Integrate this project in already existing gqlgen project

[frederikhors]

I'm sorry for this question, I'm still learning GraphQL and Golang world.

I'm using gqlgen (https://github.com/99designs/gqlgen) to generate my own GraphQL server.

I need to "merge" other private/custom schemas to my own.

But I don't want to start two different services (my own gqlgen server and nautilus/gateway) to do so.

Is there a way to "integrate", in the same Golang project, gqlgen generated server and this amazing gateway?

In this way I can reduce a lot the network requests: there would be only those for "external" schemas.

What do you think of my idea?

[frederikhors]

I already have a:

var gql = handler.GraphQL(graphql.NewExecutableSchema(graphql.Config{Resolvers: &graphql.Resolver{}}), config.GraphqlHandlerOptions)

It would be amazing to use that graphql.NewExecutableSchema coming from gqlgen.

[edwinmo-splunk]

Hey @frederikhors! We actually had this exact use case and came up with a way to not have to host two separate services and still utilize the Nautilus gateway. We accomplished this by writing our own Queryer that will resolve the query using the gqlgen executable schema. It looks roughly like this:

func (self *customQueryer) Query(ctx context.Context, input *graphqlGW.QueryInput, receiver interface{}) error {
	// ignore the input.QueryDocument as it seems that Nautilus is not constructing it correctly
	// instead, rely on the input.Query like how gqlgen wrote their handler
	doc, gqlErr := parser.ParseQuery(&ast.Source{Input: input.Query})
	if gqlErr != nil {
		return gqlErr
	}

	// more validation stuff; this is REQUIRED and not just a validation step
	// it changes the `*ast.Schema` that is required for gqlgen to execute it
	if listErr := validator.Validate(self.executableSchema.Schema(), doc); len(listErr) != 0 {
		return fmt.Errorf("Error validating query with schema %+v", listErr)
	}

	requestContext := graphql.NewRequestContext(doc, input.Query, input.Variables)
	newCtx := graphql.WithRequestContext(ctx, requestContext)
	operationDefinition := doc.Operations.ForName(input.OperationName)

	var response *graphql.Response
	if operationDefinition.Operation == ast.Mutation {
		response = self.executableSchema.Mutation(newCtx, operationDefinition)
	} else {
		response = self.executableSchema.Query(newCtx, operationDefinition)
	}

	responseBytes, err := response.Data.MarshalJSON()
	if err != nil {
		return err
	}

	err = json.Unmarshal(responseBytes, receiver)
	if err != nil {
		return err
	}

	return nil
}

Here, self.executableSchema is the result from calling graphql.NewExecutableSchema coming from gqlgen.

You'll need to provide a QueryerFactory.

I hope this was helpful.