If you’ve ever found yourself staring at your screen for hours on end waiting for some data to come through, this one’s for you.

To set the stage: what is an event loop? Well, it’s basically a fancy way of saying that we have a program running in the background that listens for events (like incoming network packets) and then does something with them when they happen. It’s like having your own personal assistant who sits there all day waiting to take care of any tasks you throw their way.

Now, why event loop polling is so great for network programming in Go. First off, it allows us to handle multiple connections at once without having to worry about blocking or synchronization issues. This means that we can have our program running smoothly and efficiently even when there are a ton of incoming requests coming through.

So how does event loop polling work? Well, let’s take a look at some code:

// Package main is the main package of the program, indicating that this is the entry point of the program.
package main

// Importing necessary packages for the program to run.
import (
	"fmt" // fmt package is used for printing and formatting.
	"net" // net package is used for networking operations.
)

// The main function is the entry point of the program.
func main() {
	// net.Listen function creates a listener for TCP connections on the specified address and port.
	listener, err := net.Listen("tcp", "localhost:8080")
	if err != nil {
		panic(err) // If there is an error, the program will panic and stop.
	}
	defer listener.Close() // defer statement ensures that the listener is closed at the end of the function.

	// Infinite for loop to continuously accept incoming connections.
	for {
		// listener.Accept function accepts an incoming connection and returns a connection object and an error.
		conn, err := listener.Accept()
		if err != nil {
			continue // If there is an error, the program will continue to the next iteration of the loop.
		}

		// go keyword is used to start a new goroutine, which allows for concurrent execution of multiple functions.
		go handleConnection(conn)
	}
}

// handleConnection function is responsible for handling each individual connection.
func handleConnection(conn net.Conn) {
	defer conn.Close() // defer statement ensures that the connection is closed at the end of the function.

	// buf variable is used to store the data received from the connection.
	buf := make([]byte, 1024)

	// Infinite for loop to continuously read data from the connection.
	for {
		// conn.Read function reads data from the connection and stores it in the buf variable.
		n, err := conn.Read(buf)
		if err != nil {
			break // If there is an error, the loop will break and the function will end.
		}

		// Printing the received data.
		fmt.Println("Received", n, "bytes:")
		for _, b := range buf[:n] {
			fmt.Printf("%c", b)
		}
		fmt.Println()
	}
}

In this example, we’re using a simple TCP server to listen for incoming connections on port 8080. Whenever a new connection is accepted, we start a goroutine (a lightweight thread in Go) that handles the data coming through from that connection. The main loop just keeps listening for more connections and starting new goroutines as needed.

So what’s so great about this approach? Well, first off, it allows us to handle multiple connections at once without having to worry about blocking or synchronization issues. This means that we can have our program running smoothly and efficiently even when there are a ton of incoming requests coming through.

But wait isn’t polling inefficient because we’re constantly checking for events? Well, yes… but only if you do it wrong! In Go (and other event-driven languages), the key is to use non-blocking I/O and asynchronous programming techniques that allow us to handle multiple connections without having to wait for each one to finish.

It’s not always the best solution for every problem, but when used correctly it can be incredibly powerful and efficient.