Java Spring Federated GraphQL Subgraph

This is an example application template that can be used to create Federated GraphQL subgraph using Spring GraphQL. You can use this template from Rover with rover template use --template subgraph-java-spring-graphql.

This example application implements following GraphQL schema:

directive @contact(
    "Contact title of the subgraph owner"
    name: String!
    "URL where the subgraph's owner can be reached"
    url: String
    "Other relevant notes can be included here; supports markdown links"
    description: String
) on SCHEMA

schema
@contact(
    name: "FooBar Server Team"
    url: "https://myteam.slack.com/archives/teams-chat-room-url"
    description: "send urgent issues to [#oncall](https://yourteam.slack.com/archives/oncall)."
)
@link(
    url: "https://specs.apollo.dev/federation/v2.0",
    import: ["@key"]
) {
    query: Query
}

type Query {
    foo(id: ID!): Foo
}
type Foo @key(fields: "id") {
    id: ID!
    name: String
}

Build

This project uses Maven and requires Java 17+ runtime. In order to build the project locally (which will also execute all the tests), simply run the clean install goals.

./mvnw clean install

NOTE: in order to ensure you use the right version of Maven we highly recommend to use the provided wrapper script

Code Quality

Build is configured with JaCoCo plugin that measures the code coverage. It is configured to run as part of the build lifecycle and will generate its report under target/site.

Example integration test is provided. It starts up the SpringBoot server and executes example queries against it. Run verify goal to execute tests and calculate the coverage.

./mvnw clean verify

Continuous Integration

This project comes with some example build actions that will trigger on PR requests and commits to the main branch.

Run

To start the GraphQL server:

• Run Application.java directly from your IDE
• Alternatively you can also run the Spring Boot plugin directly from the command line

./mvnw spring-boot:run

Once the app has started you can explore the example schema by opening the GraphQL Playground endpoint at http://localhost:8080/playground and begin developing your supergraph with rover dev --url http://localhost:8080/graphql --name my-sugraph.

Apollo Studio Integration

1. Set these secrets in GitHub Actions:
   1. APOLLO_KEY: An Apollo Studio API key for the supergraph to enable schema checks and publishing of the subgraph.
   2. APOLLO_GRAPH_REF: The name of the supergraph in Apollo Studio.
   3. PRODUCTION_URL: The URL of the deployed subgraph that the supergraph gateway will route to.
2. Set SUBGRAPH_NAME in .github/workflows/checks.yaml and .github/workflows/deploy.yaml
3. Remove the if: false lines from .github/workflows/checks.yaml and .github/workflows/deploy.yaml to enable schema checks and publishing.
4. Write your custom deploy logic in .github/workflows/deploy.yaml.
5. Send the Router-Authorization header from your Cloud router and set the ROUTER_SECRET environment variable wherever you deploy this to.

Additional Resources

• Spring GraphQL documentation
• Spring Boot documentation
• Maven documentation