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Datasources
GraphQL Federation

GraphQL Federation DataSource

Federation helps companies implement GraphQL at scale and allows you to combine multiple GraphQL APIs (subgraphs) into a single Supergraph. WunderGraph has native support for Apollo federation, it supports Queries, Mutations as well as Subscriptions.

It brings a lot of useful features to implement Graphs across multiple teams in a "federated" way, hence the name. It was invented and specified by Apollo (opens in a new tab).

WunderGraph is extremely fast executing GraphQL Operations and is therefor a great fit for a Federation Gateway.

Add a Apollo Federation DataSource

To add a Apollo Federation data source, edit wundergraph/wundergraph.config.ts and introspect the SubGraphs like the config below.

import type { WunderGraphConfig } from '@wundergraph/sdk';
import { federation } from '@wundergraph/sdk/datasources';
 
const federatedApi = federation({
  namespace: 'federated',
  upstreams: [
    {
      url: 'http://localhost:4001/graphql',
    },
    {
      url: 'http://localhost:4002/graphql',
    },
    {
      url: 'http://localhost:4003/graphql',
    },
    {
      url: 'http://localhost:4004/graphql',
    },
  ],
});
 
export default {
  datasources: [federatedApi],
} satisfies WunderGraphConfig;

Simply add all the URLs of your SubGraphs to the upstreams array.

Authenticated GraphQL APIs

If you need to authenticate against your federated GraphQL API, you can use the introspection option to add custom headers to your requests.

const federatedApi = federation({
  namespace: 'github',
  upstreams: [
    {
      url: 'http://localhost:4001/graphql',
      introspection: {
        headers(builder) {
          return builder.addStaticHeader('Authorization', `Bearer ${process.env.SECRET}`);
        },
      },
    },
  ],
});

To forward the Authorization header from the client to the upstream or set static headers, you can use the headers option.

const github = graphql({
  namespace: 'github',
  upstreams: [
    {
      url: 'http://localhost:4001/graphql',
      headers(builder) {
        return (
          builder
            // We forward `X-Secret` to the `Authorization` header.
            .addClientRequestHeader('Authorization', 'X-Secret')
        );
      },
    },
  ],
});

The X-Github-Token header will be forwarded from the client to the upstream, while the X-Github-Next-Global-ID header will be added to every request.

Learn more

GraphQLREST / OpenAPI