Schema issues with Apollo Server 4 Managed (Apollo Studio), Apollo Gateway and Subscriptions

[CorrieP]

Hi There

I have the following setup:

import { ApolloServer } from '@apollo/server';
import { ApolloGateway } from '@apollo/gateway';
import { expressMiddleware } from '@apollo/server/express4';
import { ApolloServerPluginDrainHttpServer } from '@apollo/server/plugin/drainHttpServer';
import { ApolloServerPluginSubscriptionCallback } from '@apollo/server/plugin/subscriptionCallback';
import express from 'express';
import http from 'http';
import { WebSocketServer } from 'ws';
import { useServer } from 'graphql-ws/lib/use/ws';
import cors from 'cors';
import * as dotenv from 'dotenv';

async function startServer() {

  const app = express();
  const httpServer = http.createServer(app);

  const gateway = new ApolloGateway({
    uplinkMaxRetries: 3,
    fallbackPollIntervalInMs: 60000
  });

  const wsServer = new WebSocketServer({
    server: httpServer,
    path: '/graphql',
  });

// THIS gateway.schema is empty?

  const serverCleanup = useServer(
    {
      schema: gateway.schema
    },
    wsServer
  );

  const server = new ApolloServer({
    gateway,
    plugins: [
      ApolloServerPluginSubscriptionCallback(),
      ApolloServerPluginDrainHttpServer({ httpServer }),
      {
        async serverWillStart() {
          return {
            async drainServer() {
              await serverCleanup.dispose();
            },
          };
        },
      },
    ],
  });

  await server.start();

  app.use(
    '/graphql',
    cors<cors.CorsRequest>(),
    express.json(),
    expressMiddleware(server, {
      context: async ({ req }) => ({ 
        token: req.headers.token 
      }),
    }),
  );

  const PORT = process.env.PORT || 4700;
  httpServer.listen(PORT, () => {
    console.log(`🚀 Query endpoint ready at http://localhost:${PORT}/graphql`);
    console.log(`🚀 Subscription endpoint ready at ws://localhost:${PORT}/graphql`);
  });

  // Requests to `http://localhost:4700/health` now return "Okay!"
  app.get('/health', (req, res) => {
    res.status(200).send('Okay!');
  });

}

startServer().catch((error) => {
  console.error('Failed to start the server:', error);
  process.exit(1);
});

The server starts up but when I try to execute I get this error:

Internal error occurred during message handling. Please check your implementation. Error: The GraphQL schema is not provided

So is there a way to get the schema from Apollo Studio (Managed Environment)
so that when I hook up the websockets it knows what the graphql schema is?

Thank you.