CODEWITHSUNDEEP
graphqlnetflix-dgs
Fellow developer
Fellow developer

Reputation: 11

GraphQl DGS framework does not register data loader class on server startup

I have created a simple graphQL schema as follows,

type Query {
    showsByIds(input: ShowsByIdsInput!
    ) : ShowsByIdsOutput!
}

input ShowsByIdsInput {
    ids: [ID]!
}

type ShowsByIdsOutput {
    ids: [Show!]!
}

type Show @key(fields: "id"){
    id: ID!
    actors: Actor!
}

type Actor {
    name: String!
}

My DataFetcher looks as follows:

@DgsComponent
public class ShowDataFetcher {

  @DgsQuery
  public ShowsByIdsOutput showsByIds(
      @InputArgument final ShowsByIdsInput input) {
    return ShowsByIdsOutput.newBuilder().build();
  }

  @DgsData(parentType = "Show")
  public CompletableFuture<Actor> actors(
      final DgsDataFetchingEnvironment env) {
    final DataLoader<String, Show> dataLoader = env.getDataLoader(
        ActorDataLoader.class);

    final Show test = env.getSource();

    return dataLoader.load(test.getId())
        .thenApply(show -> show.getAtcors());
  }


My Data Loader looks as follows:

@DgsDataLoader(maxBatchSize = 1)
public class ActorDataLoader implements
    MappedBatchLoader<String, Show> {

    @Override
    public CompletionStage<Map<String, Listing>> load(final Set<String> keys) {
        final int cpunt = keys.size();
        return null;
    }
}

The problem is I keep getting error in the data fetcher class while trying to get dataloader from DgsDataFetchingEnvironment. The Data loader class is not registered at application startup which is why I get exception java.lang.NullPointerException: {\n dfe.getDat…s, annotation))\n } must not be null

I am not sure why the dataloader class does not get registered even after using DgsDataLoader annotation.

Upvotes: 1

Views: 794

Answers (1)

Levin Raju
Levin Raju

Reputation: 1

I had the same issue, the dataloader beans were not loaded yet when the DgsDataLoaderProvider bean is initialized. In our case we found a jakarta outdated dependency was causing the issue. Anyways this config would help

 @Component
@RequiredArgsConstructor
public class DataLoadersInitializer implements SmartInitializingSingleton {

  private final DgsDataLoaderProvider provider;

  @Override
  public void afterSingletonsInstantiated() {
    provider.findDataLoaders$graphql_dgs();
  }
}

Upvotes: 0

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