why i send once, but receive twice

[skmygdrs]

server

package main

import (
	"fmt"
	"math/rand"
	"time"

	czmq "github.com/zeromq/goczmq"
)

func main() {
	pubEndpoint := "tcp://*:5556"
	pubSock, err := czmq.NewPub(pubEndpoint)
	if err != nil {
		panic(err)
	}

	defer pubSock.Destroy()
	pubSock.Bind(pubEndpoint)

	for {
		zipcode := rand.Intn(100000)
		temperature := rand.Intn(215) - 85
		relHumidity := rand.Intn(50) + 10

		msg := fmt.Sprintf("%d %d %d", zipcode, temperature, relHumidity)
		err := pubSock.SendFrame([]byte(msg), 0)
		if err != nil {
			panic(err)
		}
		fmt.Println("send", msg)
		time.Sleep(time.Second * 10)
	}
}

client

package main

import (
	"fmt"
	"strconv"
	"strings"

	czmq "github.com/zeromq/goczmq"
)

func main() {

	pubEndpoint := "tcp://127.0.0.1:5556"
	filter := ""

	subSock, err := czmq.NewSub(pubEndpoint, filter)
	if err != nil {
		panic(err)
	}

	defer subSock.Destroy()

	fmt.Printf("Collecting updates from weather server for %s…\n", filter)
	subSock.Connect(pubEndpoint)

	for i := 0; i < 100; i++ {
		msg, _, err := subSock.RecvFrame()
		if err != nil {
			panic(err)
		}
		fmt.Println("recv msg", i, string(msg))
		weatherData := strings.Split(string(msg), " ")
		temperature, err := strconv.ParseInt(weatherData[1], 10, 64)
		fmt.Println("recv temperature", temperature)
	}

}

server output

send 5384 2 27
send 86137 -34 54
send 97726 52 41
send 12079 46 30
send 30493 126 29
send 98981 67 35
send 44885 105 47
send 73749 88 28
send 4384 53 34
send 64547 92 42
send 3616 -11 50
send 25786 -14 36

client output

recv msg 0 54425 55 16
recv temperature 55
recv msg 1 54425 55 16
recv temperature 55
recv msg 2 3300 -31 21
recv temperature -31
recv msg 3 3300 -31 21
recv temperature -31
recv msg 4 28162 64 38
recv temperature 64
recv msg 5 28162 64 38
recv temperature 64

[skmygdrs]

server output send 98081 -43 57 send 84059 -79 28 send 54425 55 16 send 3300 -31 21 send 28162 64 38 send 33274 106 55 send 23237 41 55 send 65466 48 18

client outpub Collecting updates from weather server for … recv msg 0 54425 55 16 recv temperature 55 recv msg 1 54425 55 16 recv temperature 55 recv msg 2 3300 -31 21 recv temperature -31 recv msg 3 3300 -31 21 recv temperature -31 recv msg 4 28162 64 38 recv temperature 64 recv msg 5 28162 64 38 recv temperature 64 recv msg 6 33274 106 55 recv temperature 106 recv msg 7 33274 106 55 recv temperature 106 recv msg 8 23237 41 55 recv temperature 41 recv msg 9 23237 41 55 recv temperature 41 recv msg 10 65466 48 18 recv temperature 48 recv msg 11 65466 48 18 recv temperature 48