slogs

README

slogs

This is a wrapper around the stdlib Golang slog package that just creates a slog logger in some standard way, with a configurable log level.

Slog was introduced in Go 1.21, so that is the minimum required Go version to use this module.

Usage

package main

import "github.com/chia-network/go-modules/pkg/slogs"

func main() {
	// Init the logger with a log-level string (debug, info, warn, error)
	// defaults to "info" if empty or unsupported string 
	slogs.Init("info")
	
	// Logs a hello world message at the info level
	slogs.Logr.Info("hello world")
	
	// Logs an error message at the error level 
	slogs.Logr.Error("we received an error")
}

In a Cobra/Viper CLI app this might look more like:

package cmd

import (
	"log"
	
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"github.com/chia-network/go-modules/pkg/slogs"
)

var rootCmd = &cobra.Command{
	Use:   "cmd",
	Short: "Short help message for cmd",

	Run: func(cmd *cobra.Command, args []string) {
		// Init logger
		slogs.Init(viper.GetString("log-level"))

		// Application logic below
	},
}

func Execute() {
	cobra.CheckErr(rootCmd.Execute())
}

func init() {
	rootCmd.PersistentFlags().String("log-level", "info", "The log-level for the application, can be one of info, warn, error, debug.")
	err := viper.BindPFlag("log-level", rootCmd.PersistentFlags().Lookup("log-level"))
	if err != nil {
		log.Fatalln(err.Error()) // Have to log with standard logger until the slog logger is initialized
	}
}

Documentation

Index

• func Init(level string)
• type Logger
  • func (l Logger) Fatal(msg string, args ...any)

Functions

func Init

func Init(level string)

Init custom init function that accepts the log level for the application and initializes a stdout slog logger

Types

type Logger

type Logger struct {
	*slog.Logger
}

Logger is a wrapper around the slog logger struct so we can have a type that is owned by this scope to create additional wrapper functions around

var Logr Logger

Logr is a custom text logger from the stdlib slog package

func (Logger) Fatal

func (l Logger) Fatal(msg string, args ...any)

Fatal is a wrapper around the standard slog Error function that exits 1 after it is called. Similar to the stdlib log.Fatal function