GQL - Multi Tenant Idea

mt.js

const tenantsConfig = [
  { name: 't1', connStr: 'mongodb://...' },
  { name: 't2', connStr: 'mongodb://...' }
];

let tenantConns = tenantsConfig.map(tenant => ({
  ...tenant,
  conn: mongoose.createConnection(tenant.connStr))
});
                                    
let tenantModels = tenantConns.map(tenant => ({
  ...tenant,
  models: createModels(tenant.conn) // see below
}));

let tenantGqlSchemas = tenantModels.map(tenant => ({
  ...tenant,
  gqlSchema: createGQLSchema(tenant.models) // see below
})).reduce((map, tenant) => {
  return {
    ...map,
    [tenant.name]: tenant.gqlSchema
  }
}, {});

// When setting up the GQL api endpint (Assuming express-graphql)
app.use('/graphql', graphqlHTTP(req => ({
  schema: tenantGqlSchemas[getTenantNameFromRequest(req)].gqlSchema,
  graphiql: process.env.NODE_ENV !== 'production',
  pretty: process.env.NODE_ENV !== 'production',
})));

// Somewhere else
import { ComposeStorage  } from 'graphql-compose'; 
import composeWithMongoose from 'graphql-compose-mongoose';
import { composeWithRelay } from 'graphql-compose-relay';
import UserSchema from './Schemas/User';
import DogSchema from './Schemas/Dog';
const createModels = (conn) => {
  let UserModel = conn.model('User', UserSchema);
  let DogModel = conn.model('Dog', DogSchema);
  return {
    user: UserModel,
    dog: DogModel
  }
}

const createGQLSchema = (models) => {
  const GQC = new ComposeStorage(); // Don't want to reuse the GQC storage - this allows creating a new one.
  const userTC = composeWithRelay(composeWithMongoose(models.user));
  const dogTC = composeWithRelay(composeWithMongoose(models.dog));
  return GQC.rootQuery().addFields({
    user: userTC.get('$findById'),
    dog: dogTC.get('$findById')
    //... more
  }).buildSchema();
}