Overview
GitHub Actions は、ビルド、テスト、デプロイのパイプラインを自動化できる継続的インテグレーションと継続的デリバリー (CI/CD) のプラットフォームです。 You can create workflows that build and test every pull request to your repository, or deploy merged pull requests to production.
GitHub Actions goes beyond just DevOps and lets you run workflows when other events happen in your repository. For example, you can run a workflow to automatically add the appropriate labels whenever someone creates a new issue in your repository.
GitHub provides Linux, Windows, and macOS virtual machines to run your workflows, or you can host your own self-hosted runners in your own data center or cloud infrastructure.
For more information about introducing GitHub Actions to your enterprise, see 企業への GitHub Actions の導入.
The components of GitHub Actions
You can configure a GitHub Actions workflow to be triggered when an event occurs in your repository, such as a pull request being opened or an issue being created. Your workflow contains one or more jobs which can run in sequential order or in parallel. Each job will run inside its own virtual machine runner, or inside a container, and has one or more steps that either run a script that you define or run an action, which is a reusable extension that can simplify your workflow.
Workflows
ワークフローとは、1 つ以上のジョブを実行する構成可能な自動化プロセスです。 ワークフローは、リポジトリにチェックインされる YAML ファイルによって定義され、リポジトリ内のイベントによってトリガーされたときに実行されます。また、手動でトリガーしたり、定義されたスケジュールでトリガーしたりすることもできます。
ワークフローは、リポジトリ内の .github/workflows ディレクトリで定義されます。 1 つのリポジトリで複数のワークフローを使用でき、それぞれで次のような異なるタスクのセットを実行できます。
- Pull request のビルドとテスト
- リリースが作成される度にアプリケーションを配置する
- 新しい issue が開かれる度にラベルを追加する
You can reference a workflow within another workflow. For more information, see ワークフローの再利用.
For more information, see ワークフローの書き込み.
Events
An event is a specific activity in a repository that triggers a workflow run. For example, an activity can originate from GitHub when someone creates a pull request, opens an issue, or pushes a commit to a repository. You can also trigger a workflow to run on a schedule, by posting to a REST API, or manually.
For a complete list of events that can be used to trigger workflows, see Events that trigger workflows.
Jobs
A job is a set of steps in a workflow that is executed on the same runner. Each step is either a shell script that will be executed, or an action that will be run. Steps are executed in order and are dependent on each other. Since each step is executed on the same runner, you can share data from one step to another. For example, you can have a step that builds your application followed by a step that tests the application that was built.
You can configure a job's dependencies with other jobs; by default, jobs have no dependencies and run in parallel. When a job takes a dependency on another job, it waits for the dependent job to complete before running.
For example, you might configure multiple build jobs for different architectures without any job dependencies and a packaging job that depends on those builds. The build jobs run in parallel, and once they complete successfully, the packaging job runs.
For more information, see ワークフロー動作の選択.
Actions
An action is a custom application for the GitHub Actions platform that performs a complex but frequently repeated task. Use an action to help reduce the amount of repetitive code that you write in your workflow files. An action can pull your Git repository from GitHub, set up the correct toolchain for your build environment, or set up the authentication to your cloud provider.
You can write your own actions, or you can find actions to use in your workflows in the GitHub Marketplace.
アクションを公開せずにエンタープライズ全体でアクションを共有するには、内部リポジトリにアクションを格納し、同じ組織またはエンタープライズ内の任意の組織が所有する他のリポジトリ内の GitHub Actions ワークフローへのアクセスを許可するようにリポジトリを構成します。 詳しくは、「アクションとワークフローを企業と共有する」をご覧ください。
For more information on actions, see 自動化の共有.
Runners
A runner is a server that runs your workflows when they're triggered. Each runner can run a single job at a time. GitHub provides Ubuntu Linux, Microsoft Windows, and macOS runners to run your workflows. Each workflow run executes in a fresh, newly-provisioned virtual machine.
GitHub also offers より大きなランナーs, which are available in larger configurations. For more information, see より大きなランナーの使用.
If you need a different operating system or require a specific hardware configuration, you can host your own runners.
For more information about self-hosted runners, see 自分のランナーをホストする.