Standardize on IChildResource and SetParent

Child resources, such as a ServerVolume or ImageMetadata often
need references back to the parent. It should always be protected
and only exposed through IChildResource. The ApiBuilder is responsible
for setting a parent reference or id.

The type should be reference, and then try casting to a full object
if additional functionality is needed. The child won't always have
a full object available, if it must have one, then the method
should be moved elsewhere.

Author: carolynvs

src/corelib/Compute/v2_1/ComputeApiBuilder.cs

@@ -907,13 +907,14 @@ public virtual async Task<TPage> ListImageDetailsAsync<TPage>(Url url, Cancellat
 
         /// <summary />
         public virtual async Task<T> ListServerVolumesAsync<T>(string serverId, CancellationToken cancellationToken = default(CancellationToken))
-            where T : IEnumerable<IServiceResource>
+            where T : IEnumerable<IServiceResource>, IEnumerable<IChildResource>
         {
-            var result = await BuidListServerVolumesAsync(serverId, cancellationToken)
+            var results = await BuidListServerVolumesAsync(serverId, cancellationToken)
                 .SendAsync()
                 .ReceiveJson<T>();
-            result.PropogateOwner(this);
-            return result;
+            results.PropogateOwner(this);
+            results.SetParent(serverId);
+            return results;
         }
 
         /// <summary />
@@ -930,12 +931,13 @@ public virtual async Task<TPage> ListImageDetailsAsync<TPage>(Url url, Cancellat
 
         /// <summary />
         public virtual async Task<T> AttachVolumeAsync<T>(string serverId, object request, CancellationToken cancellationToken = default(CancellationToken))
-            where T : IServiceResource
+            where T : IServiceResource, IChildResource
         {
             T result = await BuildAttachVolumeAsync(serverId, request, cancellationToken)
                 .SendAsync()
                 .ReceiveJson<T>();
             result.PropogateOwner(this);
+            result.SetParent(serverId);
             return result;
         }
 

src/corelib/Compute/v2_1/Image.cs

@@ -96,7 +96,7 @@ public ImageType Type
         [OnDeserialized]
         private void OnDeserialized(StreamingContext context)
         {
-            Metadata.Image = this;
+            Metadata.SetParent(this);
         }
     }
 }

src/corelib/Compute/v2_1/ImageMetadata.cs

@@ -15,17 +15,27 @@ public class ImageMetadata : Dictionary<string, string>, IHaveExtraData, IChildR
     {
         /// <summary />
         [JsonIgnore]
-        internal protected Image Image { get; set; }
+        protected ImageReference Image { get; set; }
 
         /// <summary />
         [JsonExtensionData]
         IDictionary<string, JToken> IHaveExtraData.Data { get; set; } = new Dictionary<string, JToken>();
 
         object IServiceResource.Owner { get; set; }
 
+        internal void SetParent(ImageReference parent)
+        {
+            Image = parent;
+        }
+
         void IChildResource.SetParent(string parentId)
         {
-            Image = new Image {Id = parentId};
+            SetParent(new Image {Id = parentId});
+        }
+
+        void IChildResource.SetParent(object parent)
+        {
+            SetParent((Image)parent);
         }
 
         /// <summary />

src/corelib/Compute/v2_1/Server.cs

@@ -175,22 +175,24 @@ public string AdminPassword
             result.CopyProperties(this);
         }
 
