Redis-based sequence generation in node.js

node-redis-sequence.js

'use strict';
/*
initialize npm and make sure you add the required dependencies
$ npm init
$ npm install hapi ioredis redlock --save
  }
*/
const Redlock = require('redlock');
const Redis = require('ioredis');
var client1 = new Redis();

var redlock = new Redlock([client1], {
        retryCount: 2,
        retryDelay: 150
    });


function getSequence(key) {
    return client1.incr(key)
}

function getExclusiveSequence(key) {
    var ttl = 1000;
    return redlock.lock('locks:' + key, ttl).then(function(lock) {
        let res = client1.incr(key)
        lock.unlock();
        return res;
    });    
}


const Hapi = require('hapi');

const server = new Hapi.Server();
server.connection({ 
    host: 'localhost', 
    port: 8000 
});

server.route({
    method: 'GET',
    path:'/sequence/{key}', 
    handler: function (request, reply) {
        let key = request.params.key
        return reply(getExclusiveSequence(key)
            .then(function(val) {
                return { 
                    "key": key,
                    sequence: val 
                }
            }));
    }
});

server.start((err) => {

    if (err) {
        throw err;
    }
    console.log('Server running at:', server.info.uri);
});