84 lines
2.0 KiB
Go
84 lines
2.0 KiB
Go
//
|
|
// Clone client Model Three
|
|
//
|
|
|
|
package main
|
|
|
|
import (
|
|
zmq "github.com/pebbe/zmq4"
|
|
"github.com/pebbe/zmq4/examples/kvsimple"
|
|
|
|
"fmt"
|
|
"math/rand"
|
|
"time"
|
|
)
|
|
|
|
func main() {
|
|
snapshot, _ := zmq.NewSocket(zmq.DEALER)
|
|
snapshot.Connect("tcp://localhost:5556")
|
|
subscriber, _ := zmq.NewSocket(zmq.SUB)
|
|
subscriber.SetSubscribe("")
|
|
subscriber.Connect("tcp://localhost:5557")
|
|
publisher, _ := zmq.NewSocket(zmq.PUSH)
|
|
publisher.Connect("tcp://localhost:5558")
|
|
|
|
kvmap := make(map[string]*kvsimple.Kvmsg)
|
|
rand.Seed(time.Now().UnixNano())
|
|
|
|
// We first request a state snapshot:
|
|
sequence := int64(0)
|
|
snapshot.SendMessage("ICANHAZ?")
|
|
for {
|
|
kvmsg, err := kvsimple.RecvKvmsg(snapshot)
|
|
if err != nil {
|
|
break // Interrupted
|
|
}
|
|
if key, _ := kvmsg.GetKey(); key == "KTHXBAI" {
|
|
sequence, _ := kvmsg.GetSequence()
|
|
fmt.Println("I: received snapshot =", sequence)
|
|
break // Done
|
|
}
|
|
kvmsg.Store(kvmap)
|
|
}
|
|
snapshot.Close()
|
|
|
|
// Now we wait for updates from the server, and every so often, we
|
|
// send a random key-value update to the server:
|
|
|
|
poller := zmq.NewPoller()
|
|
poller.Add(subscriber, zmq.POLLIN)
|
|
alarm := time.Now().Add(1000 * time.Millisecond)
|
|
for {
|
|
tickless := alarm.Sub(time.Now())
|
|
if tickless < 0 {
|
|
tickless = 0
|
|
}
|
|
polled, err := poller.Poll(tickless)
|
|
if err != nil {
|
|
break // Context has been shut down
|
|
}
|
|
if len(polled) == 1 {
|
|
kvmsg, err := kvsimple.RecvKvmsg(subscriber)
|
|
if err != nil {
|
|
break // Interrupted
|
|
}
|
|
|
|
// Discard out-of-sequence kvmsgs, incl. heartbeats
|
|
if seq, _ := kvmsg.GetSequence(); seq > sequence {
|
|
sequence = seq
|
|
kvmsg.Store(kvmap)
|
|
fmt.Println("I: received update =", sequence)
|
|
}
|
|
}
|
|
// If we timed-out, generate a random kvmsg
|
|
if time.Now().After(alarm) {
|
|
kvmsg := kvsimple.NewKvmsg(0)
|
|
kvmsg.SetKey(fmt.Sprint(rand.Intn(10000)))
|
|
kvmsg.SetBody(fmt.Sprint(rand.Intn(1000000)))
|
|
kvmsg.Send(publisher)
|
|
alarm = time.Now().Add(1000 * time.Millisecond)
|
|
}
|
|
}
|
|
fmt.Printf("Interrupted\n%d messages in\n", sequence)
|
|
}
|