-        /// <inheritdoc />
-        public override async Task<ServerVolume> AttachVolumeAsync(ServerVolumeDefinition volume, CancellationToken cancellationToken = new CancellationToken())
+        /// <summary />
+        /// <exception cref="InvalidOperationException">When this instance was not constructed by the <see cref="ComputeService"/>, as it is missing the appropriate internal state to execute service calls.</exception>
+        public virtual async Task<ServerVolume> AttachVolumeAsync(ServerVolumeDefinition volume, CancellationToken cancellationToken = default(CancellationToken))
         {
-            var result = await base.AttachVolumeAsync(volume, cancellationToken);
-            result.Server = this;
+            var compute = this.GetOwnerOrThrow<ComputeApiBuilder>();
+            var result = await compute.AttachVolumeAsync<ServerVolume>(Id, volume, cancellationToken).ConfigureAwait(false);
             AttachedVolumes.Add(result);
+            ((IChildResource)result).SetParent(this);
             return result;
         }
-
+        
         /// <summary />
         [OnDeserialized]
         private void OnDeserializedMethod(StreamingContext context)
         {
-            foreach (var volume in AttachedVolumes)
+            foreach (IChildResource volume in AttachedVolumes)
             {
-                volume.Server = this;
+                volume.SetParent(this);
             }
         }
     }

src/corelib/Compute/v2_1/ServerExtensions.cs

@@ -81,8 +81,8 @@ public static void Evacuate(this ServerReference server, EvacuateServerRequest r
             server.EvacuateAsync(request).ForceSynchronous();
         }
 
-        /// <inheritdoc cref="ServerReference.AttachVolumeAsync"/>
-        public static ServerVolume AttachVolume(this ServerReference server, ServerVolumeDefinition volume)
+        /// <inheritdoc cref="Server.AttachVolumeAsync"/>
+        public static ServerVolume AttachVolume(this Server server, ServerVolumeDefinition volume)
         {
             return server.AttachVolumeAsync(volume).ForceSynchronous();
         }

src/corelib/Compute/v2_1/ServerReference.cs

@@ -103,14 +103,6 @@ public class ServerReference : IHaveExtraData, IServiceResource
             await compute.EvacuateServerAsync(Id, request, cancellationToken).ConfigureAwait(false);
         }
 
-        /// <summary />
-        /// <exception cref="InvalidOperationException">When this instance was not constructed by the <see cref="ComputeService"/>, as it is missing the appropriate internal state to execute service calls.</exception>
-        public virtual async Task<ServerVolume> AttachVolumeAsync(ServerVolumeDefinition volume, CancellationToken cancellationToken = default(CancellationToken))
-        {
-            var compute = this.GetOwnerOrThrow<ComputeApiBuilder>();
-            return await compute.AttachVolumeAsync<ServerVolume>(Id, volume, cancellationToken).ConfigureAwait(false);
-        }
-
         /// <summary />
         /// <exception cref="InvalidOperationException">When this instance was not constructed by the <see cref="ComputeService"/>, as it is missing the appropriate internal state to execute service calls.</exception>
         public async Task<IEnumerable<ServerVolume>> ListVolumesAsync(CancellationToken cancellationToken = default(CancellationToken))

src/corelib/Compute/v2_1/ServerVolumeReference.cs

@@ -15,16 +15,26 @@ public class ServerVolumeReference : IHaveExtraData, IChildResource
     {
         /// <summary />
         [JsonIgnore]
-        protected internal Server Server { get; set; }
+        protected ServerReference ServerRef { get; set; }
 
         /// <summary />
         public Identifier Id { get; set; }
 
         object IServiceResource.Owner { get; set; }
 
+        internal void SetParent(ServerReference parent)
+        {
+            ServerRef = parent;
+        }
+
+        void IChildResource.SetParent(object parent)
+        {
+            SetParent((Server)parent);
+        }
+
         void IChildResource.SetParent(string parentId)
         {
-            Server = new Server { Id = parentId };
+            SetParent(new ServerReference {Id = parentId});
         }
 
