timesync
This commit is contained in:
parent
a56731085d
commit
c4098de5b4
@ -6,7 +6,9 @@ import (
|
||||
"log"
|
||||
"net"
|
||||
"os"
|
||||
"sync"
|
||||
"time"
|
||||
"strings"
|
||||
)
|
||||
|
||||
func scanError(scanResult []string, conn net.Conn) {
|
||||
@ -15,17 +17,104 @@ func scanError(scanResult []string, conn net.Conn) {
|
||||
}
|
||||
}
|
||||
|
||||
type timeExchange struct {
|
||||
before, after, remote int64
|
||||
}
|
||||
|
||||
type client struct {
|
||||
timeExchange
|
||||
id int
|
||||
addr string
|
||||
}
|
||||
|
||||
func remotef(host, command, format string, args ...interface{}) (int, error) {
|
||||
connection, err := net.Dial("tcp", host)
|
||||
if err != nil {
|
||||
return 0, fmt.Errorf("remotef: establishing connection: %v", err)
|
||||
}
|
||||
defer connection.Close()
|
||||
connection.SetDeadline(time.Now().Add(1 * time.Second))
|
||||
|
||||
fmt.Fprintln(connection, command)
|
||||
if len(format) > 0 {
|
||||
parsedCount, err := fmt.Fscanf(connection, format, args...)
|
||||
if err != nil {
|
||||
return 0, fmt.Errorf("remotef: parsing: %v", err)
|
||||
}
|
||||
return parsedCount, nil
|
||||
}
|
||||
|
||||
return 0, nil
|
||||
}
|
||||
|
||||
func (e *timeExchange) estimateFor(host string) bool {
|
||||
e.before = time.Now().UnixMilli()
|
||||
parsedCount, err := remotef(host, "time", "%d\n", &e.remote)
|
||||
e.after = time.Now().UnixMilli()
|
||||
|
||||
if err != nil {
|
||||
log.Println("estimateFor: %v", err)
|
||||
return false
|
||||
}
|
||||
if parsedCount != 1 {
|
||||
log.Printf("berkeley: expected to parse number, instead parsed %d items\n", parsedCount)
|
||||
return false
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
func timesync(hosts []string) []client {
|
||||
wg := sync.WaitGroup{}
|
||||
wg.Add(len(hosts))
|
||||
|
||||
// Gather time from each host
|
||||
responses := make(chan client, len(hosts))
|
||||
for id, host := range hosts {
|
||||
id, host := id, host
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
exchange := timeExchange{};
|
||||
if exchange.estimateFor(host) {
|
||||
responses <- client{exchange, id, host}
|
||||
}
|
||||
}()
|
||||
}
|
||||
|
||||
wg.Wait()
|
||||
close(responses)
|
||||
|
||||
clients := make([]client, 0, len(hosts))
|
||||
for client := range responses {
|
||||
clients = append(clients, client)
|
||||
}
|
||||
return clients
|
||||
}
|
||||
|
||||
const maxReactionTime = 300
|
||||
|
||||
func notifyAll(clients []client) {
|
||||
wg := sync.WaitGroup{}
|
||||
wg.Add(len(clients))
|
||||
startDeadline := time.After(maxReactionTime * time.Millisecond)
|
||||
|
||||
for _, client := range clients {
|
||||
client := client
|
||||
go func() {
|
||||
myTime := time.Now().UnixMilli()
|
||||
startTime := myTime + maxReactionTime - (client.remote - client.before) + (client.after - client.before) / 2
|
||||
_, err := remotef(client.addr, fmt.Sprintf("start %d", startTime), "")
|
||||
if err != nil {
|
||||
log.Printf("failed to notify %s: %v\n", client.addr, err)
|
||||
}
|
||||
wg.Done()
|
||||
}()
|
||||
}
|
||||
|
||||
<-startDeadline
|
||||
return
|
||||
}
|
||||
|
||||
func main() {
|
||||
|
||||
// HTTP part
|
||||
// fileServer := http.FileServer(http.Dir("./static"))
|
||||
// http.Handle("/", fileServer)
|
||||
// http.HandleFunc("/cmd", cmdHandler)
|
||||
// http.HandleFunc("/scan", scanHandler)
|
||||
|
||||
// http.HandleFunc("/hello", helloHandler)
|
||||
|
||||
// TCP part
|
||||
l, err := net.Listen("tcp", ":8081")
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
@ -38,21 +127,19 @@ func main() {
|
||||
}
|
||||
go func(c net.Conn) {
|
||||
s := bufio.NewScanner(c)
|
||||
conn.Write([]byte("> "))
|
||||
var scanResult []string
|
||||
var clients []client
|
||||
for s.Scan() {
