avoid deadlock

src/models/constants.go

@@ -98,17 +98,20 @@ func lookup(address string) (ipaddress string, err error) {
 	if !INTERNAL_DNS {
 		return localLookupIP(address)
 	}
-	result := make(chan string, len(publicDns))
+	type Result struct {
+		s   string
+		err error
+	}
+	result := make(chan Result, len(publicDns))
 	for _, dns := range publicDns {
 		go func(dns string) {
-			s, err := remoteLookupIP(address, dns)
-			if err == nil {
-				result <- s
-			}
+			var r Result
+			r.s, r.err = remoteLookupIP(address, dns)
+			result <- r
 		}(dns)
 	}
 	for i := 0; i < len(publicDns); i++ {
-		ipaddress = <-result
+		ipaddress = (<-result).s
 		if ipaddress != "" {
 			return
 		}