Issue #8 Use maininterface instead for Hyper-V

pkg/crc/services/dns/dns_windows.go

@@ -1,6 +1,7 @@
 package dns
 
 import (
+	"bufio"
 	"fmt"
 	"strings"
 	"time"
@@ -12,17 +13,15 @@ import (
 )
 
 func runPostStartForOS(serviceConfig services.ServicePostStartConfig, result *services.ServicePostStartResult) (services.ServicePostStartResult, error) {
-	// NOTE: this is very Hyper-V specific
-	// TODO: localize the use of the Default Switch
-	setDNSServerCommand := fmt.Sprintf(`Set-DnsClientServerAddress "vEthernet (Default Switch)" -ServerAddress ("%s")`, serviceConfig.IP)
-	powershell.ExecuteAsAdmin(setDNSServerCommand)
+	mainInterface := getMainInterface()
+	serverAddresses := getInterfaceNameserverValues(mainInterface)
+	serverAddresses = append([]string{serviceConfig.IP}, serverAddresses...)
 
-	time.Sleep(2 * time.Second)
+	setInterfaceNameserverValues(mainInterface, serverAddresses)
 
-	getDNSServerCommand := `(Get-DnsClientServerAddress "vEthernet (Default Switch)").ServerAddresses`
-	stdOut, _, _ := powershell.Execute(getDNSServerCommand)
+	time.Sleep(2 * time.Second)
 
-	if !strings.Contains(stdOut, serviceConfig.IP) {
+	if !contains(getInterfaceNameserverValues(mainInterface), serviceConfig.IP) {
 		err := errors.New("Nameserver not successfully set")
 		result.Success = false
 		result.Error = err.Error()
@@ -32,3 +31,56 @@ func runPostStartForOS(serviceConfig services.ServicePostStartConfig, result *se
 	result.Success = true
 	return *result, nil
 }
+
+func getInterfaceNameserverValues(iface string) []string {
+	getDNSServerCommand := fmt.Sprintf(`(Get-DnsClientServerAddress "%s")[0].ServerAddresses`, iface)
+	stdOut, _, _ := powershell.Execute(getDNSServerCommand)
+
+	return parseLines(stdOut)
+}
+
+func contains(s []string, e string) bool {
+	for _, v := range s {
+		if v == e {
+			return true
+		}
+	}
+	return false
+}
+
+func formatValues(serverAddresses []string) string {
+	var out string
+	for index, serverAddress := range serverAddresses {
+		out = fmt.Sprintf(`%s"%s"`, out, serverAddress)
+		if index < len(serverAddresses)-1 {
+			out = fmt.Sprintf(`%s, `, out)
+		}
+	}
+
+	return out
+}
+
+func setInterfaceNameserverValues(iface string, serverAddresses []string) {
+	setDNSServerCommand := fmt.Sprintf(`Set-DNSClientServerAddress "%s" -ServerAddresses (%s)`,
+		iface, formatValues(serverAddresses))
+
+	powershell.ExecuteAsAdmin(setDNSServerCommand)
+}
+
+func getMainInterface() string {
+	getMainInterfaceCommand := `(Get-NetAdapter | Where-Object {$_.MediaConnectionState -eq 'Connected'} | Sort-Object LinkSpeed -Descending)[0].Name`
+	mainInterface, _, _ := powershell.Execute(getMainInterfaceCommand)
+
+	return strings.TrimSpace(mainInterface)
+}
+
+func parseLines(input string) []string {
+	output := []string{}
+
+	s := bufio.NewScanner(strings.NewReader(input))
+	for s.Scan() {
+		output = append(output, s.Text())
+	}
+
+	return output
+}