Graphql Remote Schema Stitching TS

gralphql.ts

import { readFileSync } from 'fs';

import { mergeSchemas, makeExecutableSchema } from 'graphql-tools';
import { getRemoteSchemas } from './remoteSchemas';
import { Resolvers } from './resolvers';

export const createSchema = async () => {
  const resolvers = [Resolvers];

  const localSchema = readFileSync(require.resolve('./schema.gql'), 'utf8');
  const remoteSchemas = await Promise.all(Object.values(getRemoteSchemas()));

  return mergeSchemas({
    schemas: [...remoteSchemas, localSchema],
    resolvers
  });
};

remoteSchemas.ts

import {
  makeRemoteExecutableSchema,
  introspectSchema,
  transformSchema,
  FilterRootFields
} from 'graphql-tools';
import config from 'config';
import { HttpLink } from 'apollo-link-http';
import fetch from 'node-fetch';

const tripsServiceUrl = config.get<string>('services.trips');

const fetchSchema = async (uri: string) => {
  const link = new HttpLink({ uri, fetch });
  const schema = await makeRemoteExecutableSchema({
    schema: await introspectSchema(link),
    link
  });
  // Remove all query/mutations from the schema -- we only care about the types
  return transformSchema(schema, [new FilterRootFields(() => false)]);
};

export const getRemoteSchemas = () => ({
  trips: fetchSchema(tripsServiceUrl) // No schema stitching with trips service for now
});