NetworkSecurityGroup as an optional parameter in NetworkInterface.

Author: sergey-shandar

src/ResourceManager/Common/Commands.Common.Strategies/Network/NetworkInterfaceStrategy.cs

@@ -35,7 +35,7 @@ public static ResourceConfig<NetworkInterface> CreateNetworkInterfaceConfig(
             string name,
             NestedResourceConfig<Subnet, VirtualNetwork> subnet,
             ResourceConfig<PublicIPAddress> publicIPAddress,
-            ResourceConfig<NetworkSecurityGroup> networkSecurityGroup)
+            ResourceConfig<NetworkSecurityGroup> networkSecurityGroup = null)
             => Strategy.CreateConfig(
                 resourceGroup,
                 name,
@@ -53,10 +53,12 @@ public static ResourceConfig<NetworkInterface> CreateNetworkInterfaceConfig(
                             }
                         }
                     },
-                    NetworkSecurityGroup = new NetworkSecurityGroup
-                    {
-                        Id = networkSecurityGroup.GetId(subscription).IdToString()
-                    }
+                    NetworkSecurityGroup = networkSecurityGroup == null 
+                        ? null 
+                        : new NetworkSecurityGroup
+                        {
+                            Id = networkSecurityGroup.GetId(subscription).IdToString()
+                        }
                 },
                 new IEntityConfig[] { subnet, publicIPAddress, networkSecurityGroup });
     }

src/ResourceManager/Common/Commands.Common.Strategies/ResourceConfigExtensions.cs

@@ -50,7 +50,7 @@ public static ResourceConfig<TModel> CreateConfig<TModel>(
                 resourceGroup.Name,
                 name,
                 createModel,
-                dependencies.EmptyIfNull().Concat(new[] { resourceGroup }));
+                dependencies.EmptyIfNull().Where(d => d != null).Concat(new[] { resourceGroup }));
 
         public static async Task<TModel> GetAsync<TModel>(
             this ResourceConfig<TModel> config,