add net.LookupHost for dns

selector/dns/dns.go

@@ -3,6 +3,7 @@ package dns
 
 import (
 	"net"
+	"strconv"
 
 	"github.com/micro/go-micro/registry"
 	"github.com/micro/go-micro/selector"
@@ -29,9 +30,36 @@ func (d *dnsSelector) Options() selector.Options {
 }
 
 func (d *dnsSelector) Select(service string, opts ...selector.SelectOption) (selector.Next, error) {
-	_, srv, err := net.LookupSRV(service, "tcp", d.domain)
+	var srv []*net.SRV
+
+	// check if its host:port
+	host, port, err := net.SplitHostPort(service)
+	// not host:port
 	if err != nil {
-		return nil, err
+		// lookup the SRV record
+		_, srvs, err := net.LookupSRV(service, "tcp", d.domain)
+		if err != nil {
+			return nil, err
+		}
+		// set SRV records
+		srv = srvs
+		// got host:port
+	} else {
+		p, _ := strconv.Atoi(port)
+
+		// lookup the A record
+		ips, err := net.LookupHost(host)
+		if err != nil {
+			return nil, err
+		}
+
+		// create SRV records
+		for _, ip := range ips {
+			srv = append(srv, &net.SRV{
+				Target: ip,
+				Port:   uint16(p),
+			})
+		}
 	}
 
 	var nodes []*registry.Node