graphql sequlize dataloader issue, Cannot return null for non-nullable field

Question

schema for ip address:

import { gql } from 'apollo-server-express';

module.exports = gql`
    extend type Query {
        # allTxn: [SubscrTxn]
        cblockIp(ip_key: Int!): CblockIp
    }

    type CblockIp {
        ip_key: Int!
        ip_address: String
        cblock_key: Int!
    }
`;

I've created a data-loader but I get "errors":

[
    {
      "message": "Cannot return null for non-nullable field ConfigProxy.ip_key.",

if I require the field ip_key: CblockIp! And if I remove the "!" from ip_key: CblockIp the ip_key is null :)

{
  "data": {
    "config": {
      "config_name": "FF0RFQH0",
      "configProxy": [
        {
          "proxy_key": 4351701,
          "ip_key": null
        },
        {
          "proxy_key": 4351702,
          "ip_key": null
        },
        {
          "proxy_key": 4351703,
          "ip_key": null
        },
        {
          "proxy_key": 4351700,
          "ip_key": null
        }
      ]
    }
  }
}

My files look like this:

app.js part of it:

import DataLoader from 'dataloader';
import { proxyBatcher } from './batchFunctions';

const server = new ApolloServer({
    typeDefs,
    resolvers,
    context: ({ req }) => ({
        models,
        secret: process.env.JWT_SECRET,
        member: getLoggedInUser(req),
        me: getLoggedInUser(req),
        proxyLoader: new DataLoader((keys) => proxyBatcher(keys, models))
    })
});

batchFunctions.js:

import _ from 'lodash';
import { Op } from 'sequelize';

export const proxyBatcher = async (keys, { CblockIp }) => {
    const proxies = await CblockIp.findAll({
        raw: true,
        where: {
            ip_key: {
                [Op.in]: keys
            }
        }
    });

    const gp = _.groupBy(proxies, 'ip_key');
    console.log(proxies);
    console.log(gp);
    console.log(keys.map((k) => gp[k] || []));

    return keys.map((k) => gp[k] || []);
};

export const dummy = 5;

configProxy.js (resolver) :

import { requiresAuth } from '../permissions';

const resolvers = {
    Query: {
        // configs: (parent, args, { models }) => {
        //  return models.Config.findAll();
        // },
        configProxy: requiresAuth.createResolver(
            (parent, { proxy_key }, { models }) => {
                return models.ConfigProxy.findOne({
                    where: {
                        proxy_key
                    }
                });
            }
        )
    },
    ConfigProxy: {
        config_key: (parent, args, { models }) => {
            return models.Config.findByPk(parent.config_key);
        },
        ip_key: (parent, args, { proxyLoader }) => {
            proxyLoader.load(parent.ip_key);
            //return models.CblockIp.findByPk(parent.ip_key)
        }
    }
};

if in my resolver i replace { proxyLoader } with { models } and this line

proxyLoader.load(parent.ip_key);

with

return models.CblockIp.findByPk(parent.ip_key)

everything is working, but without batcher. I suppose in my batcher I'm doing something wrong.

Console.log shows that everything should be fine even in batcher that's why I don't understand where the problem is. Here is the console.log from batcher function of :

console.log(proxies);
console.log(gp);
console.log(keys.map((k) => gp[k] || []));

Executing (default): SELECT `config_key`, `config_type`, `config_name`, `filename`, `member_key`, `proxy_port` FROM `config` AS `config` WHERE `config`.`config_key` = 2314;
Executing (default): SELECT `proxy_key`, `config_key`, `ip_key` FROM `config_proxy` AS `config_proxy` WHERE `config_proxy`.`config_key` = 2314;
Executing (default): SELECT `ip_key`, `ip_address`, `cblock_key` FROM `cblock_ip` AS `cblock_ip` WHERE `cblock_ip`.`ip_key` IN (116312, 185667, 185969, 99424);
[ { ip_key: 99424, ip_address: '172.246.69.152', cblock_key: 576 },
  { ip_key: 116312, ip_address: '45.59.24.113', cblock_key: 645 },
  { ip_key: 185667,
    ip_address: '184.174.74.121',
    cblock_key: 1051 },
  { ip_key: 185969,
    ip_address: '184.174.75.170',
    cblock_key: 1052 } ]
{ '99424':
   [ { ip_key: 99424, ip_address: '172.246.69.152', cblock_key: 576 } ],
  '116312':
   [ { ip_key: 116312, ip_address: '45.59.24.113', cblock_key: 645 } ],
  '185667':
   [ { ip_key: 185667,
       ip_address: '184.174.74.121',
       cblock_key: 1051 } ],
  '185969':
   [ { ip_key: 185969,
       ip_address: '184.174.75.170',
       cblock_key: 1052 } ] }
[ [ { ip_key: 116312, ip_address: '45.59.24.113', cblock_key: 645 } ],
  [ { ip_key: 185667,
      ip_address: '184.174.74.121',
      cblock_key: 1051 } ],
  [ { ip_key: 185969,
      ip_address: '184.174.75.170',
      cblock_key: 1052 } ],
  [ { ip_key: 99424, ip_address: '172.246.69.152', cblock_key: 576 } ] ]

and the graphql query looks like this

query Proxies($config_key: Int!) {
  config(config_key: $config_key) {
    config_name
    configProxy {
      proxy_key
      ip_key {
        ip_address
      }
    }
  }
}

Answer 1

You're not returning anything inside your resolver.

return proxyLoader.load(parent.ip_key);