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Federation Supergraph

GraphQL Mesh v0 documentation (superseded by v1): Federation Supergraph

You can use GraphQL Mesh as a [Federation](https://the-guild.dev/graphql/hive/federation] supergraph in multiple ways. You can either provide each source, and let Mesh build your supergraph, or you can provide prebuilt Supergraph SDL.

Consuming prebuilt Supergraph SDL

If you use Apollo Rover CLI or GraphQL Hive to compose your subgraphs, you can easily consume the prebuilt supergraph SDL by using Supergraph handler;

npm i @graphql-mesh/supergraph
sources:
  - name: Supergraph
    handler:
      supergraph:
        source: http://some-source.com/supergraph.graphql # it can be a path from the file system `./supergraph.graphql`
        schemaHeaders:
          myTokenHeader: MY_TOKEN_VALUE

Configuring subgraphs within the supergraph

You can also configure subgraphs within the supergraph by providing the subgraph name in order to change the endpoint and headers for each subgraph.

sources:
  - name: Supergraph
    handler:
      supergraph:
        source: http://some-source.com/supergraph.graphql
        subgraphs:
          - name: accounts
            endpoint: http://localhost:9871/graphql
            operationHeaders: # You can use context variables here
              Authorization: "Bearer {context.headers['x-accounts-token']}"
          - name: reviews
            endpoint: '{env.REVIEWS_ENDPOINT:https://default-reviews.com/graphql}'
            operationHeaders:
              Authorization: "Bearer {context.headers['x-reviews-token']}"

Config API Reference

  • source (type: String, required) - A file path to your Supergraph Schema If you provide a path to a code file(js or ts), other options will be ignored and the schema exported from the file will be used directly.
  • schemaHeaders (type: Any)
  • operationHeaders (type: Any)
  • batch (type: Boolean)
  • subgraphs (type: Array of Object, required):
    • name (type: String, required) - The name of the subgraph you want to configure
    • endpoint (type: String) - A url or file path to your remote GraphQL endpoint. If you provide a path to a code file(js or ts), other options will be ignored and the schema exported from the file will be used directly.
    • operationHeaders (type: JSON) - JSON object representing the Headers to add to the runtime of the API calls only for operation during runtime
    • useGETForQueries (type: Boolean) - Use HTTP GET for Query operations
    • method (type: String (GET | POST)) - HTTP method used for GraphQL operations
    • credentials (type: String (omit | include)) - Request Credentials if your environment supports it. See more

@default “same-origin”

  • webSocketImpl (type: String) - Path to a custom W3 Compatible WebSocket Implementation
  • source (type: String) - Path to the introspection You can separately give schema introspection or SDL
  • subscriptionsProtocol (type: String (SSE | WS | LEGACY_WS)) - SSE - Server Sent Events WS - New graphql-ws LEGACY_WS - Legacy subscriptions-transport-ws
  • subscriptionsEndpoint (type: String) - URL to your endpoint serving all subscription queries for this source
  • retry (type: Int) - Retry attempts if fails
  • timeout (type: Int) - Timeout in milliseconds
  • connectionParams (type: JSON) - JSON object representing the connectionParams from a WebSocket connection to add to the runtime of the API calls only for operation during runtime. More information about the WebSocket connectionParams:

Using Mesh to build the supergraph

You can provide the existing subgraphs within GraphQL Mesh, or you can use Federation Subgraph to create subgraphs from regular sources.

sources:
  - name: accounts
    handler:
      graphql:
        endpoint: http://localhost:9871/graphql
    transforms:
      - federation:
          types:
            - name: User
              config:
                key:
                  - fields: id
                resolveReference:
                  queryFieldName: user
                  args:
                    id: '{root.id}'
  - name: reviews
    handler:
      graphql:
        endpoint: http://localhost:9872/graphql
  - name: products
    handler:
      graphql:
        endpoint: http://localhost:9873/graphql
  - name: inventory
    handler:
      graphql:
        endpoint: http://localhost:9874/graphql

You can check our working example on the repo.