Display error rate when inserting MQTT data into ES

error_rate.js

const mqtt = require('mqtt');
const ES = require('esta');

const INDEX = 'mqtt',
    TYPE = 'eclipse';

let counter = 0,
    errors = 0;

ES.CONNECT(INDEX, () => {
    const client = mqtt.connect('mqtt://iot.eclipse.org');

    client.on('connect', () => {
        client.subscribe('#');
    });

    client.on('message', (topic, message) => {
        if (counter > 5000) {
            client.end(true);
            console.log(`Error rate : ${(errors / counter) * 100}%`);
            console.log(`Error count : ${errors}`);
            process.exit();
        }
        addARecord(message.toString(), topic);
    });
});

function addARecord(message, topic) {
    const record = {
        index: INDEX,
        type: TYPE,
        date: new Date().toISOString(),
        message: message,
        topic: topic
    };
    ES.CREATE(record, function (response) {
        counter++;
        // Check if data has been inserted properly
        if (response.created === undefined) {
            errors++;
        }
    });
}

process.on('uncaughtException', function (err) {
    console.log('ERROR: ' + err);
});

We try to insert 5000 messages and check the error rate of the insertion, most of the time it is NOT zero.