|
||||
resp := s.Text()
|
||||
if resp == "scan" {
|
||||
conn.Write([]byte("Scanning...\n"))
|
||||
scanResult = scan()
|
||||
conn.Write([]byte("Scanning done!\n"))
|
||||
conn.Write([]byte("> "))
|
||||
fmt.Println(len(scanResult))
|
||||
continue
|
||||
}
|
||||
if resp == "time" {
|
||||
conn.Write([]byte(showTime().String() + "\n"))
|
||||
conn.Write([]byte("> "))
|
||||
fmt.Fprintln(conn, time.Now().UnixMilli())
|
||||
continue
|
||||
}
|
||||
if resp == "hosts" {
|
||||
@ -61,67 +148,39 @@ func main() {
|
||||
conn.Write([]byte(host + "\n"))
|
||||
fmt.Println("CONNECTED")
|
||||
}
|
||||
conn.Write([]byte("> "))
|
||||
continue
|
||||
}
|
||||
if resp == "showtime" {
|
||||
cTime := showTime()
|
||||
conn.Write([]byte(cTime.String() + "\n"))
|
||||
continue
|
||||
}
|
||||
|
||||
if resp == "timesync" {
|
||||
time.Sleep(1 * time.Second)
|
||||
conn.Write([]byte("Server time: " + time.Now().String() + "\n"))
|
||||
scanError(scanResult, conn)
|
||||
for _, host := range scanResult {
|
||||
if host == "" {
|
||||
fmt.Print("No host")
|
||||
}
|
||||
fmt.Println(host)
|
||||
conn.Write([]byte("Waiting for time from " + host + "\n"))
|
||||
outconn, err := net.Dial("tcp", host)
|
||||
if err != nil {
|
||||
fmt.Println(err)
|
||||
os.Exit(1)
|
||||
}
|
||||
defer outconn.Close()
|
||||
recvBuf := make([]byte, 1024)
|
||||
msg := []byte("showtime\n")
|
||||
n, err2 := outconn.Write(msg)
|
||||
if n != len(msg) {
|
||||
fmt.Println("didn't send all the bytes")
|
||||
os.Exit(1)
|
||||
}
|
||||
if err2 != nil {
|
||||
fmt.Println(err)
|
||||
os.Exit(1)
|
||||
}
|
||||
// Temporary fix, fixme pls
|
||||
var read int
|
||||
for {
|
||||
var err3 error
|
||||
read, err3 = outconn.Read(recvBuf)
|
||||
if read > 2 {
|
||||
break
|
||||
}
|
||||
if err3 != nil {
|
||||
fmt.Println(err)
|
||||
os.Exit(1)
|
||||
}
|
||||
}
|
||||
_, err4 := conn.Write(recvBuf)
|
||||
if err4 != nil {
|
||||
fmt.Println(err)
|
||||
os.Exit(1)
|
||||
}
|
||||
outconn.Close()
|
||||
clients = timesync(scanResult)
|
||||
continue
|
||||
}
|
||||
if strings.HasPrefix(resp, "start") {
|
||||
startTimeString := strings.TrimSpace(resp[len("start"):])
|
||||
startTime := int64(0)
|
||||
fmt.Scanf(startTimeString, "%d", &startTime)
|
||||
currentTime := time.Now().UnixMilli()
|
||||
if currentTime > startTime {
|
||||
log.Println("cannot start after given time")
|
||||
continue
|
||||
}
|
||||
time.Sleep(time.Duration(startTime - currentTime) * time.Millisecond)
|
||||
log.Println("Started #start")
|
||||
continue
|
||||
}
|
||||
if resp == "notify" {
|
||||
notifyAll(clients)
|
||||
log.Println("Started #notify")
|
||||
continue
|
||||
}
|
||||
if resp == "quit" {
|
||||
c.Close()
|
||||
os.Exit(0)
|
||||
}
|
||||
conn.Write([]byte("> "))
|
||||
}
|
||||
c.Close()
|
||||
}(conn)
|
||||
|
@ -8,8 +8,6 @@ import (
|
||||
)
|
||||
|
||||
func scan() []string {
|
||||
var information []string
|
||||
|
||||
var wg sync.WaitGroup
|
||||
ips := make(chan string, 256)
|
||||
|
||||
@ -28,9 +26,10 @@ func scan() []string {
|
||||
copy(localIP, ipv4)
|
||||
wg.Add(1)
|
||||
go func(ip net.IP) {
|
||||
_, dialErr := net.DialTimeout("tcp", ip.String()+":8081", time.Duration(1)*time.Second)
|
||||
conn, dialErr := net.DialTimeout("tcp", ip.String()+":8081", time.Duration(1)*time.Second)
|
||||
if dialErr == nil {
|
||||
ips <- ip.String() + ":8081"
|
||||
conn.Close()
|
||||
}
|
||||
wg.Done()
|
||||
}(localIP)
|
||||
@ -45,10 +44,10 @@ func scan() []string {
|
||||
close(ips)
|
||||
}()
|
||||
|
||||
information := []string{}
|
||||
for ip := range ips {
|
||||
fmt.Println("Response from " + ip)
|
||||
information = append(information, ip)
|
||||
}
|
||||
|
||||
return information
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user