Use System.Reactive.Async and IAsyncObservable instead of custom ISubscriber abstraction

prototypes/multi-module-prototype/examples/multi-module-example/ComposeUI.Example.DataService/MonthlySalesDataService.cs

@@ -12,6 +12,8 @@
 //  * and limitations under the License.
 //  */
 
+using System.Reactive;
+using System.Reactive.Linq;
 using Microsoft.Extensions.Logging;
 using MorganStanley.ComposeUI.Messaging;
 
@@ -38,7 +40,7 @@ public async Task Start()
                 _subscriptions.Add(
                     await _messageRouter.SubscribeAsync(
                         "proto_select_marketData",
-                        Subscriber.Create<TopicMessage>(OnSymbolSelected, OnSymbolSelectionError)));
+                        AsyncObserver.Create<TopicMessage>(OnSymbolSelected, OnSymbolSelectionError, () => default)));
             }
             catch (Exception exception)
             {

src/messaging/dotnet/src/Client/Client/MessageRouterClient.cs

@@ -56,10 +56,10 @@ public ValueTask ConnectAsync(CancellationToken cancellationToken = default)
 
     public ValueTask<IDisposable> SubscribeAsync(
         string topicName,
-        ISubscriber<TopicMessage> subscriber,
+        IAsyncObserver<TopicMessage> subscriber,
         CancellationToken cancellationToken = default)
     {
-        Topic.Validate(topicName);
+        Protocol.Topic.Validate(topicName);
         CheckState();
 
         var needsSubscription = false;
@@ -69,11 +69,11 @@ public ValueTask<IDisposable> SubscribeAsync(
             _ =>
             {
                 needsSubscription = true;
-                return new Topic<TopicMessage>(topicName, _logger);
+                return new Topic(topicName, _logger);
             });
 
         return needsSubscription
-            ? SubscribeAsyncCore(topicName, topic, subscriber, cancellationToken)
+            ? SubscribeAsyncCore(topic, subscriber, cancellationToken)
             : ValueTask.FromResult(topic.Subscribe(subscriber));
     }
 
@@ -83,7 +83,7 @@ public ValueTask PublishAsync(
         PublishOptions options = default,
         CancellationToken cancellationToken = default)
     {
-        Topic.Validate(topic);
+        Protocol.Topic.Validate(topic);
 
         return SendMessageAsync(
             new PublishMessage
@@ -192,7 +192,7 @@ public ValueTask DisposeAsync()
 
     private readonly ConcurrentDictionary<string, TaskCompletionSource<AbstractResponse>> _pendingRequests = new();
     private readonly ConcurrentDictionary<string, MessageHandler> _endpointHandlers = new();
-    private readonly ConcurrentDictionary<string, Topic<TopicMessage>> _topics = new();
+    private readonly ConcurrentDictionary<string, Topic> _topics = new();
     private readonly MessageRouterOptions _options;
     private readonly ILogger<MessageRouterClient> _logger;
 
@@ -537,9 +537,8 @@ private async ValueTask RegisterServiceCore(
     }
 
     private async ValueTask<IDisposable> SubscribeAsyncCore(
-        string topicName,
-        Topic<TopicMessage> topic,
-        ISubscriber<TopicMessage> subscriber,
+        Topic topic,
+        IAsyncObserver<TopicMessage> subscriber,
         CancellationToken cancellationToken)
     {
         var subscription = topic.Subscribe(subscriber);
@@ -549,7 +548,7 @@ private async ValueTask<IDisposable> SubscribeAsyncCore(
             await SendMessageAsync(
                 new SubscribeMessage
                 {
-                    Topic = topicName,
+                    Topic = topic.Name
                 },
                 cancellationToken);
 
@@ -726,7 +725,7 @@ private class StateChangeEvents
         public Task? SendReceiveCompleted;
     }
 
-    private class Topic<T>
+    private class Topic
     {
         public string Name { get; }
 
@@ -736,7 +735,7 @@ public Topic(string name, ILogger logger)
             _logger = logger;
         }
 
