gateway.js

const { ApolloServer } = require('apollo-server')
const { ApolloGateway } = require('@apollo/gateway')
const { post } = require('httpie')

async function getSupergraph() {
  const res = await post(`http://localhost:3000/schema/supergraph`, {
    body: {
      graphName: 'my_graph',
    },
  })

  return {
    supergraphSdl: res.data.data.supergraphSdl,
    id: res.data.data.compositionId,
  }
}

async function startServer() {
  const gateway = new ApolloGateway({
    // fetch for schema or service updates every 30s
    experimental_pollInterval: 30000,

    async experimental_updateSupergraphSdl() {
      return getSupergraph()
    },

    // Experimental: Enabling this enables the query plan view in Playground.
    __exposeQueryPlanExperimental: false,
  })

  const server = new ApolloServer({
    gateway,

    // Apollo Graph Manager (previously known as Apollo Engine)
    // When enabled and an `ENGINE_API_KEY` is set in the environment,
    // provides metrics, schema management and trace reporting.
    engine: false,

    // Subscriptions are unsupported but planned for a future Gateway version.
    subscriptions: false,
  })

  server.listen().then(({ url }) => {
    console.log(`🚀 Server ready at ${url}`)
  })
}

startServer().catch((err) => {
  console.error(err)
  process.exit(1)
})