Create Release GitHub Action for Bazel Workspaces Using bzlrelease

This repository contains a GitHub Action that creates a release for Bazel workspaces which use cgrindel/bazel-starlib/bzlrelease.

The action will do the following:

1. Creates a release tag with the latest commit on your main branch.
2. Generates release notes by calling //release:generate_release_notes using the workspace snippet generated by //release:generate_workspace_snippet.
3. Creates a release using the generated release notes and the release tag.
4. Updates the README.md file with the release's workspace snippet.
5. Creates a PR with the README.md update and configures it to auto-merge.

(This assumes that the release targets were defined under //release.)

Table of Contents

• Quickstart
  • Implement bzlrelease in your Bazel workspace
  • Set Up a GitHub App to Generate Tokens
  • Implement a GitHub Actions Workflow for Creating a Release
  • Create a release

Quickstart

The following provides a brief introduction to setting up a release process using bzlrelease and the action in this repository.

Implement bzlrelease in your Bazel workspace

See bzlrelease for more details.

For this quickstart, we will assume that you implemented your release targets in a Bazel package located at //release. The BUILD.bazel file should look something like the following:

load(
    "@cgrindel_bazel_starlib//bzlrelease:defs.bzl",
    "create_release",
    "generate_release_notes",
    "generate_workspace_snippet",
    "update_readme",
)

# MARK: - Release

generate_workspace_snippet(
    name = "generate_workspace_snippet",
    template = "workspace_snippet.tmpl",
)

generate_release_notes(
    name = "generate_release_notes",
    generate_workspace_snippet = ":generate_workspace_snippet",
)

update_readme(
    name = "update_readme",
    generate_workspace_snippet = ":generate_workspace_snippet",
)

create_release(
    name = "create",
    workflow_name = "Create Release",
)

Set Up a GitHub App to Generate Tokens

The default Github token that is provided to the workflow does not have permission to create releases and PRs. This article from peter-evans/create-pull-request explains how to create a GitHub application to generate tokens with the appropriate permissions. When you have created the token generator application, you need to create two secrets in your repository. The first is named APP_ID. It's value is the App ID: XXXX value (e.g., XXXX) found on the token generator application's About page. The second secret is named APP_PRIVATE_KEY. It's value is the private key that you generated while creating the token generator application.

Implement a GitHub Actions Workflow for Creating a Release

In your repository, create a file at .github/workflows/create_release.yml with the following contents:

name: Create Release

on:
  workflow_dispatch:
    inputs:
      release_tag:
        required: true
        type: string
      reset_tag:
        type: boolean
        default: false
      base_branch:
        description: The branch being merged to.
        type: string
        default: main

jobs:
  create_release:
    runs-on: ubuntu-latest
    env:
      CC: clang

    steps:

    # Check out your code
    - uses: actions/checkout@v2

    # Generate a token that has permssions to create a release and create PRs.
    - uses: tibdex/github-app-token@v1
      id: generate_token
      with:
        app_id: ${{ secrets.APP_ID }}
        private_key: ${{ secrets.APP_PRIVATE_KEY }}

    # Configure the git user for the repository
    - uses: cgrindel/gha_configure_git_user@v1

    # Create the release
    - uses: cgrindel/gha_create_release@v1
      with:
        release_tag: ${{  github.event.inputs.release_tag }}
        reset_tag: ${{  github.event.inputs.reset_tag }}
        base_branch: ${{  github.event.inputs.base_branch }}
        github_token: ${{ steps.generate_token.outputs.token }}

Commit this file and merge to your main branch.

Create a release

After merging the create_release.yml workflow to your main branch, you can create a release by running the following inside your repository:

# Create a release with the tag v1.2.3
$ bazel run //release:create -- v1.2.3

This utility will launch the create_release.yml workflow in GitHub Actions.