From 03122df7719a4d1c7a0dc2cfe2e427a29d07c8cb Mon Sep 17 00:00:00 2001
From: Ole Markus With <o.with@sportradar.com>
Date: Sat, 8 Aug 2020 18:28:13 +0200
Subject: [PATCH] Make it possible to change subnet dns servers

---
 upup/pkg/fi/cloudup/openstacktasks/port.go    |  4 +--
 .../fi/cloudup/openstacktasks/port_test.go    |  2 +-
 upup/pkg/fi/cloudup/openstacktasks/subnet.go  | 31 ++++++++++++++-----
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/upup/pkg/fi/cloudup/openstacktasks/port.go b/upup/pkg/fi/cloudup/openstacktasks/port.go
index 0b0751d3579ae..cda20675cf4c9 100644
--- a/upup/pkg/fi/cloudup/openstacktasks/port.go
+++ b/upup/pkg/fi/cloudup/openstacktasks/port.go
@@ -61,7 +61,7 @@ func (s *Port) CompareWithID() *string {
 	return s.ID
 }
 
-func NewPortTaskFromCloud(cloud openstack.OpenstackCloud, lifecycle *fi.Lifecycle, port *ports.Port, find *Port) (*Port, error) {
+func newPortTaskFromCloud(cloud openstack.OpenstackCloud, lifecycle *fi.Lifecycle, port *ports.Port, find *Port) (*Port, error) {
 	additionalSecurityGroupIDs := map[string]struct{}{}
 	if find != nil {
 		for _, sg := range find.AdditionalSecurityGroups {
@@ -131,7 +131,7 @@ func (s *Port) Find(context *fi.Context) (*Port, error) {
 	} else if len(rs) != 1 {
 		return nil, fmt.Errorf("found multiple ports with name: %s", fi.StringValue(s.Name))
 	}
-	return NewPortTaskFromCloud(cloud, s.Lifecycle, &rs[0], s)
+	return newPortTaskFromCloud(cloud, s.Lifecycle, &rs[0], s)
 }
 
 func (s *Port) Run(context *fi.Context) error {
diff --git a/upup/pkg/fi/cloudup/openstacktasks/port_test.go b/upup/pkg/fi/cloudup/openstacktasks/port_test.go
index 1908736fe001b..74ef04c8d61b5 100644
--- a/upup/pkg/fi/cloudup/openstacktasks/port_test.go
+++ b/upup/pkg/fi/cloudup/openstacktasks/port_test.go
@@ -207,7 +207,7 @@ func Test_NewPortTaskFromCloud(t *testing.T) {
 
 	for _, testCase := range tests {
 		t.Run(testCase.desc, func(t *testing.T) {
-			actual, err := NewPortTaskFromCloud(testCase.cloud, &testCase.lifecycle, testCase.cloudPort, testCase.foundPort)
+			actual, err := newPortTaskFromCloud(testCase.cloud, &testCase.lifecycle, testCase.cloudPort, testCase.foundPort)
 
 			if !reflect.DeepEqual(err, testCase.expectedError) {
 				t.Errorf("Error differs:\n%v\n\tinstead of\n%v", err, testCase.expectedError)
diff --git a/upup/pkg/fi/cloudup/openstacktasks/subnet.go b/upup/pkg/fi/cloudup/openstacktasks/subnet.go
index d140235db0cff..6b3ca1fcfa820 100644
--- a/upup/pkg/fi/cloudup/openstacktasks/subnet.go
+++ b/upup/pkg/fi/cloudup/openstacktasks/subnet.go
@@ -115,7 +115,7 @@ func (s *Subnet) Run(context *fi.Context) error {
 	return fi.DefaultDeltaRunMethod(s, context)
 }
 
-func (_ *Subnet) CheckChanges(a, e, changes *Subnet) error {
+func (*Subnet) CheckChanges(a, e, changes *Subnet) error {
 	if a == nil {
 		if e.Name == nil {
 			return fi.RequiredField("Name")
@@ -130,9 +130,6 @@ func (_ *Subnet) CheckChanges(a, e, changes *Subnet) error {
 		if changes.Name != nil {
 			return fi.CannotChangeField("Name")
 		}
-		if changes.DNSServers != nil {
-			return fi.CannotChangeField("DNSServers")
-		}
 		if changes.Network != nil {
 			return fi.CannotChangeField("Network")
 		}
@@ -143,7 +140,7 @@ func (_ *Subnet) CheckChanges(a, e, changes *Subnet) error {
 	return nil
 }
 
-func (_ *Subnet) RenderOpenstack(t *openstack.OpenstackAPITarget, a, e, changes *Subnet) error {
+func (*Subnet) RenderOpenstack(t *openstack.OpenstackAPITarget, a, e, changes *Subnet) error {
 	if a == nil {
 		klog.V(2).Infof("Creating Subnet with name:%q", fi.StringValue(e.Name))
 
@@ -176,9 +173,27 @@ func (_ *Subnet) RenderOpenstack(t *openstack.OpenstackAPITarget, a, e, changes
 		klog.V(2).Infof("Creating a new Openstack subnet, id=%s", v.ID)
 		return nil
 	} else {
-		err := t.Cloud.AppendTag(openstack.ResourceTypeSubnet, fi.StringValue(a.ID), fi.StringValue(changes.Tag))
-		if err != nil {
-			return fmt.Errorf("Error appending tag to subnet: %v", err)
+		if changes.Tag != nil {
+			err := t.Cloud.AppendTag(openstack.ResourceTypeSubnet, fi.StringValue(a.ID), fi.StringValue(changes.Tag))
+			if err != nil {
+				return fmt.Errorf("error appending tag to subnet: %v", err)
+			}
+		}
+		client := t.Cloud.(openstack.OpenstackCloud).NetworkingClient()
+
+		opt := subnets.UpdateOpts{}
+
+		if changes.DNSServers != nil {
+			dnsNameSrv := make([]string, len(e.DNSServers))
+			for i, ns := range e.DNSServers {
+				dnsNameSrv[i] = fi.StringValue(ns)
+			}
+			opt.DNSNameservers = &dnsNameSrv
+		}
+		result := subnets.Update(client, fi.StringValue(a.ID), opt)
+		klog.Infof("Updated %v", opt)
+		if result.Err != nil {
+			return fmt.Errorf("error updating subnet %v: %v", a.ID, result.Err)
 		}
 	}
 	e.ID = a.ID