graceful-shutdown-rest-graphql.js

const express = require('express');
const { ApolloServer, gql } = require('apollo-server-express');

const app = express();
app.get('/', async  (req, res) => {
    await new Promise(resolve => setTimeout(resolve, 5000));
    res.send('ok');
});

const typeDefs = gql`
    type Query {
        hello: String
    }
`;
const resolvers = {
  Query: {
    hello: async () => {
        await new Promise(resolve => setTimeout(resolve, 5000));
        return 'Hello world!'
    },
  },
};
const apollo = new ApolloServer({ typeDefs, resolvers });
apollo.applyMiddleware({ app });

const server = app.listen(3000);
server.keepAliveTimeout = 1;

const sockets = [];
server.on('connection', socket => {
    sockets.push(socket);
    socket.on('close', () => sockets.splice(sockets.indexOf(socket), 1));
});

process.on('SIGINT', async () => {
    await server.close();
    await apollo.stop();
    while(sockets.length !== 0) {
        console.log(`sockets: ${sockets.length}`);
        await new Promise(resolve => setTimeout(resolve, 100));
    }
});