GraphGate is a high-performance Apollo Federation compatible implementation written in Rust. It enables you to build a distributed GraphQL architecture by composing multiple services into a unified schema.
- High Performance: Built in Rust for optimal memory usage and execution speed
- Federation Compatibility: Compatible with Apollo Federation specifications
- Directive-Based Schema Composition: Uses GraphQL directives to compose schemas from multiple services
- Optimized Query Planning: Creates efficient query execution plans to minimize service calls
- Modular Architecture: Component-based design for easy maintenance and extensibility
GraphGate implements a range of Apollo Federation directives through a modular Directive Registry Pattern:
- @key: Marks a type as an entity and defines the fields that uniquely identify it across services
- @requires: Specifies fields from another service that must be fetched before resolving a field
- @provides: Indicates that a field can fetch specific subfields of an entity from another service
- @tag: Adds metadata to fields or types to enable runtime behavior modifications
- @external: Marks a field as defined in another service
- @shareable: Marks a type as shareable across subgraphs
- @link: Links definitions from an external specification to the schema
- @inaccessible: Marks fields or types that should not be accessible to clients
GraphGate is organized into several crates:
- schema: Handles schema composition and validation of federated services
- planner: Creates efficient query execution plans using directive information
- handler: Manages request handling and communication with services
- validation: Performs schema validation against Federation specifications
The planner uses a modular Directive Registry Pattern where each directive handler implements the DirectiveHandlerTrait interface. This makes the codebase more maintainable and allows for easier addition of new directive handlers.
docker run -p 4000:4000 graphgate/graphgateCheck the examples directory for sample services showing how to use GraphGate with various directive combinations:
- accounts.rs: User authentication and account management service with entity resolution
- products.rs: Product catalog service demonstrating entity relationships
- reviews.rs: Product review service showcasing more complex entity relations and directive usage
- Federation v2 Features: Some advanced Federation v2 features are still in development
- Subscription Support: Limited support for GraphQL subscriptions across federated services
- Custom Scalars: Limited support for custom scalar types across services
- Error Handling: Error propagation from subgraphs could be improved
- Advanced Query Optimization: Some complex query patterns could benefit from further optimization
Contributions are welcome! GraphGate is actively being improved, and we appreciate help with:
- Implementing additional directive handlers
- Improving performance optimizations
- Enhancing error handling and reporting
- Expanding test coverage
- Improving documentation
This project is licensed under the MIT/Apache-2.0 License - see the LICENSE file for details.