What is Seq?

Seq is a modern log management solution that helps developers collect, explore, and analyze their logs in real-time. It allows you to centralize your logs from various sources and provides powerful querying capabilities that make troubleshooting and debugging a breeze.

Prerequisites

To follow along with this tutorial, you will need:

• Node.js installed on your development machine
• A Seq instance (self-hosted or cloud) with the necessary API key

Installation

To install the Seq client package in your Node.js application, run the following command:

npm install @datalust/seq

Usage

Once you have installed the Seq client package, you can start logging events from your Node.js application. First, require the Seq package and create a new instance:

const Seq = require('@datalust/seq');

const seqLogger = new Seq.Logger({
  serverUrl: 'https://your-seq-instance.com',
  apiKey: 'your-api-key',
});

Replace https://your-seq-instance.com with the URL of your Seq instance and 'your-api-key' with your actual API key.

Logging events

To log an event with Seq, you can use the log method provided by the Seq logger instance:

seqLogger.log({
  level: 'Information',
  message: 'User logged in',
  properties: {
    username: 'john.doe',
    ipAddress: '192.168.0.1',
  },
});

In the above example, we are logging an event with a level of ‘Information’ and a custom message. We can also include additional properties as an object, which can be useful for logging contextual information.

Enhancing logs with structured data

Seq shines when it comes to structured logging. Instead of formatting log messages as plain text, you can provide structured data in the form of JSON objects. This makes it easier to search, filter, and analyze logs later on.

Here’s an example of logging a structured event:

seqLogger.log({
  level: 'Error',
  message: 'Database connection failed',
  properties: {
    error: {
      name: 'ConnectionError',
      message: 'Unable to connect to the database',
    },
    tags: ['database', 'connection'],
  },
});

In this case, we are logging an error event and including an error object and a ‘tags’ property. These additional properties can be helpful for advanced log analysis.

Summary

Implementing real-time logging with Seq in Node.js applications is a powerful way to gain insights into your application’s behavior. By leveraging the rich set of features provided by Seq, you can streamline your logging workflow and easily troubleshoot issues. Remember to strategically log events and take advantage of structured logging to make the most out of your logs.

Start monitoring your Node.js applications with Seq today and take your logging to the next level! #Seq #NodejsLogging