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Allowing your codespace to access a private image registry

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You can use secrets to allow Codespaces to access a private image registry

Codespaces is available for organizations using GitHub Team or GitHub Enterprise Cloud. For more information, see "GitHub's products."

About private image registries and Codespaces

A registry is a secure space for storing, managing, and fetching private container images. You may use one to store one or more images. There are many examples of registries, such as GitHub Container Registry, Azure Container Registry, or DockerHub.

GitHub Container Registry can be configured to pull container images seamlessly, without having to provide any authentication credentials to Codespaces. For other image registries, you must create secrets in GitHub to store the access details, which will allow Codespaces to access images stored in that registry.

Accessing images stored in GitHub Container Registry

GitHub Container Registry is the easiest way for GitHub Codespaces to consume devcontainer container images.

For more information, see "Working with the Container registry".

Accessing an image published to the same repository as the codespace

If you publish a container image to GitHub Container Registry in the same repository that the codespace is being launched in, you will automatically be able to fetch that image on codespace creation. You won't have to provide any additional credentials, unless the Inherit access from repo option was unselected when the container image was published.

Inheriting access from the repository from which an image was published

By default, when you publish a container image to GitHub Container Registry, the image inherits the access setting of the repository from which the image was published. For example, if the repository is public, the image is also public. If the repository is private, the image is also private, but is accessible from the repository.

This behavior is controlled by the Inherit access from repo option. Inherit access from repo is selected by default when publishing via GitHub Actions, but not when publishing directly to GitHub Container Registry using a Personal Access Token (PAT).

If the Inherit access from repo option was not selected when the image was published, you can manually add the repository to the published container image's access controls. For more information, see "Configuring a package's access control and visibility."

Accessing an image published to the organization a codespace will be launched in

If you want a container image to be accessible to all codespaces in an organization, we recommend that you publish the container image with internal visibility. This will automatically make the image visible to all codespaces within the organization, unless the repository the codespace is launched from is public.

If the codespace is being launched from a public repository referencing an internal or private image, you must manually allow the public repository access to the internal container image. This prevents the internal image from being accidentally leaked publicly. For more information, see "Ensuring Codespaces access to your package."

Accessing a private container from a subset of repositories in an organization

If you want to allow a subset of an organization's repositories to access a container image, or allow an internal or private image to be accessed from a codespace launched in a public repository, you can manually add repositories to a container image's access settings. For more information, see "Ensuring Codespaces access to your package."

Publishing a container image from a codespace

Seamless access from a codespace to GitHub Container Registry is limited to pulling container images. If you want to publish a container image from inside a codespace, you must use a personal access token (PAT) with the write:packages scope.

We recommend publishing images via GitHub Actions. For more information, see "Publishing Docker images."

Accessing images stored in other container registries

If you are accessing a container image from a registry that isn't GitHub Container Registry, Codespaces checks for the presence of three secrets, which define the server name, username, and personal access token (PAT) for a container registry. If these secrets are found, Codespaces will make the registry available inside your codespace.

  • <*>_CONTAINER_REGISTRY_SERVER
  • <*>_CONTAINER_REGISTRY_USER
  • <*>_CONTAINER_REGISTRY_PASSWORD

You can store secrets at the user, repository, or organization-level, allowing you to share them securely between different codespaces. When you create a set of secrets for a private image registry, you need to replace the "<*>" in the name with a consistent identifier. For more information, see "Managing encrypted secrets for your codespaces" and "Managing encrypted secrets for your repository and organization for Codespaces."

If you are setting the secrets at the user or organization level, make sure to assign those secrets to the repository you'll be creating the codespace in by choosing an access policy from the dropdown list.

Image registry secret example

Example secrets

For a private image registry in Azure, you could create the following secrets:

ACR_CONTAINER_REGISTRY_SERVER = mycompany.azurecr.io
ACR_CONTAINER_REGISTRY_USER = acr-user-here
ACR_CONTAINER_REGISTRY_PASSWORD = <PAT>

For information on common image registries, see "Common image registry servers." Note that accessing AWS Elastic Container Registry (ECR) is different.

Image registry secret example

Once you've added the secrets, you may need to stop and then start the codespace you are in for the new environment variables to be passed into the container. For more information, see "Suspending or stopping a codespace."

Accessing AWS Elastic Container Registry

To access AWS Elastic Container Registry (ECR), you can provide an AWS access key ID and secret key, and GitHub can retrieve an access token for you and log in on your behalf.

*_CONTAINER_REGISTRY_SERVER = <ECR_URL>
*_CONTAINER_REGISTRY_USER = <AWS_ACCESS_KEY_ID>
*_CONTAINER_REGISTRY_PASSWORD = <AWS_SECRET_KEY>

You must also ensure you have the appropriate AWS IAM permissions to perform the credential swap (e.g. sts:GetServiceBearerToken) as well as the ECR read operation (either AmazonEC2ContainerRegistryFullAccess or ReadOnlyAccess).

Alternatively, if you don't want GitHub to perform the credential swap on your behalf, you can provide an authorization token fetched via AWS's APIs or CLI.

*_CONTAINER_REGISTRY_SERVER = <ECR_URL>
*_CONTAINER_REGISTRY_USER = AWS
*_CONTAINER_REGISTRY_PASSWORD = <TOKEN>

Since these tokens are short lived and need to be refreshed periodically, we recommend providing an access key ID and secret.

While these secrets can have any name, so long as the *_CONTAINER_REGISTRY_SERVER is an ECR URL, we recommend using ECR_CONTAINER_REGISTRY_* unless you are dealing with multiple ECR registries.

For more information, see AWS ECR's "Private registry authentication documentation."

Common image registry servers

Some of the common image registry servers are listed below:

Debugging private image registry access

If you are having trouble pulling an image from a private image registry, make sure you are able to run docker login -u <user> -p <password> <server>, using the values of the secrets defined above. If login fails, ensure that the login credentials are valid and that you have the apprioriate permissions on the server to fetch a container image. If login succeeds, make sure that these values are copied appropriately into the right Codespaces secrets, either at the user, repository, or organization level and try again.