From b904b58de02d91031773e9e951efd295471f064a Mon Sep 17 00:00:00 2001
From: Yousong Zhou <zhouyousong@yunionyun.com>
Date: Thu, 9 Jan 2020 22:21:13 +0800
Subject: [PATCH 1/3] dnsrecords: add helper methods

---
 pkg/compute/models/dnsrecords.go | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/pkg/compute/models/dnsrecords.go b/pkg/compute/models/dnsrecords.go
index 57bd9b9f30..2b03f41fd5 100644
--- a/pkg/compute/models/dnsrecords.go
+++ b/pkg/compute/models/dnsrecords.go
@@ -375,6 +375,26 @@ func (man *SDnsRecordManager) QueryDnsIps(projectId, name, kind string) []*DnsIp
 	return dnsIps
 }
 
+func (rec *SDnsRecord) IsCNAME() bool {
+	return strings.HasPrefix(rec.Records, "CNAME:")
+}
+
+func (rec *SDnsRecord) HasRecordType(typ string) bool {
+	for _, r := range rec.GetInfo() {
+		if strings.HasPrefix(r, typ+":") {
+			return true
+		}
+	}
+	return false
+}
+
+func (rec *SDnsRecord) GetCNAME() string {
+	if !rec.IsCNAME() {
+		panic("not a cname record: " + rec.Records)
+	}
+	return rec.Records[len("CNAME:"):]
+}
+
 func (rec *SDnsRecord) GetInfo() []string {
 	return strings.Split(rec.Records, DNS_RECORDS_SEPARATOR)
 }

From 1c8475437377ad872d28fa1e8923eb5abb16e636 Mon Sep 17 00:00:00 2001
From: Yousong Zhou <zhouyousong@yunionyun.com>
Date: Thu, 9 Jan 2020 21:24:31 +0800
Subject: [PATCH 2/3] dns: prepare for responding with A record of cname value

---
 pkg/dns/dns.go | 53 ++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 15 deletions(-)

diff --git a/pkg/dns/dns.go b/pkg/dns/dns.go
index f4cabe5058..d6e137259b 100644
--- a/pkg/dns/dns.go
+++ b/pkg/dns/dns.go
@@ -319,27 +319,42 @@ func (r *SRegionDNS) Name() string {
 }
 
 func (r *SRegionDNS) queryLocalDnsRecords(req *recordRequest) (recs []msg.Service) {
-	ips := models.DnsRecordManager.QueryDnsIps(req.ProjectId(), req.Name(), req.Type())
-	if len(ips) == 0 {
+	var (
+		projId = req.ProjectId()
+		name   = req.Name()
+		getTtl = func(ttl int) uint32 {
+			if ttl == 0 {
+				return defaultTTL
+			}
+			return uint32(ttl)
+		}
+		rec = models.DnsRecordManager.QueryDns(projId, name)
+	)
+
+	if rec == nil {
 		return
 	}
 
-	for _, ip := range ips {
-		var s = msg.Service{}
-		var ttl uint32 = uint32(ip.Ttl)
-		if ttl == 0 {
-			ttl = defaultTTL
+	var (
+		qtype   = req.Type()
+		pref    = qtype + ":"
+		prefLen = len(pref)
+	)
+	for _, recStr := range rec.GetInfo() {
+		if !strings.HasPrefix(recStr, pref) {
+			continue
 		}
+		val := recStr[prefLen:]
 		if req.IsSRV() {
-			parts := strings.SplitN(ip.Addr, ":", 4)
+			parts := strings.SplitN(val, ":", 4)
 			if len(parts) < 2 {
-				ylog.Errorf("Invalid SRV records: %q", ip.Addr)
+				ylog.Errorf("Invalid SRV records: %q", val)
 				continue
 			}
 			host := parts[0]
 			port, err := strconv.Atoi(parts[1])
 			if err != nil {
-				ylog.Errorf("SRV: invalid port: %s", ip.Addr)
+				ylog.Errorf("SRV: invalid port: %s", val)
 				continue
 			}
 			priority := 0
@@ -348,22 +363,30 @@ func (r *SRegionDNS) queryLocalDnsRecords(req *recordRequest) (recs []msg.Servic
 				var err error
 				weight, err = strconv.Atoi(parts[2])
 				if err != nil {
-					ylog.Errorf("SRV: invalid weight: %s", ip.Addr)
+					ylog.Errorf("SRV: invalid weight: %s", val)
 					continue
 				}
 				if len(parts) >= 4 {
 					priority, err = strconv.Atoi(parts[3])
 					if err != nil {
-						ylog.Errorf("SRV: invalid priority: %s", ip.Addr)
+						ylog.Errorf("SRV: invalid priority: %s", val)
 						continue
 					}
 				}
 			}
-			s = msg.Service{Host: host, Port: port, Weight: weight, Priority: priority, TTL: ttl}
+			recs = append(recs, msg.Service{
+				Host:     host,
+				Port:     port,
+				Weight:   weight,
+				Priority: priority,
+				TTL:      getTtl(rec.Ttl),
+			})
 		} else {
-			s = msg.Service{Host: ip.Addr, TTL: ttl}
+			recs = append(recs, msg.Service{
+				Host: val,
+				TTL:  getTtl(rec.Ttl),
+			})
 		}
-		recs = append(recs, s)
 	}
 	return
 }

From fb9e3c9522644464fecaf3154e911e2fce63524f Mon Sep 17 00:00:00 2001
From: Yousong Zhou <zhouyousong@yunionyun.com>
Date: Thu, 9 Jan 2020 23:18:37 +0800
Subject: [PATCH 3/3] dns: chain load records for cname

---
 pkg/dns/dns.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/pkg/dns/dns.go b/pkg/dns/dns.go
index d6e137259b..a7720bdb9e 100644
--- a/pkg/dns/dns.go
+++ b/pkg/dns/dns.go
@@ -334,6 +334,16 @@ func (r *SRegionDNS) queryLocalDnsRecords(req *recordRequest) (recs []msg.Servic
 	if rec == nil {
 		return
 	}
+	if req.state.QType() != dns.TypeCNAME && rec.IsCNAME() {
+		name = rec.GetCNAME()
+		recs = append(recs, msg.Service{
+			Host: name,
+			TTL:  getTtl(rec.Ttl),
+		})
+		// github.com/coredns/coredns/plugin.{A,AAAA} will call
+		// Services again later for these CNAME
+		return recs
+	}
 
 	var (
 		qtype   = req.Type()