Overview
You can use pre-written building blocks, called actions, in your workflow. An action is a pre-defined, reusable set of jobs or code that perform specific tasks within a workflow.
Actions can be:
- Reusable: actions can be used across different workflows and repositories, allowing you to avoid rewriting the same code.
- Pre-written: many actions are available in the GitHub Marketplace, covering a wide range of tasks like checking out code, setting up environments, running tests, and deploying applications.
- Configurable: you can configure actions with inputs, outputs, and environment variables to tailor them to your specific needs.
- Community-driven: you can create your own actions and share them with others or use actions developed by the community.
The actions you use in your workflow can be defined in:
- The same repository as your workflow file
- Any public repository
- A published Docker container image on Docker Hub
GitHub Marketplace is a central location for you to find actions created by the GitHub community. GitHub Marketplace page enables you to filter for actions by category.
Browsing Marketplace actions in the workflow editor
You can search and browse actions directly in your repository's workflow editor. From the sidebar, you can search for a specific action, view featured actions, and browse featured categories. You can also view the number of stars an action has received from the GitHub community.
- In your repository, browse to the workflow file you want to edit.
- In the upper right corner of the file view, to open the workflow editor, click .
- To the right of the editor, use the GitHub Marketplace sidebar to browse actions. Actions with the badge indicate GitHub has verified the creator of the action as a partner organization.
Adding an action to your workflow
You can add an action to your workflow by referencing the action in your workflow file.
You can view the actions referenced in your GitHub Actions workflows as dependencies in the dependency graph of the repository containing your workflows. For more information, see “About the dependency graph.”
注: セキュリティを強化するため、GitHub Actions はアクションや再利用可能なワークフローのリダイレクトをサポートしません。 つまり、所有者、アクションのリポジトリの名前、またはアクションの名前が変更されると、そのアクションを以前の名前で使用するすべてのワークフローは失敗します。
Adding an action from GitHub Marketplace
An action's listing page includes the action's version and the workflow syntax required to use the action. To keep your workflow stable even when updates are made to an action, you can reference the version of the action to use by specifying the Git or Docker tag number in your workflow file.
- Navigate to the action you want to use in your workflow.
- Click to view the full marketplace listing for the action.
- Under "Installation", click to copy the workflow syntax.
- Paste the syntax as a new step in your workflow. For more information, see "GitHub Actions のワークフロー構文."
- If the action requires you to provide inputs, set them in your workflow. For information on inputs an action might require, see "Using pre-written building blocks in your workflow."
ワークフローに追加したアクションに対してDependabot version updatesを有効化することもできます。 詳しくは、「Dependabot でアクションを最新に保つ」を参照してください。
Adding an action from the same repository
If an action is defined in the same repository where your workflow file uses the action, you can reference the action with either the {owner}/{repo}@{ref}
or ./path/to/dir
syntax in your workflow file.
リポジトリ ファイル構造の例:
|-- hello-world (repository)
| |__ .github
| └── workflows
| └── my-first-workflow.yml
| └── actions
| |__ hello-world-action
| └── action.yml
パスはデフォルトの作業ディレクトリ (github.workspace
、$GITHUB_WORKSPACE
) に対する相対パス (./
) です。 アクションがワークフローとは異なる場所にリポジトリをチェックアウトする場合は、ローカル アクションに使用される相対パスを更新する必要があります。
ワークフロー ファイルの例:
jobs:
my_first_job:
runs-on: ubuntu-latest
steps:
# This step checks out a copy of your repository.
- name: My first step - check out repository
uses: actions/checkout@v4
# This step references the directory that contains the action.
- name: Use local hello-world-action
uses: ./.github/actions/hello-world-action
The action.yml
file is used to provide metadata for the action. Learn about the content of this file in "GitHub Actions のメタデータ構文."
Adding an action from a different repository
If an action is defined in a different repository than your workflow file, you can reference the action with the {owner}/{repo}@{ref}
syntax in your workflow file.
The action must be stored in a public repository.
jobs:
my_first_job:
steps:
- name: My first step
uses: actions/setup-node@v4
Referencing a container on Docker Hub
If an action is defined in a published Docker container image on Docker Hub, you must reference the action with the docker://{image}:{tag}
syntax in your workflow file. To protect your code and data, we strongly recommend you verify the integrity of the Docker container image from Docker Hub before using it in your workflow.
jobs:
my_first_job:
steps:
- name: My first step
uses: docker://alpine:3.8
For some examples of Docker actions, see the Docker-image.yml workflow and "Docker コンテナーのアクションを作成する."
Security hardening for using actions in your workflows
GitHubは、ワークフローのセキュリティを強化するために使用できるセキュリティ機能が用意されています。 GitHubのビルトイン機能を使用し、実行するアクションの脆弱性に関する通知を受け取ったり、ワークフロー内のアクションを最新の状態に保つプロセスを自動化したりできます。 詳しくは、「GitHub のセキュリティ機能を使用して GitHub Actions の使用をセキュリティで保護する」を参照してください。
Using release management for your custom actions
The creators of a community action have the option to use tags, branches, or SHA values to manage releases of the action. Similar to any dependency, you should indicate the version of the action you'd like to use based on your comfort with automatically accepting updates to the action.
You will designate the version of the action in your workflow file. Check the action's documentation for information on their approach to release management, and to see which tag, branch, or SHA value to use.
Note: We recommend that you use a SHA value when using third-party actions. However, it's important to note Dependabot will only create Dependabot alerts for vulnerable GitHub Actions that use semantic versioning. For more information, see "GitHub Actions のセキュリティ強化" and "Dependabot アラートについて."
Using tags
Tags are useful for letting you decide when to switch between major and minor versions, but these are more ephemeral and can be moved or deleted by the maintainer. This example demonstrates how to target an action that's been tagged as v1.0.1
:
steps:
- uses: actions/javascript-action@v1.0.1
Using SHAs
If you need more reliable versioning, you should use the SHA value associated with the version of the action. SHAs are immutable and therefore more reliable than tags or branches. However, this approach means you will not automatically receive updates for an action, including important bug fixes and security updates. You must use a commit's full SHA value, and not an abbreviated value. SHA を選択するときは、アクションのリポジトリからであり、リポジトリ フォークではないことを確認してください。 This example targets an action's SHA:
steps:
- uses: actions/javascript-action@a824008085750b8e136effc585c3cd6082bd575f
Using branches
Specifying a target branch for the action means it will always run the version currently on that branch. This approach can create problems if an update to the branch includes breaking changes. This example targets a branch named @main
:
steps:
- uses: actions/javascript-action@main
For more information, see "カスタム アクションについて."
Using inputs and outputs with an action
An action often accepts or requires inputs and generates outputs that you can use. For example, an action might require you to specify a path to a file, the name of a label, or other data it will use as part of the action processing.
To see the inputs and outputs of an action, check the action.yml
or action.yaml
in the root directory of the repository.
In this example action.yml
, the inputs
keyword defines a required input called file-path
, and includes a default value that will be used if none is specified. The outputs
keyword defines an output called results-file
, which tells you where to locate the results.
name: "Example"
description: "Receives file and generates output"
inputs:
file-path: # id of input
description: "Path to test script"
required: true
default: "test-file.js"
outputs:
results-file: # id of output
description: "Path to results file"
Next steps
To continue learning about GitHub Actions, see "GitHub Actions を理解する."