fix dns client date race

Signed-off-by: ii2day <ji.li@daocloud.io>

pkg/loadRequest/loadDns/dns_requester.go

@@ -25,12 +25,14 @@
 package loadDns
 
 import (
+	"context"
 	"crypto/tls"
 	"github.com/kdoctor-io/kdoctor/pkg/k8s/apis/system/v1beta1"
 	"github.com/kdoctor-io/kdoctor/pkg/utils/stats"
 	"github.com/miekg/dns"
 	"go.uber.org/zap"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"net"
 	"sync"
 	"time"
 )
@@ -142,12 +144,22 @@ func (b *Work) Finish() {
 	b.report.finalize(total)
 }
 
-func (b *Work) makeRequest(client *dns.Client, conn *dns.Conn, wg *sync.WaitGroup) {
+func (b *Work) makeRequest(conn *dns.Conn, wg *sync.WaitGroup) {
 	defer wg.Done()
 	var msg *dns.Msg
 	var rtt time.Duration
 	var err error
 
+	client := new(dns.Client)
+	client.Net = b.Protocol
+	client.Timeout = time.Duration(b.Timeout) * time.Millisecond
+	if b.Protocol == "tcp-tls" {
+		tlsConfig := &tls.Config{
+			InsecureSkipVerify: true,
+		}
+		client.TLSConfig = tlsConfig
+	}
+
 	if b.Protocol == "tcp" || b.Protocol == "tcp-tls" {
 		msg, rtt, err = client.Exchange(b.Msg, b.ServerAddr)
 
@@ -166,15 +178,10 @@ func (b *Work) makeRequest(client *dns.Client, conn *dns.Conn, wg *sync.WaitGrou
 }
 
 func (b *Work) runWorker() {
-	client := new(dns.Client)
-	client.Net = b.Protocol
-	client.Timeout = time.Duration(b.Timeout) * time.Millisecond
-	conn, _ := client.Dial(b.ServerAddr)
-	if b.Protocol == "tcp-tls" {
-		tlsConfig := &tls.Config{
-			InsecureSkipVerify: true,
-		}
-		client.TLSConfig = tlsConfig
+	conn, err := b.makeConn()
+	if err != nil {
+		b.Logger.Sugar().Errorf("failed create dns conn,err=%v", err)
+		return
 	}
 	wg := &sync.WaitGroup{}
 	for {
@@ -185,7 +192,7 @@ func (b *Work) runWorker() {
 			return
 		case <-b.qosTokenBucket:
 			wg.Add(1)
-			go b.makeRequest(client, conn, wg)
+			go b.makeRequest(conn, wg)
 		}
 	}
 }
@@ -250,3 +257,12 @@ func (b *Work) AggregateMetric() *v1beta1.DNSMetrics {
 
 	return metric
 }
+
+func (b *Work) makeConn() (*dns.Conn, error) {
+	var err error
+	d := net.Dialer{Timeout: time.Duration(b.Timeout) * time.Millisecond}
+	conn := new(dns.Conn)
+	conn.Conn, err = d.DialContext(context.Background(), "udp", b.ServerAddr)
+
+	return conn, err
+}