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Google Authentication Provider

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

Create OAuth Credentials​

To support Google authentication, you must create OAuth credentials:

  1. Log in to the Google Console
  2. Select or create a new project from the dropdown menu on the top bar
  3. Navigate to APIs & Services > Credentials
  4. Click Create Credentials and choose OAuth client ID
  5. Configure an OAuth consent screen, if required
    • For local development, you do not need to enter any Authorized domain
    • For scopes, select openid, auth/userinfo.email and auth/userinfo.profile
    • Add yourself as a test user, if using External user type
  6. Set Application Type to Web Application with these settings:
  7. Click Create

Configuration​

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

auth:
  environment: development
  providers:
    google:
      development:
        clientId: ${AUTH_GOOGLE_CLIENT_ID}
        clientSecret: ${AUTH_GOOGLE_CLIENT_SECRET}
        signIn:
          resolvers:
            # See https://backstage.io/docs/auth/google/provider#resolvers for more resolvers
            - resolver: emailMatchingUserEntityAnnotation

The Google provider is a structure with two configuration keys:

  • clientId: The client ID that you generated, e.g. 10023341500512-beui241gjwwkrdkr2eh7dprewj2pp1q.apps.googleusercontent.com
  • clientSecret: The client secret tied to the generated client ID.

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.
  • emailMatchingUserEntityAnnotation: Matches the email address from the auth provider with the User entity where the value of the google.com/email annotation matches. 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-google-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-google-provider'));

Adding the provider to the Backstage frontend​

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