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push_receiver.go
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/
push_receiver.go
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/*
* Copyright 1999-2020 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package naming_client
import (
"bytes"
"compress/gzip"
"encoding/json"
"io/ioutil"
"math/rand"
"net"
"strconv"
"time"
"github.com/wubin1989/nacos-sdk-go/common/logger"
"github.com/wubin1989/nacos-sdk-go/util"
)
type PushReceiver struct {
port int
host string
hostReactor *HostReactor
}
type PushData struct {
PushType string `json:"type"`
Data string `json:"data"`
LastRefTime int64 `json:"lastRefTime"`
}
var (
GZIP_MAGIC = []byte("\x1F\x8B")
)
func NewPushReceiver(hostReactor *HostReactor) *PushReceiver {
pr := PushReceiver{
hostReactor: hostReactor,
}
pr.startServer()
return &pr
}
func (us *PushReceiver) tryListen() (*net.UDPConn, bool) {
addr, err := net.ResolveUDPAddr("udp", us.host+":"+strconv.Itoa(us.port))
if err != nil {
logger.Errorf("can't resolve address,err: %+v", err)
return nil, false
}
conn, err := net.ListenUDP("udp", addr)
if err != nil {
logger.Errorf("error listening %s:%d,err:%+v", us.host, us.port, err)
return nil, false
}
return conn, true
}
func (us *PushReceiver) getConn() *net.UDPConn {
for i := 0; i < 3; i++ {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
port := r.Intn(1000) + 54951
us.port = port
conn, ok := us.tryListen()
if ok {
logger.Infof("udp server start, port: " + strconv.Itoa(port))
return conn
}
if !ok && i == 2 {
logger.Errorf("failed to start udp server after trying 3 times.")
}
}
return nil
}
func (us *PushReceiver) startServer() {
conn := us.getConn()
if conn == nil {
return
}
go func() {
defer conn.Close()
for {
us.handleClient(conn)
}
}()
}
func (us *PushReceiver) handleClient(conn *net.UDPConn) {
if conn == nil {
time.Sleep(time.Second * 5)
conn = us.getConn()
if conn == nil {
return
}
}
data := make([]byte, 4024)
n, remoteAddr, err := conn.ReadFromUDP(data)
if err != nil {
logger.Errorf("failed to read UDP msg because of %+v", err)
return
}
s := TryDecompressData(data[:n])
logger.Info("receive push: "+s+" from: ", remoteAddr)
var pushData PushData
err1 := json.Unmarshal([]byte(s), &pushData)
if err1 != nil {
logger.Infof("failed to process push data.err:%+v", err1)
return
}
ack := make(map[string]string)
if pushData.PushType == "dom" || pushData.PushType == "service" {
us.hostReactor.ProcessServiceJson(pushData.Data)
ack["type"] = "push-ack"
ack["lastRefTime"] = strconv.FormatInt(pushData.LastRefTime, 10)
ack["data"] = ""
} else if pushData.PushType == "dump" {
ack["type"] = "dump-ack"
ack["lastRefTime"] = strconv.FormatInt(pushData.LastRefTime, 10)
ack["data"] = util.ToJsonString(us.hostReactor.serviceInfoMap)
} else {
ack["type"] = "unknow-ack"
ack["lastRefTime"] = strconv.FormatInt(pushData.LastRefTime, 10)
ack["data"] = ""
}
bs, _ := json.Marshal(ack)
c, err := conn.WriteToUDP(bs, remoteAddr)
if err != nil {
logger.Errorf("WriteToUDP failed,return:%d,err:%+v", c, err)
}
}
func TryDecompressData(data []byte) string {
if !IsGzipFile(data) {
return string(data)
}
reader, err := gzip.NewReader(bytes.NewReader(data))
if err != nil {
logger.Errorf("failed to decompress gzip data,err:%+v", err)
return ""
}
defer reader.Close()
bs, err := ioutil.ReadAll(reader)
if err != nil {
logger.Errorf("failed to decompress gzip data,err:%+v", err)
return ""
}
return string(bs)
}
func IsGzipFile(data []byte) bool {
if len(data) < 2 {
return false
}
return bytes.HasPrefix(data, GZIP_MAGIC)
}