Apollo Federation on the JVM

Apollo Federation is a powerful, open architecture that helps you create a unified supergraph that combines multiple GraphQL APIs. federation-graphql-java-support provides Apollo Federation support for building subgraphs in the graphql-java ecosystem. Individual subgraphs can be run independently of each other but can also specify relationships to the other subgraphs by using Federated directives. See Apollo Federation documentation for details.

graph BT;
  gateway([Supergraph<br/>gateway]);
  serviceA[Users<br/>subgraph];
  serviceB[Products<br/>subgraph];
  serviceC[Reviews<br/>subgraph];
  gateway --- serviceA & serviceB & serviceC;

Modules

Federation JVM Support

federation-graphql-java-support is built on top of graphql-java and provides transformation logic to make your GraphQL schemas Federation compatible. SchemaTransformer adds common Federation type definitions (e.g. _Any scalar, _Entity union, Federation directives, etc) and allows you to easily specify your Federated entity resolvers.

This project also provides a set of Federation aware instrumentations:

• CacheControlInstrumentation - instrumentation that computes a max age for an operation based on @cacheControl directives
• FederatedTracingInstrumentation - instrumentation that generates trace information for federated operations

See module README for details.

Subscription HTTP Callback Support for Spring GraphQL

GraphQL subscriptions enable clients to receive continual, real-time updates whenever new data becomes available. Unlike queries and mutations, subscriptions are long-lasting. This means a client can receive multiple updates from a single subscription.

Spring GraphQL provides out of box support for GraphQL subscriptions over WebSockets using graphql-transport-ws protocol. This library adds support for subscriptions using Apollo HTTP callback protocol.

See Apollo Router for additional details about Federation and Subscription support. See module README for library details.

Contact

If you have a specific question about the library or code, please start a discussion in the Apollo community forums.

Contributing

To get started, please fork the repo and checkout a new branch. You can then build the library locally with Gradle

./gradlew clean build

See more info in CONTRIBUTING.md.

After you have your local branch set up, take a look at our open issues to see where you can contribute.

Security

For more info on how to contact the team for security issues, see our Security Policy.

License

This library is licensed under The MIT License (MIT).