refactor: Waiting for network connection when dns exception (#1057)

dns/index.go

@@ -4,7 +4,6 @@ import (
 	"time"
 
 	"github.com/jeessy2/ddns-go/v6/config"
-	"github.com/jeessy2/ddns-go/v6/dns/internet"
 	"github.com/jeessy2/ddns-go/v6/util"
 )
 
@@ -16,7 +15,7 @@ type DNS interface {
 }
 
 var (
-	addresses = []string{
+	Addresses = []string{
 		alidnsEndpoint,
 		baiduEndpoint,
 		zonesAPI,
@@ -35,8 +34,6 @@ var (
 
 // RunTimer 定时运行
 func RunTimer(delay time.Duration) {
-	internet.Wait(addresses)
-
 	for {
 		RunOnce()
 		time.Sleep(delay)

main.go

@@ -51,7 +51,7 @@ var noWebService = flag.Bool("noweb", false, "No web service")
 var skipVerify = flag.Bool("skipVerify", false, "Skip certificate verification")
 
 // 自定义 DNS 服务器
-var customDNSServer = flag.String("dns", "", "Custom DNS server, example: 8.8.8.8")
+var customDNS = flag.String("dns", "", "Custom DNS server, example: 8.8.8.8")
 
 //go:embed static
 var staticEmbeddedFiles embed.FS
@@ -83,8 +83,8 @@ func main() {
 	if *skipVerify {
 		util.SetInsecureSkipVerify()
 	}
-	if *customDNSServer != "" {
-		util.SetDNS(*customDNSServer)
+	if *customDNS != "" {
+		util.SetDNS(*customDNS)
 	}
 	os.Setenv(util.IPCacheTimesENV, strconv.Itoa(*ipCacheTimes))
 	switch *serviceType {
@@ -136,6 +136,12 @@ func run() {
 		}()
 	}
 
+	// 初始化默认DNS
+	util.InitDefaultDNS(*customDNS, conf.Lang)
+
+	// 等待网络连接
+	util.WaitInternet(dns.Addresses)
+
 	// 定时运行
 	dns.RunTimer(time.Duration(*every) * time.Second)
 }
@@ -221,8 +227,8 @@ func getService() service.Service {
 		svcConfig.Arguments = append(svcConfig.Arguments, "-skipVerify")
 	}
 
-	if *customDNSServer != "" {
-		svcConfig.Arguments = append(svcConfig.Arguments, "-dns", *customDNSServer)
+	if *customDNS != "" {
+		svcConfig.Arguments = append(svcConfig.Arguments, "-dns", *customDNS)
 	}
 
 	prg := &program{}

util/net_resolver.go

@@ -3,8 +3,27 @@ package util
 import (
 	"context"
 	"net"
+
+	"golang.org/x/text/language"
 )
 
+// dnsList is a list of DNS servers.
+var DNSList = []string{}
+
+func InitDefaultDNS(customDNS, lang string) {
+	if customDNS != "" {
+		DNSList = []string{customDNS}
+		return
+	}
+
+	if lang == language.Chinese.String() {
+		DNSList = []string{"223.5.5.5", "114.114.114.114"}
+		return
+	}
+
+	DNSList = []string{"1.1.1.1", "8.8.8.8"}
+}
+
 // SetDNS sets the dialer.Resolver to use the given DNS server.
 func SetDNS(dns string) {
 	// Error means that the given DNS doesn't have a port. Add it.

util/wait_internet.go

@@ -0,0 +1,44 @@
+package util
+
+import (
+	"math/rand"
+	"strings"
+	"time"
+)
+
+// Wait blocks until the Internet is connected.
+//
+// See also:
+//
+//   - https://stackoverflow.com/a/50058255
+//   - https://github.com/ddev/ddev/blob/v1.22.7/pkg/globalconfig/global_config.go#L776
+func WaitInternet(addresses []string) {
+	delay := time.Second * 5
+
+	for {
+		for _, addr := range addresses {
+
+			err := LookupHost(addr)
+			// Internet is connected.
+			if err == nil {
+				return
+			}
+
+			Log("等待网络连接: %s", err)
+			Log("%s 后重试...", delay)
+
+			if isDNSErr(err) && len(DNSList) > 0 {
+				dns := DNSList[rand.Intn(len(DNSList))]
+				Log("本机DNS异常! 将默认使用 %s, 可参考文档通过 -dns 自定义 DNS 服务器", dns)
+				SetDNS(dns)
+			}
+
+			time.Sleep(delay)
+		}
+	}
+}
+
+// isDNSErr checks if the error is caused by DNS.
+func isDNSErr(e error) bool {
+	return strings.Contains(e.Error(), "[::1]:53: read: connection refused")
+}