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GitHub Authentication Provider

The Backstage core-plugin-api package comes with a GitHub authentication provider that can authenticate users using GitHub or GitHub Enterprise OAuth.

Create an OAuth App on GitHub​

To add GitHub authentication, you must create either a GitHub App, or an OAuth App from the GitHub developer settings. The Homepage URL should point to Backstage's frontend, while the Authorization callback URL will point to the auth backend.

Note that if you're using a GitHub App, the allowed scopes are configured as part of that app. This means you need to verify what scopes the plugins you use require, so be sure to check the plugin READMEs for that information.

Settings for local development:

  • Application name: Backstage (or your custom app name)
  • Homepage URL: http://localhost:3000
  • Authorization callback URL: http://localhost:7007/api/auth/github/handler/frame

Difference between GitHub Apps and GitHub OAuth Apps​

GitHub Apps handle OAuth scope at the app installation level, meaning that the scope parameter for the call to getAccessToken in the frontend has no effect. When calling getAccessToken in open source plugins, one should still include the appropriate scope, but also document in the plugin README what scopes are required for GitHub Apps.

Configuration​

The provider configuration can then be added to your app-config.yaml under the root auth configuration:

auth:
  environment: development
  providers:
    github:
      development:
        clientId: ${AUTH_GITHUB_CLIENT_ID}
        clientSecret: ${AUTH_GITHUB_CLIENT_SECRET}
        ## uncomment if using GitHub Enterprise
        # enterpriseInstanceUrl: ${AUTH_GITHUB_ENTERPRISE_INSTANCE_URL}
        signIn:
          resolvers:
            # See https://backstage.io/docs/auth/github/provider#resolvers for more resolvers
            - resolver: usernameMatchingUserEntityName

The GitHub provider is a structure with these configuration keys:

  • clientId: The client ID that you generated on GitHub, e.g. b59241722e3c3b4816e2
  • clientSecret: The client secret tied to the generated client ID.
  • enterpriseInstanceUrl (optional): The base URL for a GitHub Enterprise instance, e.g. https://ghe.<company>.com. Only needed for GitHub Enterprise.
  • callbackUrl (optional): The callback URL that GitHub will use when initiating an OAuth flow, e.g. https://your-intermediate-service.com/handler. Only needed if Backstage is not the immediate receiver (e.g. one OAuth app for many backstage instances).
  • signIn: The configuration for the sign-in process, including the resolvers that should be used to match the user from the auth provider with the user entity in the Backstage catalog (typically a single resolver is sufficient).

Resolvers​

This provider includes several resolvers out of the box that you can use:

  • emailMatchingUserEntityProfileEmail: Matches the email address from the auth provider with the User entity that has a matching spec.profile.email. If no match is found it will throw a NotFoundError.
  • emailLocalPartMatchingUserEntityName: Matches the local part of the email address from the auth provider with the User entity that has a matching name. If no match is found it will throw a NotFoundError.
  • usernameMatchingUserEntityName: Matches the username from the auth provider with the User entity that has a matching name. If no match is found it will throw a NotFoundError.
Note

The resolvers will be tried in order, but will only be skipped if they throw a NotFoundError.

If these resolvers do not fit your needs you can build a custom resolver, this is covered in the Building Custom Resolvers section of the Sign-in Identities and Resolvers documentation.

Backend Installation​

To add the provider to the backend we will first need to install the package by running this command:

from your Backstage root directory
yarn --cwd packages/backend add @backstage/plugin-auth-backend-module-github-provider

Then we will need to add this line:

in packages/backend/src/index.ts
backend.add(import('@backstage/plugin-auth-backend'));
backend.add(import('@backstage/plugin-auth-backend-module-github-provider'));

Adding the provider to the Backstage frontend​

To add the provider to the frontend, add the githubAuthApi reference and SignInPage component as shown in Adding the provider to the sign-in page.