Fix for cnames see arvancloud#4

Changes taken from issue author

Signed-off-by: Jo De Boeck <[email protected]>

handler.go

@@ -2,7 +2,7 @@ package redis
 
 import (
 	"fmt"
-	// "fmt"
+	"strings"
 	"time"
 
 	"github.com/coredns/coredns/plugin"
@@ -77,7 +77,17 @@ func (redis *Redis) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.M
 
 	switch qtype {
 	case "A":
-		answers, extras = redis.A(qname, z, record)
+		// Having a CNAME excludes A records, add cnames when querying for A records
+		if len(record.CNAME) > 0 {
+			//println("We have a cname in the record")
+			answers2 := make([]dns.RR, 0, 10)
+			extras2 := make([]dns.RR, 0, 10)
+			answers2, extras2 = redis.CNAME(qname, z, record)
+			answers = append(answers, answers2...)
+			extras = append(extras, extras2...)
+		} else {
+			answers, extras = redis.A(qname, z, record)
+		}
 	case "AAAA":
 		answers, extras = redis.AAAA(qname, z, record)
 	case "CNAME":
@@ -106,6 +116,20 @@ func (redis *Redis) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.M
 	m.Answer = append(m.Answer, answers...)
 	m.Extra = append(m.Extra, extras...)
 
+	// If there is a CNAME RR in the answers, solve the alias
+	for _, CNAMERecord := range record.CNAME {
+		println(CNAMERecord.Host)
+		var query = strings.TrimSuffix(CNAMERecord.Host, "."+z.Name)
+		records := redis.get(query, z)
+
+		answersN := make([]dns.RR, 0, 10)
+		extrasN := make([]dns.RR, 0, 10)
+		answersN, extrasN = redis.A(CNAMERecord.Host, z, records)
+		m.Answer = append(m.Answer, answersN...)
+		m.Extra = append(m.Extra, extrasN...)
+
+	}
+
 	state.SizeAndDo(m)
 	m = state.Scrub(m)
 	_ = w.WriteMsg(m)

lookup_test.go

@@ -15,10 +15,10 @@ var zones = []string {
 	"example.com.", "example.net.",
 }
 
-var lookupEntries = [][][]string {
+var lookupEntries = [][][]string{
 	{
 		{"@",
-			"{\"soa\":{\"ttl\":300, \"minttl\":100, \"mbox\":\"hostmaster.example.com.\",\"ns\":\"ns1.example.com.\",\"refresh\":44,\"retry\":55,\"expire\":66}}",
+			"{\"a\":[{\"ttl\":300, \"ip\":\"5.5.5.5\"}], \"soa\":{\"ttl\":300, \"minttl\":100, \"mbox\":\"hostmaster.example.com.\",\"ns\":\"ns1.example.com.\",\"refresh\":44,\"retry\":55,\"expire\":66}}",
 		},
 		{"x",
 			"{\"a\":[{\"ttl\":300, \"ip\":\"1.2.3.4\"},{\"ttl\":300, \"ip\":\"5.6.7.8\"}]," +
@@ -28,7 +28,7 @@ var lookupEntries = [][][]string {
 			"\"mx\":[{\"ttl\":300, \"host\":\"mx1.example.com.\", \"preference\":10},{\"ttl\":300, \"host\":\"mx2.example.com.\", \"preference\":10}]}",
 		},
 		{"y",
-			"{\"cname\":[{\"ttl\":300, \"host\":\"x.example.com.\"}]}",
+			"{\"cname\":[{\"ttl\":300, \"host\":\"example.com.\"}]}",
 		},
 		{"ns1",
 			"{\"a\":[{\"ttl\":300, \"ip\":\"2.2.2.2\"}]}",