GitHub and Buildpack Registry release automation (#787)

* GitHub and Buildpack Registry release automation

This script creates a GitHub release and publishes it to Buildpack Registry, with a bunch of sanity checks.

Prevents the possibility of e.g. typos in between these two steps.

GUS-W-18151411

* Print buildpack registry publish command for reference in case it fails (so a user may re-attempt)

Author: dzuelke

support/util/release.sh

@@ -0,0 +1,80 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+shopt -s inherit_errexit
+
+buildpack_registry_name="heroku/php"
+github_repository_shorthand="heroku/heroku-buildpack-php"
+
+function abort() {
+	echo >&2
+	echo >&2 "Error: ${1}"
+	exit 1
+}
+
+echo >&2 "Checking environment..."
+
+if ! command -v gh >/dev/null; then
+	abort "Install the GitHub CLI first: https://cli.github.com"
+fi
+
+if ! heroku buildpacks:publish --help >/dev/null; then
+	abort "Install the Buildpack Registry plugin first: https://github.com/heroku/plugin-buildpack-registry"
+fi
+
+echo >&2
+echo >&2 "GitHub CLI user info for active account:"
+if ! gh auth status --active; then
+	abort "Log into the GitHub CLI first: gh auth login"
+fi
+
+echo >&2
+echo >&2 "Heroku CLI user info for active account:"
+# Explicitly check the CLI is logged in, since the Buildpack Registry plugin doesn't handle re-authing
+# expired logins properly, which can otherwise lead to the release aborting partway through.
+if ! heroku whoami; then
+	abort "Log into the Heroku CLI first: heroku login"
+fi
+
+if [[ $(gh repo view --json "owner,name" --jq '(.owner.login +"/"+ .name)') != "$github_repository_shorthand" ]]; then
+	abort "Local Git repository remote 'origin' is not ${github_repository_shorthand}"
+fi
+
+echo >&2
+echo >&2 "Fetching releases from GitHub..."
+current_github_release_version=$(gh release view --json tagName --jq '.tagName' | tr -d 'v')
+new_version="$((current_github_release_version + 1))"
+new_git_tag="v${new_version}"
+
+echo "Current release Git tag is v${current_github_release_version}, new tag will be ${new_git_tag}"
+
+echo >&2 "Extracting changelog entry for this release..."
+git fetch origin
+# Using `git show` to avoid having to disrupt the current branch/working directory.
+changelog_entry="$(git show origin/main:CHANGELOG.md | awk "/^## \[v${new_version}\]/{flag=1; next} /^## /{flag=0} flag")"
+
+if [[ -n "${changelog_entry}" ]]; then
+	echo -e "${changelog_entry}\n"
+else
+	abort "Unable to find changelog entry for v${new_version}. Has the prepare release PR been triggered/merged?"
+fi
+
+read -r -p "Release on GitHub as tag '${new_git_tag}' and publish to Buildpack Registry buildpack '${buildpack_registry_name}' [y/n]? " choice
+case "${choice}" in
+	y | Y) ;;
+	n | N) exit 0 ;;
+	*) exit 1 ;;
+esac
+
+echo >&2
+echo >&2 "Creating GitHub release and tag '${new_git_tag}'..."
+gh release create "${new_git_tag}" --title "${new_git_tag}" --notes "${changelog_entry}"
+
+echo >&2
+echo >&2 "Publishing buildpack '${buildpack_registry_name}' using Git tag '${new_git_tag}' on Heroku Buildpack Registry..."
+heroku buildpacks:publish "${buildpack_registry_name}" "${new_git_tag}" || abort "Failed to publish to Buildpack Registry.
+See error message above for details.
+Publishing can be re-attempted using the following command:
+heroku buildpacks:publish ${buildpack_registry_name@Q} ${new_git_tag@Q}"
+echo >&2
+heroku buildpacks:versions "${buildpack_registry_name}" | head -n 3