Federated schema with local subgraph files

Hello –

We are working on a green-field project and we would like to start out by building a monolithic with schema federation. By that I mean, we would have a single code-base with multiple subgraphs that form a supergraph. However, each subgraph won’t be a service on its own yet. They will just be files on a single code-base.

Can we use the Rover CLI compose command to form a supergraph from local files representing subgraphs? Seems like every example I see at Working with supergraphs - Rover CLI - Apollo GraphQL Docs has a route_url field on the .yml file that describes the subgraphs to be composed. Could we leave route_url out and just have schema.file?

Thanks.