Fluentd
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 document to install Fluentd:
Modifying the Config File
Configure Fluentd to use the forward input plugin as its data source:
<source>
@type forward
port 24224
</source>
<match fluentd.test.**>
@type stdout
</match>
Restart Fluentd after configuring.
# for fluent-package (rpm/deb)
$ sudo systemctl restart fluentd
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
{
"name": "node-example",
"version": "0.0.1",
"dependencies": {
"express": "^4.16.0",
"@fluent-org/logger": "^1.0.2"
}
}
Use npm to install dependencies locally:
$ npm install
index.js
This is a simple web app:
const express = require('express');
const FluentClient = require('@fluent-org/logger').FluentClient;
const app = express();
// The 2nd argument can be omitted. Here is a default value for options.
const logger = new FluentClient('fluentd.test', {
socket: {
host: 'localhost',
port: 24224,
timeout: 3000, // 3 seconds
}
});
app.get('/', function(request, response) {
logger.emit('follow', {from: 'userA', to: 'userB'});
response.send('Hello World!');
});
const port = process.env.PORT || 3000;
app.listen(port, function() {
console.log("Listening on " + port);
});
Run the app and go to http://localhost:3000/ in your browser to send the logs to Fluentd:
$ node index.js
The logs should be output to /var/log/fluent/fluentd.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:
- Examples
- List of Plugin References
High-Availability Configurations of Fluentd
For high-traffic websites (more than 5 application nodes), we recommend using the high-availability configuration for Fluentd. 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 Fluentd.