Unable to use several dgraph instances together with GraphQL federation

[1Maxnet1]

As already discussed here: https://discuss.dgraph.io/t/cannot-use-apollo-federation-with-multiple-dgraph-instances/15562 dgraph automatically generates helper types when loading a GraphQL schema. When I now want to compose a supergraph for two dgraph instances, I am unable to composite schema (e.g. with apollo-rover or hive cli) to load into my gateway. Is there any possibility to deactivate the generation of helper types to allow to federate multiple graph databases?

[matthewmcneely]

@1Maxnet1 This is a known limitation of Dgraph's GraphQL federation support, the type generation isn't fully federation-aware for extended types. I don't think this will be a priority in the near term. You may be able to work around it by (taking the example in the forum):

1. In the primary "User" subgraph, define the type normally.
2. In the "Review" subgraph, use Dgraph's @generate directives to disable auto-generation
3. Configure Rover to use the _service endpoint for schema introspection

query { _service { sdl } } 

[1Maxnet1]

Thanks a lot. I was able to resolve the problems arising due to mutations and queries. However the generated Types ( mentioned also here https://docs.dgraph.io/graphql/schema/reserved/) still conflict. Is i possible to disable the auto-generation here too?

[matthewmcneely]

What types are still conflicting (using the _service schema hook)? Can you send the error from Rover?

[1Maxnet1]

What types are still conflicting (using the _service schema hook)?

xxPatch, xxOrderable and xxHasFilter for all the Types that are owned by one schema and extended in another schema.

Can you send the error from Rover?

error[E029]: Encountered 9 build errors while trying to build a supergraph. Caused by: EMPTY_MERGED_INPUT_TYPE: None of the fields of input object type "DatasetPatch" are consistently defined in all the subgraphs defining that type. As only fields common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_INPUT_TYPE: None of the fields of input object type "DivisionPatch" are consistently defined in all the subgraphs defining that type. As only fields common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_INPUT_TYPE: None of the fields of input object type "PredictiveModelPatch" are consistently defined in all the subgraphs defining that type. As only fields common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_ENUM_TYPE: None of the values of enum type "DatasetHasFilter" are defined consistently in all the subgraphs defining that type. As only values common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_ENUM_TYPE: None of the values of enum type "DatasetOrderable" are defined consistently in all the subgraphs defining that type. As only values common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_ENUM_TYPE: None of the values of enum type "DivisionHasFilter" are defined consistently in all the subgraphs defining that type. As only values common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_ENUM_TYPE: None of the values of enum type "DivisionOrderable" are defined consistently in all the subgraphs defining that type. As only values common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_ENUM_TYPE: None of the values of enum type "PredictiveModelHasFilter" are defined consistently in all the subgraphs defining that type. As only values common to all subgraphs are merged, this would result in an empty type. EMPTY_MERGED_ENUM_TYPE: None of the values of enum type "PredictiveModelOrderable" are defined consistently in all the subgraphs defining that type. As only values common to all subgraphs are merged, this would result in an empty type. The subgraph schemas you provided are incompatible with each other. See https://www.apollographql.com/docs/federation/errors/ for more information on resolving build errors. 

Note that this is not the schema files from the example, but my own types. However, the issue is still the same, as I did not define any of these Types but they are generated by dgraph according to the docs here: https://docs.dgraph.io/graphql/schema/reserved/