backstage/docs/plugins/github-apps.md

Using GithubApps for backend authentication

Backstage can be configured to use GitHub Apps for backend authentication. This come with advantages such as higher rate limits and that Backstage can act as an application instead of a user or bot account.

It also provides a much clearer and better authorization model as a opposed to the OAuth apps and their respective scopes.

Caveats

• It's not possible to have multiple backstage GitHub Apps installed in the same GitHub organization be managed by Backstage. We currently don't check through all the registered GitHub Apps to see which ones are installed for a particular repository. We just respect global Organization installs right now.
• App permissions is not managed by Backstage. They're created with some simple default permissions which you are free to change as you need, but you will need to update them in the GitHub web console, not in Backstage right now. The permissions that are defaulted are `metadata
• The created GitHub App is private by default, this is most likely what you want for github.com but it's recommended to make your application public for GitHub Enterprise in order to share application across your GHE organizations.

A GitHub app created with backstage-cli create-github-app will have read access by default. You have to manually update the GitHub App settings in GitHub to grant the app more permissions if needed.

Using the CLI (public GitHub only)

You can use the backstage-cli to create GitHub App' using a manifest file that we provide. This gives us a way to automate some of the work required to create a GitHub app.

You can read more about the backstage-cli create-github-app method here

Once you've gone through the CLI command, it should produce a yaml file in the root of the project which you can then use as an include in your app-config.yaml. You can go ahead and skip to here if you've got to this part.

GitHub Enterprise

You have to create the GitHub Application manually using these instructions as GitHub Enterprise does not support creation of apps from manifests.

Once the application is created you have to generate a private key for the application it in a yaml file.

The yaml file must include the following information. Please note that the indentation for the privateKey is required.

appId: 1
clientId: client id
clientSecret: client secret
webhookSecret: webhook secret
privateKey: |
  -----BEGIN RSA PRIVATE KEY-----
  ...Key content...
  -----END RSA PRIVATE KEY-----

Including in Integrations Config

Once the credentials are stored in a yaml file generated by create-github-app or manually by following the GitHub Enterprise instructions they can be included in the app-config.yaml under the integrations section.

integrations:
  github:
    - host: github.com
    apps:
        - $include: example-backstage-app-credentials.yaml