How should one loadTypeDefs for federated schemata?

[jacob-carpenter]

Hey 👋 we're still in the process of upgrading all of our graph ql dependencies to the latest library versions. As such, we're having to update how we were building out our schemata from the importSchema paradigm to the buildSubgraphSchema paradigm but we were having some issues with missing federated types, or missing extended types that used to be resolve appropriately.

Before:

const typeDefs = gql`
  ${importSchema(path.join(__dirname, './schema.graphql'))}
`
export default buildFederatedSchema({
  resolvers,
  typeDefs,
})

After:

const typeDefs = gql`
  ${loadSchemaSync(['./node_modules/@casecommons/**/*.graphql', path.join(__dirname, 'schema.graphql')], {
    loaders: [new GraphQLFileLoader()]
  })}
`

export default buildSubgraphSchema([
  {
    typeDefs,
    resolvers: resolvers as any,
    // resolvers,
  },
])

I can try to bypass the issue with using the assumeValidSDL: true flag on the loadSchemaSync call, but i was curious if there is a better way to build out the fully resolved schemata with the federation resolution (is there a typedef loader that will resolve federation)? Or is there a better strategy to build the schema that we are missing?

[ardatan]

You can load files using loadFiles(doesn't support #import);
https://www.graphql-tools.com/docs/schema-merging#file-loading
Or you can add Federation SDL for missing definitions;
https://www.apollographql.com/docs/federation/federation-spec/#federation-schema-specification