Federation 2 representation query

[sijonelis]

Hi all, I am trying to set up a federation 2 graph with entity representations in different subgraphs (as described in apollo spec)

I have set the entities up in two java services and managed to get the correct query plan:

QueryPlan {
  Sequence {
    Fetch(service: "General Ledger") {
      {
        journal(journalId: 30) {
          id
          name
          companyId
          company {
            __typename
            id
          }
        }
      }
    },
    Flatten(path: "journal.company") {
      Fetch(service: "MasterData") {
        {
          ... on Company {
            __typename
            id
          }
        } =>
        {
          ... on Company {
            name
          }
        }
      },
    },
  },
}

Then i tried to define the representation query as such, but it was not hit:

  @DgsEntityFetcher(name = "Company")
  public CompletableFuture<CompanyResource> company(DgsDataFetchingEnvironment dfe, Map<String, Object> values) {
    DataLoader<Long, CompanyResource> dataLoader = dfe.getDataLoader(CompanyDataLoader.class);
    return dataLoader.load((Long)values.get("id"));
  }

Difference between this and v1 federation is that in V1 the @DgsEntityFetcher would live in a different service than the Company entity, but in federation V2, @DgsEntityFetchershould live in the same service as the entity@DgsComponentforCompany`.

EDIT
Solved my problem, which was mostly due to an incorrect interpretation of federation 2 and how it merges into the DGS. I think it would be nice to have an example for it in the docs, which currently only have federation 1 example.
Would the community be interested in such a pr?