Federation Subgraph Transform

This transform allows to create subgraphs from your regular sources which don't have any federation annotations. This transform uses graphql-transform-federation package.

npm i @graphql-mesh/transform-federation

How to use?

Add the following configuration to your Mesh config file:

transforms:
  - federation:
      types:
        # Ensure the root queries of this schema show up the combined schema
        - name: Query
          config:
            extends: true
        - name: Product
          config:
            # extend Product {
            extend: true
            # Product @key(fields: "id") {
            key:
              fields:
                - id
            fields:
              # id: Int! @external
              - name: id
                config:
                  external: true
            resolveReference:
              queryFieldName: user

Add Reference Resolver as a Code File

To add more complex business logic, you can point to a code file that exports a resolver function.

resolveReference: ./userResolveReference.ts

// So we can point to an existing query field to resolve that entity
export default function (root, context, info) {
  return context.accounts.Query.user({ root, args: { id: root.id }, context, info })
}

• types (type: Array of Object, required):
  • name (type: String, required)
  • config (type: Object):
    • key (type: Array of Object):
      • fields (type: String)
    • shareable (type: Boolean)
    • extends (type: Boolean)
    • fields (type: Array of Object, required):
      • name (type: String, required)
      • config (type: Object, required):
        • external (type: Boolean)
        • provides (type: Object):
          • fields (type: String)
        • requires (type: Object):
          • fields (type: String)
        • tag (type: Object):
          • name (type: String)
        • inaccessible (type: Boolean)
        • override (type: Object):
          • from (type: String)
    • resolveReference - One of:
      • String
      • object:
        • queryFieldName (type: String, required) - Name of root field name that resolves the reference
        • args (type: JSON) - You need configure the arguments for that field;

args:
  someArg: "{root.someKeyValue}"

• version (type: String) - Version of the federation spec Default: v2.0