How to Log and Handle Errors Properly in Go

Log errors immediately upon detection using log.Printf with the error message and context, then handle them by returning the error to the caller or terminating the program if unrecoverable. For structured logging in production, use the log/slog package to include timestamps and levels.

package main

import (
	"fmt"
	"log"
	"os"
)

func main() {
	file, err := os.Open("data.txt")
	if err != nil {
		log.Printf("failed to open file: %v", err)
		os.Exit(1)
	}
	defer file.Close()
	fmt.Println("File opened successfully")
}

Logging errors means recording what went wrong so you can fix it later, while handling errors means deciding what to do next, like stopping the program or trying again. Think of it like a car dashboard: the warning light logs the problem, and you handling it means pulling over to check the engine. You should always check for errors right after an operation and decide immediately if the program can continue.