echo.go

package main

import (
        "bufio"
        "fmt"
        "io"
        "log"
        "net"
        "time"
)

func main() {
        log.SetFlags(log.LstdFlags | log.Lmicroseconds)
        listener, err := net.Listen("tcp", ":8080")
        if err != nil {
                log.Fatalf("Failed to listen: %v", err)
        }
        defer listener.Close()
        log.Printf("TCP Echo Server listening on :8080 at epoch ms: %d", time.Now().UnixMilli())
        for {
                conn, err := listener.Accept()
                if err != nil {
                        log.Printf("Failed to accept connection: %v", err)
                        continue
                }
                go handleConnection(conn)
        }
}

func handleConnection(conn net.Conn) {
        defer conn.Close()
        remoteAddr := conn.RemoteAddr().String()
        log.Printf("New connection from %s at epoch ms: %d", remoteAddr, time.Now().UnixMilli())
        reader := bufio.NewReader(conn)
        for {
                data, err := reader.ReadString('\n')
                if err != nil {
                        if err != io.EOF {
                                log.Printf("Error reading from connection: %v", err)
                        }
                        return
                }
                nowMs := time.Now().UnixMilli()
                fmt.Printf("[%d] From %s: %s", nowMs, remoteAddr, data)
                _, err = conn.Write([]byte(data))
                if err != nil {
                        log.Printf("Error writing to connection: %v", err)
                        return
                }
        }
}