apollo-kotlin-ffs is an Apollo compiler plugin that adds Federation Foreign Schemas (FFS) to the Apollo Compiler.

This is useful if you want to use Apollo Kotlin codegen with a schema that contains federation subgraph directives.

Those schemas are typically meant to be consumed by a server framework and not by a client. Clients should use introspection results or the full schema after it has been processed by the server framework.

Sometimes getting such a client schema is cumbersome. In those cases, apollo-kotlin-ffs adds the federation directives to the Apollo Kotlin compiler so that it can process the backend SDL.

[!NOTE] apollo-kotlin-ffs does not do any composition or any query planning. It is merely a tool to help clients validate schemas that are otherwise meant for server consumption.

To use apollo-kotlin-ffs in your project, add it as a plugin to your Apollo Kotlin service:

apollo {
  service("service") {
    packageName.set("com.example")

    plugin("com.apollographql.ffs:apollo-kotlin-ffs:0.0.0")
  }
}

See https://github.com/apollographql/apollo-kotlin/issues/6221 for more context.

📚 Documentation

The Kdoc API reference can be found at:
https://apollographql.github.io/apollo-kotlin-ffs/kdoc