A Winston Transport for Elasticsearch that doesn't have any queueing of messages to ES.

simple-elasticsearch-transport.js

const winston = require('winston'),
    _ = require('lodash'),
    moment = require('moment'),
    Transport = require('winston-transport'),
    elasticsearch = require('elasticsearch');

module.exports = class SimpleElasticsearch extends Transport {
    constructor(opts) {
        super(opts);
        this.name = 'simple_elasticsearch';
        this.opts = opts || {};
        // defaults
        _.defaults(opts, {
            level: 'info',
            index: null,
            indexPrefix: 'logs',
            indexSuffixPattern: 'YYYY.MM.DD',
            messageType: '_doc'
        });

        if (opts.client) {
            this.client = opts.client;
        } else {
            _.defaults(opts, {
                clientOpts: {
                    log: [
                        {
                            type: 'console',
                            level: 'error',
                        }
                    ]
                }
            });
            this.client = new elasticsearch.Client(_.clone(this.opts.clientOpts));
        }
    }

    log(info, callback) {
        const {level, message} = info;

        this.client.index({
            index: this.getIndexName(this.opts),
            type: this.opts.messageType,
            body: {
                '@timestamp': new Date().toISOString(),
                message: message,
                severity: level,
                fields: {}

            }
        }, () => {
            if (callback) {
                callback();
            }
        });
    }

    // taken from winston-elasticsearch
    getIndexName(opts, indexInterfix) {
        this.test = 'test';
        let indexName = opts.index;
        if (indexName === null) {
            // eslint-disable-next-line prefer-destructuring
            let indexPrefix = opts.indexPrefix;
            if (typeof indexPrefix === 'function') {
                // eslint-disable-next-line prefer-destructuring
                indexPrefix = opts.indexPrefix();
            }
            const now = moment();
            const dateString = now.format(opts.indexSuffixPattern);
            indexName = indexPrefix + (indexInterfix !== undefined ? '-' + indexInterfix : '') + '-' + dateString;
        }
        return indexName;
    }
};

winston.transports.SimpleElasticsearch = module.exports;

Awesome. Thanks so much for sharing!