How to gracefully exit a program and handle errors during shutdown in Go?

In Go, you can gracefully exit a program and handle errors during shutdown using a combination of signals, goroutines, and channels. Here's an example:

package main

import (
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"
)

func main() {
	// Create a channel to receive signals
	signals := make(chan os.Signal, 1)
	signal.Notify(signals, os.Interrupt, syscall.SIGTERM)

	// Create a channel to handle shutdown completion
	done := make(chan bool)

	// Start a goroutine to handle shutdown
	go func() {
		// Handle any cleanup tasks before the program exits
		defer fmt.Println("Cleanup tasks...")

		// Perform your shutdown logic here
		time.Sleep(3 * time.Second) // Simulating a cleanup task

		// Notify that shutdown is complete
		done <- true
	}()

	// Wait for the program to exit or receive a shutdown signal
	select {
	case <-done:
		fmt.Println("Graceful shutdown completed")
	case sig := <-signals:
		fmt.Println("Received signal:", sig)
		os.Exit(1)
	}

	// Finish program execution
	fmt.Println("Program exit")
}

In this example:

We create a channel signals to receive signals (e.g., Interrupt or SIGTERM) for graceful shutdown.
We create a channel done for handling shutdown completion.
We start a goroutine to handle shutdown logic. This could include cleanup tasks or any necessary closing of resources.
The shutdown goroutine sends a value to the done channel after the shutdown tasks are completed.
We use a select statement to wait for the done channel to receive a value or the signals channel to receive a signal.
If the program receives a shutdown signal, it prints the signal received and exits with a non-zero status code.
If the program completes the shutdown tasks, it prints a completion message.
Finally, it prints a message indicating the program exit.

By using this approach, you can gracefully exit your program and handle any errors or interruptions during shutdown.