Effective Logging with log/slog in Go Projects

Introduction

In Go language project development, efficient log searching and filtering are crucial for debugging. However, the standard library’s “log” package does not provide structured logging, making it less convenient. In Go 1.21.0, a new structured logging package, “log/slog,” was introduced to address this issue. It supports key-value pair formatting. This article will explore how to use “log/slog.”

Usage of log/slog

The default logger of “log/slog” utilizes the default logger of the “log” package, making it easy to get started. “log/slog” defines four log levels: Info, Debug, Warn, and Error, each with corresponding functions.

Example:

func main() {
     log.Println("This is log")
     slog.Debug("This is Debug Level")
     slog.Info("This is Info Level")
     slog.Warn("This is Warn Level")
     slog.Error("This is Error Level")
 }

Output:

2023/10/06 11:18:04 This is log
 2023/10/06 11:18:04 INFO This is Info Level
 2023/10/06 11:18:04 WARN This is Warn Level
 2023/10/06 11:18:04 ERROR This is Error Level

In the code above, you’ll notice that the output of “log/slog” is very similar to “log,” with the addition of log levels between the timestamp and log message. This is because “log/slog” uses the default logger of “log.”

Apart from the four log level functions, there is also a “log” function that…