Lighthouse

# Federation: Getting Started

Experimental: not enabled by default, not guaranteed to be stable.

Federation enables you to combine GraphQL services into a single unified data graph. Read more about the core concepts and motivation in the Apollo Federation docs (opens new window).

Lighthouse can act as a federation capable service as described in the Apollo Federation specification (opens new window) v2. It can not serve as a federation gateway (opens new window).

# Setup

Add the service provider to your config/app.php:

'providers' => [
    \Nuwave\Lighthouse\Federation\FederationServiceProvider::class,
],

# Publishing Your Schema

In order to generate a .graphql schema file suitable for publishing, use the --federation option of print-schema.

php artisan lighthouse:print-schema --federation

# Apollo Federation v2

Support for Apollo Federation v2 is opt-in and can be enabled by adding the following to your schema. See the Apollo documentation on federated directives (opens new window) for the latest spec.

extend schema
  @link(
    url: "https://specs.apollo.dev/federation/v2.3"
    import: [
      "@composeDirective"
      "@extends"
      "@external"
      "@inaccessible"
      "@interfaceObject"
      "@key"
      "@override"
      "@provides"
      "@requires"
      "@shareable"
      "@tag"
    ]
  )

# Federated tracing

In order to use federated tracing, you need to enabled tracing and set the driver to Nuwave\Lighthouse\Tracing\FederatedTracing\FederatedTracing::class in your config/lighthouse.php:

'tracing' => [
    'driver' => Nuwave\Lighthouse\Tracing\FederatedTracing\FederatedTracing::class,
],

Note that federated tracing requires google/protobuf to be installed (for better performance you can also install the protobuf php extension).

# Unsupported features

Some features of the Apollo Federation specification are not supported by Lighthouse:

# Renaming directives

Renaming imported directives is not supported. You can only use the default names.

extend schema
  @link(
    url: "https://specs.apollo.dev/federation/v2.3"
    import: [{ name: "@key", as: "@uniqueKey" }, "@shareable"]
  )

# Namespaced directives

Using directives from a namespace without an import is not supported. You should import the directive and use the default name.

extend schema
  @link(url: "https://specs.apollo.dev/federation/v2.3", import: ["@key"])

type Book @federation__shareable {
  title: String!
}

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