From a9133706877b7aa41a661c5ba5d0b113c177aadd Mon Sep 17 00:00:00 2001
From: Jesse Keating <jkeating@j2solutions.net>
Date: Fri, 24 Jul 2015 15:41:19 -0700
Subject: [PATCH] Handle non-updatable openstack subnet details

Some things cannot be updated via the API, so check for those and fail
if the user is wanting to update them. Also don't try to update ipv6
stuff, as that doesn't work and will cause a traceback.
---
 .../modules/cloud/openstack/os_subnet.py      | 44 +++++++++++++++----
 1 file changed, 36 insertions(+), 8 deletions(-)

diff --git a/lib/ansible/modules/cloud/openstack/os_subnet.py b/lib/ansible/modules/cloud/openstack/os_subnet.py
index b62eb10b0cc..22876c80869 100644
--- a/lib/ansible/modules/cloud/openstack/os_subnet.py
+++ b/lib/ansible/modules/cloud/openstack/os_subnet.py
@@ -144,9 +144,38 @@ EXAMPLES = '''
     ipv6_address_mode: dhcpv6-stateless
 '''
 
+def _can_update(subnet, module, cloud):
+    """Check for differences in non-updatable values"""
+    network_name = module.params['network_name']
+    cidr = module.params['cidr']
+    ip_version = int(module.params['ip_version'])
+    ipv6_ra_mode = module.params['ipv6_ra_mode']
+    ipv6_a_mode = module.params['ipv6_address_mode']
 
-def _needs_update(subnet, module):
+    if network_name:
+        network = cloud.get_network(network_name)
+        if network:
+            netid = network['id']
+        else:
+            module.fail_json(msg='No network found for %s' % network_name)
+        if netid != subnet['network_id']:
+                module.fail_json(msg='Cannot update network_name in existing \
+                                      subnet')
+    if ip_version and subnet['ip_version'] != ip_version:
+        module.fail_json(msg='Cannot update ip_version in existing subnet')
+    if ipv6_ra_mode and subnet.get('ipv6_ra_mode', None) != ip_version:
+        module.fail_json(msg='Cannot update ipv6_ra_mode in existing subnet')
+    if ipv6_a_mode and subnet.get('ipv6_address_mode', None) != ipv6_a_mode:
+        module.fail_json(msg='Cannot update ipv6_address_mode in existing \
+                              subnet')
+
+def _needs_update(subnet, module, cloud):
     """Check for differences in the updatable values."""
+
+    # First check if we are trying to update something we're not allowed to
+    _can_update(subnet, module, cloud)
+
+    # now check for the things we are allowed to update
     enable_dhcp = module.params['enable_dhcp']
     subnet_name = module.params['name']
     pool_start = module.params['allocation_pool_start']
@@ -176,12 +205,12 @@ def _needs_update(subnet, module):
     return False
 
 
-def _system_state_change(module, subnet):
+def _system_state_change(module, subnet, cloud):
     state = module.params['state']
     if state == 'present':
         if not subnet:
             return True
-        return _needs_update(subnet, module)
+        return _needs_update(subnet, module, cloud)
     if state == 'absent' and subnet:
         return True
     return False
@@ -245,7 +274,8 @@ def main():
         subnet = cloud.get_subnet(subnet_name)
 
         if module.check_mode:
-            module.exit_json(changed=_system_state_change(module, subnet))
+            module.exit_json(changed=_system_state_change(module, subnet,
+                                                          cloud))
 
         if state == 'present':
             if not subnet:
@@ -261,16 +291,14 @@ def main():
                                              ipv6_address_mode=ipv6_a_mode)
                 changed = True
             else:
-                if _needs_update(subnet, module):
+                if _needs_update(subnet, module, cloud):
                     cloud.update_subnet(subnet['id'],
                                         subnet_name=subnet_name,
                                         enable_dhcp=enable_dhcp,
                                         gateway_ip=gateway_ip,
                                         dns_nameservers=dns,
                                         allocation_pools=pool,
-                                        host_routes=host_routes,
-                                        ipv6_ra_mode=ipv6_ra_mode,
-                                        ipv6_address_mode=ipv6_a_mode)
+                                        host_routes=host_routes)
                     changed = True
                 else:
                     changed = False