hack/buildkit-ref

#!/usr/bin/env bash
# This script returns the current BuildKit ref and source repository being used.
# This script will only work with a BuildKit repository hosted on GitHub.
#
# The output of this script may be valid shell script, but is intended for use with
# GitHub Actions' $GITHUB_ENV.

set -euo pipefail

buildkit_pkg=github.com/moby/buildkit

resolve_github_commit_sha() {
	local repo=$1
	local ref=$2
	local resolved

	if command -v gh > /dev/null 2>&1; then
		if resolved=$(gh api "repos/${repo}/commits/${ref}" --jq '.sha // empty' 2> /dev/null) && [[ -n "$resolved" ]]; then
			echo "$resolved"
			return 0
		fi
	fi

	local curl_args=(-fsSL)
	if [[ -n "${GH_TOKEN:-}" ]]; then
		curl_args+=(-H "Authorization: Bearer ${GH_TOKEN}")
	fi

	if resolved=$(curl "${curl_args[@]}" "https://api.github.com/repos/${repo}/commits/${ref}" | jq -er '.sha // empty'); then
		echo "$resolved"
		return 0
	fi

	return 1
}

# BUILDKIT_REPO and BUILDKIT_REF may be set to override the values from go.mod.
if [ -n "${BUILDKIT_REPO:-}" ]; then
	echo "WARNING: BUILDKIT_REPO is set; overriding BuildKit repository from go.mod with ${BUILDKIT_REPO}" >&2
fi
if [ -n "${BUILDKIT_REF:-}" ]; then
	echo "WARNING: BUILDKIT_REF is set; overriding BuildKit ref from go.mod with ${BUILDKIT_REF}" >&2
fi

# get BuildKit version and repository from go.mod, unless explicitly overridden.
buildkit_ref=${BUILDKIT_REF:-$(go list -mod=mod -u -m -f '{{if .Replace}}{{.Replace.Version}}{{else}}{{.Version}}{{end}}' "$buildkit_pkg")}
buildkit_repo=${BUILDKIT_REPO:-$(go list -mod=mod -u -m -f '{{if .Replace}}{{.Replace.Path}}{{else}}{{.Path}}{{end}}' "$buildkit_pkg")}
buildkit_repo=${buildkit_repo#github.com/}

if [[ "${buildkit_ref}" == *-*-* ]]; then
	# if pseudo-version, figure out just the commit sha
	commit_ref=$(awk -F"-" '{print $NF}' <<< "$buildkit_ref")
	# resolve through GitHub to get the full sha for use as a ref.
	if ! buildkit_ref=$(resolve_github_commit_sha "$buildkit_repo" "$commit_ref"); then
		echo "failed to resolve BuildKit commit ${buildkit_repo}@${commit_ref}" >&2
		exit 1
	fi
fi

cat << EOF
BUILDKIT_REPO=$buildkit_repo
BUILDKIT_REF=$buildkit_ref
EOF