The prebuilds that you configure for a repository are created and updated using a GitHub Actions workflow, managed by the Codespaces service.
Depending on the settings in a prebuild configuration, the workflow to update the prebuild template may be triggered by these events:
- Creating or updating the prebuild configuration
- Pushing a commit or a pull request to a branch that's configured to have prebuilds
- Changing any of the dev container configuration files
- A schedule that you've defined in the prebuild configuration
- Manually triggering the workflow
The settings in the prebuild configuration determine which events automatically trigger an update of the prebuild template. For more information, see "Configuring prebuilds."
People with admin access to a repository can check the progress of prebuilds, edit, and delete prebuild configurations.
You can view the current status of the latest workflow run for each prebuild configuration you've set up on the Codespaces page of your repository settings. For example, "Currently running" or "Last run 1 hour ago."
To see the log output for the latest prebuild workflow run, click See output.
This displays the output of the most recent run of the workflow in the Actions tab.
Alternatively, to view all prebuild workflow runs associated with the specified branch, click the ellipsis button and choose View runs from the dropdown menu.
This displays the workflow run history for prebuilds for the associated branch.
On the Codespaces page of your repository settings, click the ellipsis to the right of the prebuild configuration you want to edit.
In the dropdown menu, click Edit.
Make the required changes to the prebuild configuration, then click Update.
To pause the update of prebuild templates for a configuration, you can disable workflow runs for the configuration. Disabling the workflow runs for a prebuild configuration does not delete any previously created prebuild templates for that configuration and, as a result, codespaces will continue to be generated from an existing prebuild template.
Disabling the workflow runs for a prebuild configuration is useful if you need to investigate template creation failures.
On the Codespaces page of your repository settings, click the ellipsis to the right of the prebuild configuration you want to disable.
In the dropdown menu, click Disable runs.
To confirm that you want to disable this configuration, click OK.
Deleting a prebuild configuration also deletes all previously created prebuild templates for that configuration. As a result, shortly after you delete a configuration, prebuilds generated by that configuration will no longer be available when you create a new codespace.
After you delete a prebuild configuration, workflow runs for that configuration that have been queued or started will still run. They will be listed in the workflow run history, along with previously completed workflow runs.
On the Codespaces page of your repository settings, click the ellipsis to the right of the prebuild configuration you want to delete.
In the dropdown menu, click Delete.
Click OK to confirm the deletion.
It may be useful to manually trigger a workflow run for a prebuild configuration. Generally this is only necessary if you are debugging a problem with the workflow for a prebuild configuration.
On the Codespaces page of your repository settings, click the ellipsis to the right of the prebuild configuration whose workflow you want to trigger.
In the dropdown menu, click Manually trigger.
By default, the GitHub Actions workflow for a prebuild configuration can only access its own repository contents. Your project may use additional resources to build the development environment, such as files in other repositories, packages, GHCR images, and APIs. To allow your prebuild setup to access these resources, you will need to create a new personal account and then use this account to create a personal access token (PAT) with the appropriate scopes.
Create a new personal account on GitHub.
Warning: Although you can generate the PAT using your existing personal account, we strongly recommend creating a new account with access only to the target repositories required for your scenario. This is because the access token's
repositorypermission grants access to all of the repositories that the account has access to. For more information, see "Signing up for a new GitHub account" and "Security hardening for GitHub Actions."
Give the new account read access to the required repositories. 詳細は、「Organization のリポジトリへの個人のアクセスを管理する」を参照してください。
While signed into the new account, create a PAT with the
reposcope. Optionally, if the prebuild will need to download packages from the GitHub コンテナレジストリ, also select the
If the prebuild will use a package from the GitHub コンテナレジストリ, you will need to either grant the new account access to the package or configure the package to inherit the access permissions of the repository you are prebuilding. 詳しい情報については「パッケージのアクセス制御と可視性」を参照してください。
Copy the token string. You will assign this to a Codespaces repository secret.
Sign back into the account that has admin access to the repository.
In the repository for which you want to create Codespaces prebuilds, create a new Codespaces repository secret called
CODESPACES_PREBUILD_TOKEN, giving it the value of the token you created and copied. For more information, see "Managing encrypted secrets for your repository and organization for Codespaces."
The PAT will be used for all subsequent prebuild templates created for your repository. Unlike other Codespaces repository secrets, the
CODESPACES_PREBUILD_TOKEN secret is only used for prebuilding and will not be available to use in codespaces created from your repository.