         /// <summary />
@@ -34,7 +44,7 @@ void IChildResource.SetParent(string parentId)
         /// <summary />
         protected void AssertServerIsSet([CallerMemberName]string callerName = "")
         {
-            if (Server != null)
+            if (ServerRef != null)
                 return;
 
             throw new InvalidOperationException(string.Format($"{callerName} can only be used on instances which were constructed by the ComputeServer. Use ComputeService.{callerName} instead."));
@@ -47,8 +57,8 @@ protected void AssertServerIsSet([CallerMemberName]string callerName = "")
             AssertServerIsSet();
 
             var compute = this.GetOwnerOrThrow<ComputeApiBuilder>();
-            var result = await compute.GetServerVolumeAsync<ServerVolume>(Server.Id, Id, cancellationToken);
-            result.Server = Server;
+            var result = await compute.GetServerVolumeAsync<ServerVolume>(ServerRef.Id, Id, cancellationToken);
+            result.ServerRef = ServerRef;
             return result;
         }
 
@@ -59,11 +69,15 @@ protected void AssertServerIsSet([CallerMemberName]string callerName = "")
             AssertServerIsSet(); 
 
             var compute = this.GetOwnerOrThrow<ComputeApiBuilder>();
-            await compute.DetachVolumeAsync(Server.Id, Id, cancellationToken);
+            await compute.DetachVolumeAsync(ServerRef.Id, Id, cancellationToken);
 
-            var attachedVolume = Server.AttachedVolumes.FirstOrDefault(v => v.Id == Id);
-            if(attachedVolume != null)
-                Server.AttachedVolumes.Remove(attachedVolume);
+            var server = ServerRef as Server;
+            if (server != null)
+            {
+                var attachedVolume = server.AttachedVolumes.FirstOrDefault(v => v.Id == Id);
+                if (attachedVolume != null)
+                    server.AttachedVolumes.Remove(attachedVolume);
+            }
         }
     }
 }

src/corelib/Extensions/TypeExtensions.cs

@@ -94,6 +94,15 @@ public static void PropogateOwner(this IEnumerable<IServiceResource> resources,
                 resource.PropogateOwner(owner);
             }
         }
+
+        /// <summary />
+        public static void SetParent(this IEnumerable<IChildResource> resources, string parentId)
+        {
+            foreach (var resource in resources)
+            {
+                resource.SetParent(parentId);
+            }
+        }
     }
 
 }

src/corelib/Serialization/IServiceResource.cs

@@ -20,6 +20,11 @@ public interface IServiceResource
     /// </summary>
     public interface IChildResource : IServiceResource
     {
+        /// <summary>
+        /// Called after deserialization to bootstrap a link from the child back to the parent resource.
+        /// </summary>
+        void SetParent(object parent);
+
         /// <summary>
         /// Called after deserialization to bootstrap a link from the child back to the parent resource.
         /// </summary>

src/testing/integration/Compute/v2_1/ServerTests.cs

@@ -310,7 +310,7 @@ public async Task ServerVolumesTest()
             Trace.WriteLine($"Created server named: {server.Name}");
 
             Trace.WriteLine("Creating a test volume...");
-            var volume = _testData.BlockStorage.CreateVolume();
+            var volume = await _testData.CreateVolume();
             Identifier volumeId = volume.Id;
             _testData.BlockStorage.StorageProvider.WaitForVolumeAvailable(volumeId);
 
@@ -327,12 +327,12 @@ public async Task ServerVolumesTest()
             Assert.NotNull(attachedVolume);
 
             Trace.WriteLine("Retrieving attached volume details...");
-            attachedVolume = await volumeRef.GetServerVolumeAsync();
-            Assert.Equal(volumeId, attachedVolume.VolumeId);
-            Assert.Equal(server.Id, attachedVolume.ServerId);
+            var serverVolume = await volumeRef.GetServerVolumeAsync();
+            Assert.Equal(volumeId, serverVolume.VolumeId);
+            Assert.Equal(server.Id, serverVolume.ServerId);
 
             Trace.WriteLine("Detaching the volume...");
-            await attachedVolume.DetachAsync();
+            await volumeRef.DetachAsync();
             Assert.False(server.AttachedVolumes.Any(v => v.Id == volumeId));
             _testData.BlockStorage.StorageProvider.WaitForVolumeAvailable(volumeId);
         }