Fluentd
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Nodejs
The @fluent-org/logger library is used to post records from Node.js applications to Fluentd.
This article explains how to use it.
NOTE: The previous NPM package, fluent-logger has been deprecated in favor of @fluent-org/logger.

Prerequisites

  • Basic knowledge of Node.js and NPM
  • Basic knowledge of Fluentd
  • Node.js 12.0 or higher

Installing Fluentd

Please refer to the following documents to install fluentd:

Modifying the Config File

Configure Fluentd to use the forward input plugin as its data source:
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<source>
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@type forward
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port 24224
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</source>
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<match fluentd.test.**>
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@type stdout
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</match>
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Restart agent after configuring.
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# for rpm/deb only
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$ sudo /etc/init.d/td-agent restart
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# or systemd
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$ sudo systemctl restart td-agent.service
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Using @fluent-org/logger

Obtaining the Most Recent Version

The most recent version of @fluent-org/logger can be found here.

A Sample Application

Here is a sample Express app using @fluent-org/logger:

package.json

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{
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"name": "node-example",
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"version": "0.0.1",
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"dependencies": {
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"express": "^4.16.0",
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"@fluent-org/logger": "^1.0.2"
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}
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}
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Use npm to install dependencies locally:
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$ npm install
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index.js

This is a simple web app:
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const express = require('express');
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const FluentClient = require('@fluent-org/logger').FluentClient;
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const app = express();
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// The 2nd argument can be omitted. Here is a default value for options.
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const logger = new FluentClient('fluentd.test', {
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socket: {
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host: 'localhost',
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port: 24224,
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timeout: 3000, // 3 seconds
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}
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});
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app.get('/', function(request, response) {
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logger.emit('follow', {from: 'userA', to: 'userB'});
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response.send('Hello World!');
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});
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const port = process.env.PORT || 3000;
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app.listen(port, function() {
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console.log("Listening on " + port);
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});
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Run the app and go to http://localhost:3000/ in your browser to send the logs to Fluentd:
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$ node index.js
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The logs should be output to /var/log/td-agent/td-agent.log or the standard output of the Fluentd process via 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 the high-availability configuration for td-agent. This will improve the reliability of data transfer and query performance.

Monitoring

Monitoring Fluentd itself is also important. The article below describes the general monitoring methods for td-agent.
If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is an open-source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.
Last modified 9mo ago