-        public IDisposable Subscribe(ISubscriber<T> subscriber)
+        public IDisposable Subscribe(IAsyncObserver<TopicMessage> subscriber)
         {
             lock (_mutex)
             {
@@ -762,7 +761,7 @@ private void Unsubscribe(Subscription subscription)
             // TODO: Unsubscribe from the topic completely if no more subscribers
         }
 
-        public void OnNext(T value)
+        public void OnNext(TopicMessage value)
         {
             lock (_mutex)
             {
@@ -817,7 +816,7 @@ public void Complete()
 
         private class Subscription : IDisposable
         {
-            public Subscription(Topic<T> topic, ISubscriber<T> subscriber, ILogger logger)
+            public Subscription(Topic topic, IAsyncObserver<TopicMessage> subscriber, ILogger logger)
             {
                 _subscriber = subscriber;
                 _topic = topic;
@@ -830,7 +829,7 @@ public void Dispose()
                 _topic.Unsubscribe(this);
             }
 
-            public void OnNext(T value)
+            public void OnNext(TopicMessage value)
             {
                 _queue.Writer.TryWrite(
                     value); // Since the queue is unbounded, this will succeed unless the channel was completed
@@ -862,7 +861,7 @@ private async Task ProcessMessages()
                             {
                                 _logger.LogError(
                                     e,
-                                    $"Exception thrown while invoking {nameof(ISubscriber<T>.OnNextAsync)} on a subscriber of topic '{{TopicName}}': {{ExceptionMessage}}",
+                                    $"Exception thrown while invoking {nameof(IAsyncObserver<TopicMessage>.OnNextAsync)} on a subscriber of topic '{{TopicName}}': {{ExceptionMessage}}",
                                     _topic.Name,
                                     e.Message);
                             }
@@ -877,7 +876,7 @@ private async Task ProcessMessages()
                     {
                         _logger.LogError(
                             e,
-                            $"Exception thrown while invoking {nameof(ISubscriber<T>.OnCompletedAsync)} on a subscriber of topic '{{TopicName}}': {{ExceptionMessage}}",
+                            $"Exception thrown while invoking {nameof(IAsyncObserver<TopicMessage>.OnCompletedAsync)} on a subscriber of topic '{{TopicName}}': {{ExceptionMessage}}",
                             _topic.Name,
                             e.Message);
                     }
@@ -892,24 +891,24 @@ private async Task ProcessMessages()
                     {
                         _logger.LogError(
                             e2,
-                            $"Exception thrown while invoking {nameof(ISubscriber<T>.OnErrorAsync)} on a subscriber of topic '{{TopicName}}': {{ExceptionMessage}}",
+                            $"Exception thrown while invoking {nameof(IAsyncObserver<TopicMessage>.OnErrorAsync)} on a subscriber of topic '{{TopicName}}': {{ExceptionMessage}}",
                             _topic.Name,
                             e2.Message);
                     }
                 }
             }
 
-            private readonly ISubscriber<T> _subscriber;
+            private readonly IAsyncObserver<TopicMessage> _subscriber;
 
-            private readonly Channel<T> _queue = Channel.CreateUnbounded<T>(
+            private readonly Channel<TopicMessage> _queue = Channel.CreateUnbounded<TopicMessage>(
                 new UnboundedChannelOptions
                 {
                     AllowSynchronousContinuations = false,
                     SingleReader = true,
                     SingleWriter = false
                 });
 
-            private readonly Topic<T> _topic;
+            private readonly Topic _topic;
             private readonly ILogger _logger;
         }
     }

src/messaging/dotnet/src/Client/MorganStanley.ComposeUI.Messaging.Client.csproj

@@ -18,7 +18,8 @@
 	  <PackageReference Include="Microsoft.Extensions.Options" Version="6.0.0" />
 	  <PackageReference Include="Nito.AsyncEx" Version="5.1.2" />
 	  <PackageReference Include="System.IO.Pipelines" Version="6.0.3" />
-	  <PackageReference Include="System.Reactive" Version="5.0.0" />
+	  <PackageReference Include="System.Reactive" Version="6.0.0" />
+	  <PackageReference Include="System.Reactive.Async" Version="6.0.0-alpha.3" />
 	</ItemGroup>
 
