Repository and image names

Artifact Registry uses a naming convention to identify repositories and images when you use the API, gcloud, and docker commands to interact with repositories.

Docker repositories

The full name for a docker repository is in the following format:

LOCATION-docker.pkg.dev/PROJECT-ID/REPOSITORY

where:

  • LOCATION is the regional or multi-regional location of the repository.

  • PROJECT is your Google Cloud console project ID. If your project ID contains a colon (:) and you are working with a Docker repository, see Domain-scoped projects.

  • REPOSITORY is the name of the repository.

For example, consider an image with the following characteristics:

  • Repository location: us
  • Repository format: docker
  • Repository name: my-repo
  • Project ID: my-project

The repository is specified as:

us-docker.pkg.dev/my-project/my-repo

Container image names

The full name for a container image is one of the following formats: 

LOCATION-docker.pkg.dev/PROJECT-ID/REPOSITORY/IMAGE

or

LOCATION-docker.pkg.dev/PROJECT-ID/REPOSITORY/IMAGE:TAG

or

LOCATION-docker.pkg.dev/PROJECT-ID/REPOSITORY/IMAGE@IMAGE-DIGEST

where:

  • LOCATION is the regional or multi-regional location of the repository.
  • PROJECT is your Google Cloud console project ID. If your project ID contains a colon (:), see Domain-scoped projects.
  • REPOSITORY is the name of the repository where the image is stored.
  • IMAGE is the name of the image in the repository.
  • TAG is the tag for the image version that you want to pull.

  • IMAGE-DIGEST is the sha256 hash value of the image contents. In Google Cloud console, click the specific image to see its metadata. The digest is listed as the Image digest.

    If you don't specify a tag or a digest, Artifact Registry looks for the image with the default tag latest. See Container image versions for information about versions.

For example, consider an image with the following characteristics:

  • Repository location: us
  • Repository name: my-repo
  • Project ID: my-project
  • Image name: test
  • Tag: staging

This version of the image tagged with staging is specified as:

us-docker.pkg.dev/my-project/my-repo/test:staging

Container image versions

A repository can contain many container images, and these images can have different versions. To identify a specific version of an image, you can specify the image digest or tag.

Digest
An image digest is an automatically generated hash of the image index or image manifest. Each image digest is a unique identifier for an image version and cannot be changed. The digest is the sha256 hash value of the image contents.
Tag

An image tag is a label and is often a human-readable string such as v1.1 or development. A tag can only point to only one version of an image. In Artifact Registry, you can configure a Docker repository to allow mutable image tags or enforce immutable image tags.

  • Mutable: A tag points to only one version of an image, but the specific digest that it references can change.

    A common approach is to tag images with a version identifier, such as v1.1 at build time. When the build pushes multiple versions of the image to the registry with the same v1.1 tag, the tag references the digest of the last version pushed to the registry. Although mutable image tags provide a convenient way to label versions, they can also be manipulated by a bad actor to associate a tag with a malicious version of an image.

  • Immutable: In the repository, a tag always points to the same image digest. If an Artifact Registry repository is configured for immutable image tags, the following actions are not permitted:

    • Delete a tagged image. Deleting untagged images is still permitted.
    • Remove a tag from an image.
    • Push an image with a tag that is already used by another version of the image in the repository.

For example, consider an image with the following characteristics:

  • Repository location: us
  • Repository name: my-repo
  • Project ID: my-project
  • Image name: test
  • Tag: staging
  • Digest: sha256:4d11e24ba8a615cc85a535daa17b47d3c0219f7eeb2b8208896704ad7f88ae2d

To identify the image with the tag, append :staging to the image name:

us-docker.pkg.dev/my-project/my-repo/test:staging

To identify it with the digest, append @ to the image name, followed by the digest:

us-docker.pkg.dev/my-project/my-repo/test@sha256:4d11e24ba8a615cc85a535daa17b47d3c0219f7eeb2b8208896704ad7f88ae2d

If your project ID contains a colon (:), see Domain-scoped projects.

In the console, on the Images screen, the Tags column lists the image's tags. Click the version of the image to see metadata, including the Image digest.

See Tagging Images for more information about tagging.

Domain-scoped projects

If your project is scoped to your domain, the project ID includes the name of the domain followed by a colon (:). Because of how Docker treats colons, you must replace the colon character with a forward slash when you specify an image digest in Artifact Registry. Identify images in these types of projects using the following format:

LOCATION-docker.pkg.dev/DOMAIN/PROJECT-ID/REPOSITORY/IMAGE@IMAGE-DIGEST

For example, the project with ID example.com:my-project could have the following image:

us-docker.pkg.dev/example.com/my-project/my-repo/image-name

Repository names as URLs

To access a repository or artifact in a repository in Google Cloud console, prepend https:// to its full name.

For example, to view the repository us-maven.pkg.dev/my-project/my-repo, use the following URL:

https://us-maven.pkg.dev/my-project/my-repo

To view the image us-docker.pkg.dev/example.com/my-project/my-repo/my-image, use the following URL:

https://us-docker.pkg.dev/example.com/my-project/my-repo/my-image

Any authenticated user who has permission to access the repository can use these links.