Graphql-tools: Stitcher does not work in [email protected]

[abhishek199-dhn]

Issue:
I'm trying to stitch multiple remote schemas together, but it does not work with [email protected]. It seems that Introspection request query is not formed properly. It gives 400 Bad request. This works for [email protected]

 getIntrospectSchema: async (uri) => {

        // Fetch schema
        try {
            const fetcher = createApolloFetch({uri});
            fetcher.use(({request, options}, next) => {
                if (!options.headers) {
                    options.headers = {};
                }
                next();
            });

            return makeRemoteExecutableSchema({
                schema: await introspectSchema(fetcher),
                fetcher,
            });

        } catch (e) {
            console.error(`[getIntrospectSchema] Introspection failed for ${uri} \n Stackstrace: ${e}`);
            return Promise.resolve();
        }
    }

const endpoints = ["http://localhost:3000/graphql"];
const remoteSchema = await Promise.all(endpoints.map(ep => introspection.getIntrospectSchema(ep)));
const mergedSchema = mergeSchemas({schemas: remoteSchema});


const server = new ApolloServer({schema: mergedSchema});
registerServer({server, app});

// normal ApolloServer listen call but url will contain /graphql
server.listen().then(({url}) => {
   Logger.info("Node app is running on port", app.get("port"));
});

Package used:-
"apollo-fetch": "^0.7.0",
"apollo-server": "^2.0.0-beta.1",
"apollo-server-express": "^2.0.0-beta.0",
"express": "~4.16.0",
"graphql": "^0.13.2",
"graphql-tools": "3.0.1"

Repo link - Graphql Stitcher

[luandro]

I've also been trying to get it to work, but not even the Launchpad example is working.

Update: Was a problem with my project, got it to work.

[matthew-gordon]

Not working for me either, Launch Pad example not working either.

[RobertStigsson]

I'm fairly sure you can solve it by just adding an empty resolver-object. mergeSchemas doesn't seem to work without a resolver-object:
https://launchpad.graphql.com/zrl387xpv7

[matthew-gordon]

Thanks @RobertStigsson, I gave that a go, still no luck, just receiving an internal server error and still getting the same "Expected [object Promise] to be a GraphQL schema. Updated code...

import {
  mergeSchemas,
  introspectSchema,
  makeRemoteExecutableSchema,
} from 'graphql-tools';
import { createApolloFetch } from 'apollo-fetch';
// import { HttpLink } from 'apollo-link-http';
// import fetch from 'node-fetch';

async function makeMergedSchema() {
  const createRemoteSchema = async (uri) => {
    const fetcher = createApolloFetch({ uri });
    return makeRemoteExecutableSchema({
      schema: await introspectSchema(fetcher),
      fetcher,
    });
  };

  const UserSchema = await createRemoteSchema('http://users-service:3000/api/graphql');
  const MoviesSchema = await createRemoteSchema('http://movies-service:3000/api/graphql');
  const schema = mergeSchemas({
    schemas: [UserSchema, MoviesSchema],
    resolvers: {},
  });

  return schema;
}

const schema = makeMergedSchema();

export default schema;

[RobertStigsson]

matthew-gordon, the whole empty resolver thing seems to be a thing of the past. It makes launchpads work with 2.x, but with 3.x it works without the resolver functions.

I don't know why your solution doesn't work with apollo-fetch, but maybe it isn't updated to work with 3.x (or maybe, since I've never used apollo-fetch, I'm just not good enough at it to understand the issue)?

My suggestion is, at least for now, use HttpLink instead, which I see that you've already tried once. Here is an example with your code (other remoteSchemas) and HttpLink:

https://launchpad.graphql.com/554wr4j339

[matthew-gordon]

Thanks again @RobertStigsson, but still a no go, must be something with the way I have Docker configured.. found an article here ARTICLE that I'll try to implement.

[abhishek199-dhn]

@RobertStigsson thanks.!!
Using HttpLink instead of createApolloFetch works well with [email protected]. But I have to find a way to set custom headers.

const fetcher = new HttpLink({uri: url, fetch});
 return makeRemoteExecutableSchema({
            schema: await introspectSchema(fetcher),
            link: fetcher,
 });

[matthew-gordon]

Alright, I solved my issue, it indeed was a networking issue with Docker.

here's my working implementation following along with this Article

import Koa from 'koa';
import Router from 'koa-router';
import bodyParser from 'koa-bodyparser';
import logger from 'koa-logger';
import { graphqlKoa, graphiqlKoa } from 'apollo-server-koa';
import { mergeSchemas } from 'graphql-tools';
import { getIntrospectSchema } from './introspection';

const app = new Koa();
const router = new Router();
const HOST = '0.0.0.0';
const PORT = process.env.PORT || 3000;

// our graphql endpoints
const endpoints = [
  'http://users-service:3000/graphql',
  'http://movies-service:3000/graphql',
];

app.use(logger());
app.use(bodyParser());

router.get('/', (ctx) => {
  ctx.body = {
    message: 'Gateway Service',
  };
});

(async function () {
  try {
    // promise.all to grab all remote schemas at the same time
    const allSchemas = await Promise.all(endpoints.map(ep => getIntrospectSchema(ep)));

    // create function for /graphql endpoint and merge all the schemas
    router.get('/graphql', graphqlKoa(() => ({
      schema: mergeSchemas({ schemas: allSchemas }),
    })));

    router.get('/graphiql', graphiqlKoa({
      endpointURL: '/graphql',
    }));

    router.post('/graphql', graphqlKoa(() => ({
      schema: mergeSchemas({ schemas: allSchemas }),
    })));

    // start up a graphql endpoint for our main server
  } catch (error) {
    console.log('ERROR: Failed to grab introspection queries', error);
  }
}());

app.use(router.routes());
app.use(router.allowedMethods());
app.listen(PORT, HOST);
console.log(`Listening on http://${HOST}:${PORT}...`);

introspection.js

const fetch = require('node-fetch');
const { makeRemoteExecutableSchema, introspectSchema } = require('graphql-tools');
const { createHttpLink } = require('apollo-link-http');

module.exports = {
  getIntrospectSchema: async (url) => {
    // Create a link to a GraphQL instance by passing fetch instance and url
    const makeDatabaseServiceLink = () => createHttpLink({
      uri: url,
      fetch,
    });

    // Fetch our schema
    const databaseServiceSchemaDefinition = await introspectSchema(makeDatabaseServiceLink());

    // make an executable schema
    return makeRemoteExecutableSchema({
      schema: databaseServiceSchemaDefinition,
      link: makeDatabaseServiceLink(),
    });
  },
};

docker-compose.yml

version: "3"

services:
  users-service:
    build: ./services/users
    ports:
      - 3000:3000
  movies-service:
    build: ./services/movies
    ports:
      - 3001:3000
    depends_on:
      - users-service
  gateway-service:
    build: ./services/gateway
    ports:
      - 3002:3000
    depends_on:
      - users-service
      - movies-service
    links:
      - users-service
      - movies-service

[RobertStigsson]

@abhishek199-dhn no problems, glad to be able to help.

In order to set customer headers, use setContext from apollo-link-context:

const { setContext } = require('apollo-link-context')

const fetcher = new HttpLink({uri: url, fetch});

const fetcherWithContext = setContext((request, previousContext) => ({
    headers: {
      Authentication: `Bearer ${previousContext.bearerToken}`
    }
  })).concat(fetcher)

[abhishek199-dhn]

@RobertStigsson thanks!!