sha256server.go

package main

import (
	"crypto/sha256"
	"fmt"
	"io"
	"log"
	"net"
	"sync/atomic"
	"time"
)

var (
	conns uint64
	pkts  uint64
)

func printStatistics() {
	started := time.Now().Unix()
	for {
		time.Sleep(5 * time.Second)
		cs := atomic.LoadUint64(&conns)
		ps := atomic.LoadUint64(&pkts)
		delta := uint64(time.Now().Unix() - started)
		fmt.Printf("conn: %v, pkt: %v, time: %v\n%v pkts/s\n", cs, ps, delta, ps/delta)
	}
}

func main() {
	go printStatistics()
	ln, err := net.Listen("tcp", ":9090")
	if err != nil {
		log.Fatal(err)
	}

	for {
		if conn, err := ln.Accept(); err == nil {
			go handleConn(conn)
		}
	}
}

func handleConn(conn net.Conn) {
	defer conn.Close()
	atomic.AddUint64(&conns, 1)

	buf := make([]byte, 512)
	for {
		if _, err := io.ReadFull(conn, buf); err != nil {
			return
		}
		atomic.AddUint64(&pkts, 1)

		if _, err := fmt.Fprintf(conn, "%X", sha256.Sum256(buf)); err != nil {
			return
		}
	}
}