Distributed PHP sessions using memcached extension and coreos/etcd (PoC)

sesscache.go

package main

import (
	"bufio"
	"fmt"
	"net"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"time"

	"github.com/coreos/go-etcd/etcd"
)

var ETCD = []string{"http://127.0.0.1:4001"}

func main() {
	runtime.GOMAXPROCS(4)

	kv := etcd.NewClient(ETCD)
	ok := kv.SyncCluster()
	if !ok {
		panic("Cannot connect to etcd")
	}
	kv.Close()

	ln, err := net.Listen("tcp", "127.0.0.1:11211")
	for i := 0; err == nil; i++ {
		var conn net.Conn
		conn, err = ln.Accept()
		go handleConnection(conn, i)
	}

}

func handleConnection(conn net.Conn, i int) {
	defer conn.Close()

	kv := etcd.NewClient(ETCD)
	duration := 0
	kv.SetDialTimeout(time.Duration(duration) * time.Millisecond)
	defer kv.Close()

	//fmt.Printf("%d: %v <-> %v\n", i, conn.LocalAddr(), conn.RemoteAddr())

	b := bufio.NewReader(conn)
	for {
		line, err := b.ReadBytes('\n')
		if err != nil {
			break
		}

		switch {
		case strings.HasPrefix(string(line), "get "):
			handleGetCommand(conn, i, kv, line)
		case strings.HasPrefix(string(line), "set "):
			handleSetCommand(conn, i, kv, line, b)
		case strings.HasPrefix(string(line), "delete "):
			handleDeleteCommand(conn, i, kv, line)
		case string(line) == "quit\r\n":
			conn.Close()
		case string(line) == "stats\r\n":
			conn.Write([]byte("END\r\n"))
		case string(line) == "version\r\n":
			conn.Write([]byte("VERSION 1.4.22\r\n"))
		default:
			fmt.Printf("%d: %v: %v", i, "Unknown command", string(line))
			conn.Write([]byte("ERROR\r\n"))
		}
	}

	//fmt.Printf("%d: closed\n", i)
}

func handleGetCommand(conn net.Conn, i int, kv *etcd.Client, line []byte) bool {
	re := regexp.MustCompile(`^(get)\s(.*\w+)(?:\r\n)$`)
	matches := re.FindAllString(string(line), -1)
	if matches == nil {
		//fmt.Printf("%d: %v\r\n", i, "CLIENT_ERROR (GET) bad command line format")
		conn.Write([]byte("CLIENT_ERROR GET bad command line format\r\n"))
		return false
	}

	items := strings.Fields(matches[0])
	key := "/sesscache/" + items[1]

	resp, err := kv.Get(key, false, false)
	if err != nil {
		conn.Write([]byte("END\r\n"))
		return true
	}

	reply := fmt.Sprintf("VALUE %v 0 %d\r\n%v\r\nEND\r\n", items[1], len(resp.Node.Value), resp.Node.Value)
	conn.Write([]byte(reply))
	return true
}

func handleSetCommand(conn net.Conn, i int, kv *etcd.Client, line []byte, b *bufio.Reader) bool {
	re := regexp.MustCompile(`^(set|add|replace)\s(.*\w+)\s([0-9]{1,})\s([0-9]{1,})\s([0-9]{1,})\s?([a-zA-Z0-9]\w+)?(?:\r\n)$`)
	matches := re.FindAllString(string(line), -1)
	if matches == nil {
		//fmt.Printf("%d: %v\r\n", i, "CLIENT_ERROR (SET1) bad command line format")
		conn.Write([]byte("CLIENT_ERROR bad command line format\r\n"))
		return false
	}

	items := strings.Fields(matches[0])
	key := "/sesscache/" + items[1]

	ttt, _ := strconv.Atoi(items[3])
	ttl := uint64(ttt)

	bytes, _ := strconv.Atoi(items[4])

	//b := bufio.NewReader(conn)
	line2, err := b.ReadBytes('\n')
	if err != nil {
		return false
	}

	re2 := regexp.MustCompile(`^(.*)(?:\r\n)$`)
	matches2 := re2.FindAllString(string(line2), -1)
	if matches2 == nil {
		//fmt.Printf("%d: %v\r\n", i, "CLIENT_ERROR (SET2) bad command line format")
		conn.Write([]byte("CLIENT_ERROR bad command line format\r\n"))
		return false
	}

	items2 := strings.Fields(matches2[0])
	value := string(items2[0])

	if len(value) != bytes {
		//fmt.Printf("%d: %v\r\n", i, "CLIENT_ERROR bad data chunk")
		conn.Write([]byte("CLIENT_ERROR bad bad data chunk\r\n"))
		return false
	}

	if _, err := kv.Set(key, value, ttl); err != nil {
		//fmt.Printf("%d: %v: %v", i, "SERVER_ERROR", err)
		conn.Write([]byte("SERVER_ERROR ...\r\n"))
		return false
	}
	conn.Write([]byte("STORED\r\n"))
	return true
}

func handleDeleteCommand(conn net.Conn, i int, kv *etcd.Client, line []byte) bool {
	re := regexp.MustCompile(`^(delete)\s(.*\w+)\s?([a-zA-Z0-9]\w+)?(?:\r\n)$`)
	matches := re.FindAllString(string(line), -1)
	if matches == nil {
		//fmt.Printf("%d: %v", i, "CLIENT_ERROR (DELETE) bad command line format")
		conn.Write([]byte("CLIENT_ERROR bad command line format\r\n"))
		return false
	}

	items := strings.Fields(matches[0])
	key := "/sesscache/" + items[1]

	_, err := kv.Delete(key, false)
	if err != nil {
		conn.Write([]byte("NOT_FOUND\r\n"))
		return true
	}

	conn.Write([]byte("DELETED\r\n"))
	return true
}