS/github-actions/munge-i386.sh" -c <<<"$strategy")"
           strategy="$(jq -c '.matrix.include |= [ .[] | select(.name | (test("i386") | not) or test("alpine")) ]' <<<"$strategy")" # Ubuntu no longer supports i386 (so we can only build test Alpine there; qemu-user-static is too slow for other arches)
           echo "strategy=$strategy" >> "$GITHUB_OUTPUT"

[tianon]

Updated against the later change to that PR:

git clone --depth 1 https://github.com/docker-library/official-images.git -b master ~/oi
# https://github.com/docker-library/bashbrew/pull/43
if [ -x ~/oi/.bin/bashbrew-buildkit-env-setup.sh ]; then
	# https://github.com/docker-library/official-images/pull/14212
	buildkitEnvs="$(~/oi/.bin/bashbrew-buildkit-env-setup.sh)"
	jq <<<"$buildkitEnvs" -r '
			# this converts from the output of ~/oi/.bin/bashbrew-buildkit-env-setup.sh into what GHA expects in $GITHUB_ENV
			# (in a separate env to make embedding/quoting easier inside this sub-jq)
			to_entries | map(
				(.key | if test("[^a-zA-Z0-9_]+") then
					error("invalid env key: \(.)")
				else . end)
				+ "="
				+ (.value | if test("[\r\n]+") then
					error("invalid env value: \(.)")
				else . end)
			) | join("\n")
		' | tee -a "$GITHUB_ENV"
else
	BASHBREW_BUILDKIT_SYNTAX="$(< ~/oi/.bashbrew-buildkit-syntax)"; export BASHBREW_BUILDKIT_SYNTAX
	printf "BASHBREW_BUILDKIT_SYNTAX=%q\n" "$BASHBREW_BUILDKIT_SYNTAX" >> "$GITHUB_ENV"
fi
# create a dummy empty image/layer so we can --filter since= later to get a meaningful image list
{ echo FROM busybox:latest; echo RUN :; } | docker build --no-cache --tag image-list-marker -

[tianon]

I guess my comments don't really belong inside there... 😞

Fixed in the latest. 👍

[tianon]

Tested with a very hacky fork of rabbitmq again (same patch as above, new commit hash):

+ git clone --depth 1 https://github.com/infosiftr/stackbrew.git -b bashbrew-buildkit-envs /home/runner/oi
Cloning into '/home/runner/oi'...
+ '[' -x /home/runner/oi/.bin/bashbrew-buildkit-env-setup.sh ']'
++ /home/runner/oi/.bin/bashbrew-buildkit-env-setup.sh
+ buildkitEnvs='{"BASHBREW_BUILDKIT_SYNTAX":"docker/dockerfile:1@sha256:39b85bbfa7536a5feceb7372a0817649ecb[27](https://github.com/tianon/hack-hack-hack-rabbitmq/actions/runs/4441998729/jobs/7797766917#step:3:28)24562a38360f4d6a7782a409b14"}'
+ tee -a /home/runner/work/_temp/_runner_file_commands/set_env_6679fb4c-d8f4-418f-abda-4157baa29039
+ jq -r '
			to_entries | map(
				(.key | if test("[^a-zA-Z0-9_]+") then
					error("invalid env key: \(.)")
				else . end)
				+ "="
				+ (.value | if test("[\r\n]+") then
					error("invalid env value: \(.)")
				else . end)
			) | join("\n")
		'
BASHBREW_BUILDKIT_SYNTAX=docker/dockerfile:1@sha256:39b85bbfa7536a5feceb7372a0817649ecb2724562a38360f4d6a7782a409b14
+ echo FROM busybox:latest
+ docker build --no-cache --tag image-list-marker -
+ echo RUN :
Sending build context to Docker daemon  2.048kB

Step 1/2 : FROM busybox:latest
latest: Pulling from library/busybox
1487bff95222: Pulling fs layer
1487bff95222: Verifying Checksum
1487bff95222: Download complete
1487bff95222: Pull complete
Digest: sha256:c118f538365369207c12e5794c3cbfb7b042d950af590ae6c[28](https://github.com/tianon/hack-hack-hack-rabbitmq/actions/runs/4441998729/jobs/7797766917#step:3:29)7ede74f[29](https://github.com/tianon/hack-hack-hack-rabbitmq/actions/runs/4441998729/jobs/7797766917#step:3:30)b7d4
Status: Downloaded newer image for busybox:latest
 ---> bab98d58e29e
Step 2/2 : RUN :
 ---> Running in b1e3dcea67f7
Removing intermediate container b1e3dcea67f7
 ---> 8[33](https://github.com/tianon/hack-hack-hack-rabbitmq/actions/runs/4441998729/jobs/7797766917#step:3:34)ca898b66e
Successfully built 833ca898b66e
Successfully tagged image-list-marker:latest