 	<ItemGroup>

src/messaging/dotnet/src/Core/IMessageRouter.cs

@@ -45,7 +45,7 @@ public interface IMessageRouter : IAsyncDisposable
     /// <returns></returns>
     ValueTask<IDisposable> SubscribeAsync(
         string topic,
-        ISubscriber<TopicMessage> subscriber,
+        IAsyncObserver<TopicMessage> subscriber,
         CancellationToken cancellationToken = default);
 
     /// <summary>

src/messaging/dotnet/src/Core/MessageRouterExtensions.cs

@@ -10,6 +10,8 @@
 // or implied. See the License for the specific language governing permissions
 // and limitations under the License.
 
+using System.Reactive;
+using System.Reactive.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading.Channels;
 
@@ -87,7 +89,7 @@ public static ValueTask<IDisposable> SubscribeAsync(
         IObserver<TopicMessage> observer,
         CancellationToken cancellationToken = default)
     {
-        var innerSubscriber = Subscriber.Create<TopicMessage>(
+        var innerSubscriber = AsyncObserver.Create<TopicMessage>(
             message =>
             {
                 observer.OnNext(message);
@@ -126,7 +128,7 @@ public static ValueTask<IDisposable> SubscribeAsync(
         IObserver<string?> observer,
         CancellationToken cancellationToken = default)
     {
-        var innerSubscriber = Subscriber.Create<TopicMessage>(
+        var innerSubscriber = AsyncObserver.Create<TopicMessage>(
             message =>
             {
                 observer.OnNext(message.Payload?.GetString());
@@ -162,10 +164,10 @@ public static ValueTask<IDisposable> SubscribeAsync(
     public static ValueTask<IDisposable> SubscribeAsync(
         this IMessageRouter messageRouter,
         string topic,
-        ISubscriber<string?> subscriber,
+        IAsyncObserver<string?> subscriber,
         CancellationToken cancellationToken = default)
     {
-        var innerSubscriber = Subscriber.Create<TopicMessage>(
+        var innerSubscriber = AsyncObserver.Create<TopicMessage>(
             message => subscriber.OnNextAsync(message.Payload?.GetString()),
             subscriber.OnErrorAsync,
             subscriber.OnCompletedAsync);
@@ -189,15 +191,15 @@ public static async IAsyncEnumerable<TopicMessage> SubscribeAsync(
 
         using var subscription = await messageRouter.SubscribeAsync(
             topic,
-            Subscriber.Create<TopicMessage>(
-                onNext: message => channel.Writer.WriteAsync(message, cancellationToken),
-                onError: exception =>
+            AsyncObserver.Create<TopicMessage>(
+                onNextAsync: message => channel.Writer.WriteAsync(message, cancellationToken),
+                onErrorAsync: exception =>
                 {
                     channel.Writer.TryComplete(exception);
 
                     return default;
                 },
-                onCompleted: () =>
+                onCompletedAsync: () =>
                 {
                     channel.Writer.TryComplete();
 

src/messaging/dotnet/src/Core/MorganStanley.ComposeUI.Messaging.Core.csproj

@@ -15,7 +15,8 @@
 
 	<ItemGroup>
 		<PackageReference Include="Microsoft.IO.RecyclableMemoryStream" Version="2.2.1" />
-		<PackageReference Include="System.Reactive" Version="5.0.0" />
+		<PackageReference Include="System.Reactive" Version="6.0.0" />
+		<PackageReference Include="System.Reactive.Async" Version="6.0.0-alpha.3" />
 		<PackageReference Include="System.Text.Json" Version="6.0.7" />
 	</ItemGroup>
 

src/messaging/dotnet/src/Server/MorganStanley.ComposeUI.Messaging.Server.csproj

@@ -8,7 +8,7 @@
 	</PropertyGroup>
 
 	<ItemGroup>
-		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.1" />
+		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.0" />
 		<PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="6.0.0" />
 		<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="6.0.3" />
 		<PackageReference Include="Microsoft.Extensions.Options" Version="6.0.0" />