How should I configure the ObjectMapper so that it can deserialize

Entity

in

SearchQueryResponse

of a GraphQL search request? I got the following exception when trying to turn the code below it. I used the auto generated graphql client code and I confirmed that the raw response string the client received is correct.

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of com.linkedin.datahub.graphql.generated.Entity (no Creators, like default constructor, exist): abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information

final SearchInput searchInput =
        SearchInput.builder()
            .setType(EntityType.DATASET)
            .setQuery("")
            .setStart(0)
            .setCount(10)
            .build();
    final SearchQueryRequest searchQueryRequest =
        SearchQueryRequest.builder().setInput(searchInput).build();

    GraphQLResponseProjection graphQLResponseProjection =
        new SearchResultsResponseProjection()
            .start()
            .count()
            .total()
            .searchResults(
                new SearchResultResponseProjection()
                    .entity(new EntityResponseProjection().urn().type()));

    GraphQLRequest graphQLRequest =
        new GraphQLRequest(searchQueryRequest, graphQLResponseProjection);
    final SearchQueryResponse searchQueryResponse =
        getRestTemplate()
            .exchange(
                URI.create(GRAPHQL_ENDPOINT),
                <http://HttpMethod.POST|HttpMethod.POST>,
                createHttpEntity(graphQLRequest),
                SearchQueryResponse.class)
            .getBody();

    System.out.println(searchQueryResponse.search());

@green-football-43791 @bulky-soccer-26729

Hey Jinlin,

Entity

is a GraphQL auto-generated interface. You would need to create a custom deserialiser that routes to the appropriate class based on the

EntityType

property of the object. This is not something we have in DataHub as of right now.

Basically this happens because there isn't a well defined way for the ObjectMapper to route to the subtype. The way to work around this from the model side is to provide a defining attribute that determines what subtype it should be deserialized to. If you take a look at the OpenAPI models we do this with a discriminator property, but the GraphQL models don't have the equivalent so a custom deserializer that specifies what concrete type to route to is necessary.

Thank you @orange-night-91387 @incalculable-ocean-74010!

schemaMetadata is a query and not a field so it doesn't get set as a property in the generated type

In addition to the

schemaMetadata

in this thread, we have also found the

IngestionSource

doesn't have

IngestionSourceExecutionRequests

as a field. @orange-night-91387 do you see any problem if we send a PR to set

generateParameterizedFieldsResolvers

to

false

in

build.gradle

so the response of these parameterized queries can be generated? In our testing, we only need to change

CreateViewResolver.java

because the constructor of

DatahubView

takes one more parameter with this change. FYI, @gray-airplane-39227

I don't think we would have a problem with accepting a PR with this change, we don't use the generated resolver interfaces that come from setting this to true.

Perfect, thank you!