feat(release): automate release archive and publish on GitHub Actions

.bcr/README.md

@@ -0,0 +1,9 @@
+# Bazel Central Registry
+
+When the ruleset is released, we want it to be published to the
+Bazel Central Registry automatically:
+<https://registry.bazel.build>
+
+This folder contains configuration files to automate the publish step.
+See <https://github.com/bazel-contrib/publish-to-bcr/blob/main/templates/README.md>
+for authoritative documentation about these files.

.bcr/config.yml

@@ -0,0 +1,5 @@
+# See https://github.com/bazel-contrib/publish-to-bcr#a-note-on-release-automation
+
+fixedReleaser:
+  login: alexeagle
+  email: [email protected]

.bcr/metadata.template.json

@@ -0,0 +1,17 @@
+{
+  "homepage": "https://github.com/bazelbuild/rules_license",
+  "maintainers": [
+    {
+      "github": "aiuto",
+      "name": "Tony Aiuto"
+    },
+    {
+      "email": "[email protected]",
+      "github": "alexeagle",
+      "name": "Alex Eagle"
+    }
+  ],
+  "repository": ["github:bazelbuild/rules_license"],
+  "versions": [],
+  "yanked_versions": {}
+}

.bcr/presubmit.yml

@@ -0,0 +1,13 @@
+matrix:
+  platform:
+    - centos7
+    - debian10
+    - ubuntu2004
+    - macos
+    - windows
+tasks:
+  verify_targets:
+    name: Verify build targets
+    platform: ${{ platform }}
+    build_targets:
+      - "@rules_license//tests/..."

.bcr/source.template.json

@@ -0,0 +1,5 @@
+{
+  "integrity": "**leave this alone**",
+  "strip_prefix": "{REPO}-{VERSION}",
+  "url": "https://github.com/{OWNER}/{REPO}/releases/download/{TAG}/rules_license-{TAG}.tar.gz"
+}

.github/workflows/release.yml

@@ -0,0 +1,16 @@
+# Automatically perform a release whenever a new "release-like" tag is pushed to the repo.
+name: Release
+
+on:
+  push:
+    tags:
+      # Detect tags that look like a release.
+      # Note that we don't use a "v" prefix to help anchor this pattern.
+      # This is purely a matter of preference.
+      - "*.*.*"
+
+jobs:
+  release:
+    uses: bazel-contrib/.github/.github/workflows/release_ruleset.yaml@v5
+    with:
+      release_files: rules_license-*.tar.gz

.github/workflows/release_prep.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+
+set -o errexit -o nounset -o pipefail
+
+# Set by GH actions, see
+# https://docs.github.com/en/actions/learn-github-actions/environment-variables#default-environment-variables
+readonly TAG=${GITHUB_REF_NAME}
+# The prefix is chosen to match what GitHub generates for source archives.
+# This guarantees that users can easily switch from a released artifact to a source archive
+# with minimal differences in their code (e.g. strip_prefix remains the same)
+readonly PREFIX="rules_license-${TAG}"
+readonly ARCHIVE="rules_license-$TAG.tar.gz"
+
+# Configuration for 'git archive'
+# see https://git-scm.com/docs/git-archive/2.40.0#ATTRIBUTES
+cat >.git/info/attributes <<EOF
+# Omit folders that users don't need, making the distribution artifact smaller
+examples export-ignore
+
+# Substitution for the _VERSION placeholder in version.bzl
+version.bzl export-subst
+EOF
+
+git archive --format=tar --prefix=${PREFIX}/ ${TAG} | gzip > $ARCHIVE
+SHA=$(shasum -a 256 $ARCHIVE | awk '{print $1}')
+
+# The stdout of this program will be used as the top of the release notes for this release.
+cat << EOF
+## Using bzlmod with Bazel 6 or later:
+
+1. Add \`common --enable_bzlmod\` to \`.bazelrc\`.
+
+2. Add to your \`MODULE.bazel\` file:
+
+\`\`\`starlark
+bazel_dep(name = "rules_license", version = "${TAG}")
+\`\`\`
+
+## Using WORKSPACE:
+
+\`\`\`starlark
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "rules_license",
+    sha256 = "${SHA}",
+    strip_prefix = "${PREFIX}",
+    url = "https://github.com/bazelbuild/rules_license/releases/download/${TAG}/${ARCHIVE}",
+)
+\`\`\`starlark
+EOF

MODULE.bazel

@@ -1,6 +1,7 @@
 module(
     name = "rules_license",
-    version = "0.0.7",  # Keep in sync with version.bzl
+    # Note: the publish-to-BCR app will patch this line to stamp the version being published.
+    version = "0.0.0",
     compatibility_level = 1,
 )
 

docs/CONTRIBUTING.md

@@ -31,3 +31,13 @@ implementation.
 
 This project follows
 [Google's Open Source Community Guidelines](https://opensource.google/conduct/).
+
+## Releasing
+
+To perform a release, simply tag the commit you wish to release, for example:
+
+```
+rules_license$ git fetch
+rules_license$ git tag 1.2.3 origin/main
+rules_license$ git push origin 1.2.3
+```

version.bzl

@@ -13,4 +13,9 @@
 # limitations under the License.
 """The version of rules_license."""
 
-version = "0.0.7"
+# This is automagically replace by git during git archive using `git export-subst`
+# See https://git-scm.com/docs/git-archive/2.29.0#Documentation/git-archive.txt-export-subst
+_VERSION_PRIVATE = "$Format:%(describe:tags=true)$"
+
+# When using rules_license from source rather than from a release artifact, export a placeholder value
+version = "0.0.0-unreleased" if _VERSION_PRIVATE.startswith("$Format") else _VERSION_PRIVATE