Federating Absinthe Elixir w/ GraphQL Mesh

Federating the Absinthe GraphQL elixir library with GraphQL Mesh.

Setup

Mac OS Setup

brew install gpg asdf
asdf plugin add nodejs https://github.com/asdf-vm/asdf-nodejs.git
asdf plugin-add elixir https://github.com/asdf-vm/asdf-elixir.git
asdf install

Run GraphQL Mesh Example App

GraphQL Mesh includes a federation example federating 4 nodejs graphs. This example replaces the accounts nodejs app with Absinthe.

yarn install
yarn start

The example query should run successfully.

How it works

The GraphQL Mesh config file .meshrc.yml contains a list of APIs that can be included in the mesh. GraphQL Mesh supports 12 API sources including GraphQL (with or without federation support), gRPC, OpenAPI, and others.

When adding a graphql source that does not support federation, a transform can be used.

Here is an example of extending the root query and allowing other fields to access the accounts' user fields.

  - name: accounts
    handler:
      graphql:
        endpoint: http://localhost:9871/graphql
    transforms:
      - federation:
          types:
            - name: Query # Note: Absinthe defaults the root query type name to "RootQueryType"
              config:
                extend: true
            - name: User
              config:
                keyFields:
                  - id
                resolveReference:
                  queryFieldName: user

The query name on line 8 of the YAML above needs to match the name of the root query in Absinthe.

query name: "Query" do
  # ...
end