#45 support service name as dns address

bin/build-shadow

@@ -0,0 +1,4 @@
+TAG=$(echo $TRAVIS_BRANCH | sed "s/\//-/")
+TAG=${TAG:-latest}
+docker build -t registry.cn-hangzhou.aliyuncs.com/rdc-incubator/kt-connect-shadow:$TAG -f docker/shadow/Dockerfile .
+docker push registry.cn-hangzhou.aliyuncs.com/rdc-incubator/kt-connect-shadow:$TAG

cmd/proxy/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"os"
 
-	"github.com/alibaba/kt-connect/pkg/proxy/server"
+	"github.com/alibaba/kt-connect/pkg/proxy/daemon"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
 )
@@ -14,8 +14,11 @@ func init() {
 }
 
 func main() {
-	err := server.Run()
+	log.Info().Msg("Start kt connect proxy")
+	srv := daemon.NewDNSServerDefault()
+	err := srv.ListenAndServe()
 	if err != nil {
 		panic(err.Error())
 	}
+	log.Info().Msgf("DNS Server Start At 53...\n")
 }

go.sum

@@ -146,6 +146,7 @@ golang.org/x/oauth2 v0.0.0-20190402181905-9f3314589c9a h1:tImsplftrFpALCYumobsd0
 golang.org/x/oauth2 v0.0.0-20190402181905-9f3314589c9a/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20170830134202-bb24a47a89ea/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=

pkg/proxy/daemon/dnsserver.go

@@ -51,14 +51,12 @@ func getDomain(origin string) string {
 		namespace = "default"
 	}
 
-	index := strings.Index(domain, ".")
-
-	if index+1 == len(domain) {
+	if !strings.Contains(domain, ".svc.cluster.local.") {
 		domain = domain + namespace + ".svc.cluster.local."
 		log.Info().Msgf("*** Use in cluster dns address %s\n", domain)
 	}
-	log.Info().Msgf("Format domain %s to %s\n", origin, domain)
 
+	log.Info().Msgf("Format domain %s to %s\n", origin, domain)
 	return domain
 }
 
@@ -68,18 +66,16 @@ func query(w dns.ResponseWriter, req *dns.Msg) (rr []dns.RR) {
 		return
 	}
 
+	msg := new(dns.Msg)
+	msg.RecursionDesired = true
+
 	qtype := req.Question[0].Qtype
 	name := req.Question[0].Name
-
 	domain := getDomain(name)
-
-	log.Info().Msgf("Received DNS query for %s: \n", domain)
 
-	msg := new(dns.Msg)
+	log.Info().Msgf("Received DNS query for %s: \n", domain)
 	msg.SetQuestion(domain, qtype)
-	msg.RecursionDesired = true
-
-	rr = exchange(domain, qtype, msg)
+	rr = exchange(domain, qtype, msg, name)
 	return
 }
 
@@ -98,7 +94,7 @@ func getResolvServer() (address string, err error) {
 	return
 }
 
-func exchange(domain string, Qtype uint16, m *dns.Msg) (rr []dns.RR) {
+func exchange(domain string, Qtype uint16, m *dns.Msg, name string) (rr []dns.RR) {
 	address, err := getResolvServer()
 	if err != nil {
 		log.Error().Msgf(err.Error())
@@ -119,6 +115,36 @@ func exchange(domain string, Qtype uint16, m *dns.Msg) (rr []dns.RR) {
 		return
 	}
 
-	rr = res.Answer
+	for _, item := range res.Answer {
+		log.Info().Msgf("response: %s", item.String())
+		r, err := getAnswer(name, domain, item)
+		if err != nil {
+			return	
+		}
+		rr = append(rr, r)
+	}
+
+	return
+}
+
+func getAnswer(name string, inClusterName string, acutal dns.RR) (tmp dns.RR, err error) {
+	var parts []string
+	if name != inClusterName {
+		log.Info().Msgf("origin %s query name is not same %s", inClusterName, name)
+		parts = append(parts, name)
+
+		log.Info().Msgf("origin answer rr to %s", acutal.String())
+		answer := strings.Split(acutal.String(), "\t")
+
+		parts = append(parts, answer[1:]...)
+		rrStr := strings.Join(parts, " ")
+		log.Info().Msgf("rewrite rr to %s", rrStr)
+		tmp, err = dns.NewRR(rrStr)
+		if err != nil {
+			return
+		}
+	} else {
+		tmp = acutal
+	}
 	return
 }

pkg/proxy/daemon/dnsserver_test.go

@@ -0,0 +1,18 @@
+package daemon
+
+import (
+	"testing"
+	"github.com/miekg/dns"
+)
+
+func TestAnswerRewrite(t *testing.T) {
+	acutal, _ := dns.NewRR("tomcat.default.svc.cluster.local. 5 IN A 172.21.4.129")
+	r, err := getAnswer("tomcat.", "tomcat.default.svc.cluster.local.", acutal)
+	if err != nil {
+		t.Errorf("error")
+		return
+	}
+	if r.String() != "tomcat.	5	IN	A	172.21.4.129" {
+		t.Errorf("error")
+	}
+}