View Source Google Tutorial

This is a quick tutorial on how to configure Google authentication.

First you'll need a registered application in Google Cloud, in order to get your OAuth 2.0 Client credentials.

1. On the Cloud's console Quick access section select APIs & Services, then Credentials
2. Click on + CREATE CREDENTIALS and from the dropdown select OAuth client ID
3. From the google developers console, we will need: client_id & client_secret

Next we configure our resource to use google credentials:

defmodule MyApp.Accounts.User do
  use Ash.Resource,
    extensions: [AshAuthentication],
    domain: MyApp.Accounts

  attributes do
    ...
  end

  authentication do
    strategies do
      oauth2 :google do
        client_id MyApp.Secrets
        redirect_uri MyApp.Secrets
        client_secret MyApp.Secrets end
        base_url MyApp.Secrets
      end
    end
  end
end

Please check the guide on how to properly configure your Secrets Then we need to define an action that will handle the oauth2 flow, for the google case it is :register_with_google it will handle both cases for our resource, user registration & login.

defmodule MyApp.Accounts.User do
  use Ash.Resource,
    extensions: [AshAuthentication],
    domain: MyApp.Accounts

  # ...
  actions do
    create :register_with_google do
      argument :user_info, :map, allow_nil?: false
      argument :oauth_tokens, :map, allow_nil?: false
      upsert? true
      upsert_identity :email

      change AshAuthentication.GenerateTokenChange

      # Required if you have the `identity_resource` configuration enabled.
      change AshAuthentication.Strategy.OAuth2.IdentityChange

      change fn changeset, _ ->
        user_info = Ash.Changeset.get_argument(changeset, :user_info)

        Ash.Changeset.change_attributes(changeset, Map.take(user_info, ["email"]))
      end
    end
  end

  # ...

end