Working with the Container registry

About the Container registry

Container registry は、Organization または個人アカウント内にコンテナー イメージを格納し、イメージをリポジトリに関連付けることができます。 権限をリポジトリから継承するか、リポジトリとは別に細かい権限を設定するかを選ぶことができます。 パブリック コンテナー イメージに匿名でアクセスすることもできます。

About Container registry support

The Container registry currently supports the following container image formats:

• Docker Image Manifest V2, Schema 2
• Open Container Initiative (OCI) Specifications

When installing or publishing a Docker image, the Container registry supports foreign layers, such as Windows images.

Authenticating to the Container registry

To authenticate to the Container registry (ghcr.io) within a GitHub Actions workflow, use the GITHUB_TOKEN for the best security and experience. お使いのワークフローで personal access token を使用してレジストリの認証を受ける場合、GITHUB_TOKEN を使用するようにワークフローを更新することを強くお勧めします。

personal access token を使ってレジストリの認証を受けるワークフローの更新に関するガイダンスは、「personal access token を使ってレジストリにアクセスするワークフローのアップグレード」を参照してください。

GITHUB_TOKEN の詳細については「ワークフローで認証する」を参照してください。

アクションでレジストリを使用するときのベスト プラクティスについては、「GitHub Actions のセキュリティ強化」を参照してください。

1. Create a new personal access token (classic) with the appropriate scopes for the tasks you want to accomplish. If your organization requires SSO, you must enable SSO for your new token.

   Note: By default, when you select the write:packages scope for your personal access token (classic) in the user interface, the repo scope will also be selected. The repo scope offers unnecessary and broad access, which we recommend you avoid using for GitHub Actions workflows in particular. For more information, see "Security hardening for GitHub Actions." As a workaround, you can select just the write:packages scope for your personal access token (classic) in the user interface with this url: https://github.com/settings/tokens/new?scopes=write:packages.

   • Select the read:packages scope to download container images and read their metadata.
   • Select the write:packages scope to download and upload container images and read and write their metadata.
   • Select the delete:packages scope to delete container images.

   For more information, see "Creating a personal access token for the command line."

2. Save your personal access token (classic). We recommend saving your token as an environment variable.

   $ export CR_PAT=YOUR_TOKEN

3. Using the CLI for your container type, sign in to the Container registry service at ghcr.io.

   $ echo $CR_PAT | docker login ghcr.io -u USERNAME --password-stdin
   > Login Succeeded

Pushing container images

This example pushes the latest version of IMAGE_NAME.

$ docker push ghcr.io/OWNER/IMAGE_NAME:latest

This example pushes the 2.5 version of the image.

$ docker push ghcr.io/OWNER/IMAGE_NAME:2.5

When you first publish a package, the default visibility is private. To change the visibility or set access permissions, see "Configuring a package's access control and visibility."

Pulling container images

Pull by digest

To ensure you're always using the same image, you can specify the exact container image version you want to pull by the digest SHA value.

1. To find the digest SHA value, use docker inspect or docker pull and copy the SHA value after Digest:

   $ docker inspect ghcr.io/OWNER/IMAGE_NAME

2. Remove image locally as needed.

   $ docker rmi  ghcr.io/OWNER/IMAGE_NAME:latest

3. Pull the container image with @YOUR_SHA_VALUE after the image name.

   $ docker pull ghcr.io/OWNER/IMAGE_NAME@sha256:82jf9a84u29hiasldj289498uhois8498hjs29hkuhs

Pull by name

$ docker pull ghcr.io/OWNER/IMAGE_NAME

Pull by name and version

Docker CLI example showing an image pulled by its name and the 1.14.1 version tag:

$ docker pull ghcr.io/OWNER/IMAGE_NAME:1.14.1
  > 5e35bd43cf78: Pull complete
  > 0c48c2209aab: Pull complete
  > fd45dd1aad5a: Pull complete
  > db6eb50c2d36: Pull complete
  > Digest: sha256:ae3b135f133155b3824d8b1f62959ff8a72e9cf9e884d88db7895d8544010d8e
  > Status: Downloaded newer image for ghcr.io/orgname/image-name/release:1.14.1
  > ghcr.io/orgname/image-name/release:1.14.1

Pull by name and latest version

$ docker pull ghcr.io/OWNER/IMAGE_NAME:latest
  > latest: Pulling from user/image-name
  > Digest: sha256:b3d3e366b55f9a54599220198b3db5da8f53592acbbb7dc7e4e9878762fc5344
  > Status: Downloaded newer image for ghcr.io/user/image-name:latest
  > ghcr.io/user/image-name:latest

Building container images

This example builds the hello_docker image:

$ docker build -t hello_docker .

Tagging container images

1. Find the ID for the Docker image you want to tag.

   $ docker images
   > REPOSITORY                                            TAG                 IMAGE ID            CREATED             SIZE
   > ghcr.io/my-org/hello_docker         latest              38f737a91f39        47 hours ago        91.7MB
   > ghcr.io/my-username/hello_docker    latest              38f737a91f39        47 hours ago        91.7MB
   > hello-world                                           latest              fce289e99eb9        16 months ago       1.84kB

2. Tag your Docker image using the image ID and your desired image name and hosting destination.

   $ docker tag 38f737a91f39 ghcr.io/OWNER/NEW_IMAGE_NAME:latest

Labelling container images

Docker ラベルを使用して、説明、ライセンス、ソース リポジトリなどのメタデータをコンテナー イメージに追加できます。 For more information on Docker labels, see LABEL in the official Docker documentation and Pre-Defined Annotation Keys in the opencontainers/image-spec repository.

The following labels are supported in the Container registry. Supported labels will appear on the package page for the image.

Label	Description
org.opencontainers.image.source	The URL of the repository associated with the package. For more information, see "Connecting a repository to a package."
org.opencontainers.image.description	A text-only description limited to 512 characters. This description will appear on the package page, below the name of the package.
org.opencontainers.image.licenses	An SPDX license identifier such as "MIT," limited to 256 characters. The license will appear on the package page, in the "Details" sidebar. For more information, see SPDX License List.

To add labels to an image, we recommend using the LABEL instruction in your Dockerfile. For example, if you're the user monalisa and you own my-repo, and your image is distributed under the terms of the MIT license, you would add the following lines to your Dockerfile:

LABEL org.opencontainers.image.source=https://github.com/monalisa/my-repo
LABEL org.opencontainers.image.description="My container image"
LABEL org.opencontainers.image.licenses=MIT

Alternatively, you can add labels to an image at buildtime with the docker build command.

$ docker build \
 --label "org.opencontainers.image.source=https://github.com/monalisa/my-repo" \
 --label "org.opencontainers.image.description=My container image" \
 --label "org.opencontainers.image.licenses=MIT"