Data Import from Node.js Applications

The ‘fluent-logger-node’ library is used to post records from Node.js applications to Fluentd.

This article explains how to use the fluent-logger-node library.

Table of Contents


  • Basic knowledge of Node.js and NPM
  • Basic knowledge of Fluentd
  • Node.js 0.6 or higher

Installing Fluentd

Please refer to the following documents to install fluentd.

Modifying the Config File

Next, please configure Fluentd to use the forward Input plugin as its data source.

  type forward
  port 24224
<match fluentd.test.**>
  type stdout

Please restart your agent once these lines are in place.

# for rpm/deb only
$ sudo /etc/init.d/td-agent restart

Using fluent-logger-node

Obtaining the Most Recent Version

The most recent version of fluent-logger-node can be found here.

A Sample Application

A sample Express app using fluent-logger-node is shown below.


  "name": "node-example",
  "version": "0.0.1",
  "dependencies": {
    "express": "2.5.9",
    "fluent-logger": "0.1.0"

Now use npm to install your dependencies locally:

$ npm install
fluent-logger@0.1.0 ./node_modules/fluent-logger
express@2.5.9 ./node_modules/express
|-- qs@0.4.2
|-- mime@1.2.4
|-- mkdirp@0.3.0
|-- connect@1.8.6 (formidable@1.0.9)


This is the simplest web app.

var express = require('express');
var app = express.createServer(express.logger());

var logger = require('fluent-logger');
logger.configure('fluentd.test', {host: 'localhost', port: 24224});

app.get('/', function(request, response) {
  logger.emit('follow', {from: 'userA', to: 'userB'});
  response.send('Hello World!');
var port = process.env.PORT || 3000;
app.listen(port, function() {
  console.log("Listening on " + port);

Execute the app and go to http://localhost:3000/ in your browser. This will send the logs to Fluentd.

$ node web.js

The logs should be output to /var/log/td-agent/td-agent.log or stdout of the Fluentd process via the stdout Output plugin.

Production Deployments

Output Plugins

Various output plugins are available for writing records to other destinations:

High-Availability Configurations of Fluentd

For high-traffic websites (more than 5 application nodes), we recommend using a high availability configuration of td-agent. This will improve data transfer reliability and query performance.


Monitoring Fluentd itself is also important. The article below describes general monitoring methods for td-agent.

Last updated: 2016-06-06 04:47:13 UTC

If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is a open source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.