Add Polly resilience policies

clients/dotnet/MxGateway.Client/MxGatewayClient.cs

@@ -1,6 +1,8 @@
 using Grpc.Core;
 using Grpc.Net.Client;
+using Microsoft.Extensions.Logging;
 using MxGateway.Contracts.Proto;
+using Polly;
 
 namespace MxGateway.Client;
 
@@ -11,6 +13,7 @@ public sealed class MxGatewayClient : IAsyncDisposable
 {
     private readonly GrpcChannel _channel;
     private readonly IMxGatewayClientTransport _transport;
+    private readonly ResiliencePipeline _safeUnaryRetryPipeline;
     private bool _disposed;
 
     internal MxGatewayClient(
@@ -22,6 +25,9 @@ public sealed class MxGatewayClient : IAsyncDisposable
 
         Options = options;
         _transport = transport ?? throw new ArgumentNullException(nameof(transport));
+        _safeUnaryRetryPipeline = MxGatewayClientRetryPolicy.Create(
+            options.Retry,
+            options.LoggerFactory?.CreateLogger<MxGatewayClient>());
         _channel = null!;
     }
 
@@ -32,6 +38,9 @@ public sealed class MxGatewayClient : IAsyncDisposable
         _channel = channel;
         _transport = transport;
         Options = transport.Options;
+        _safeUnaryRetryPipeline = MxGatewayClientRetryPolicy.Create(
+            Options.Retry,
+            Options.LoggerFactory?.CreateLogger<MxGatewayClient>());
     }
 
     public MxGatewayClientOptions Options { get; }
@@ -88,7 +97,9 @@ public sealed class MxGatewayClient : IAsyncDisposable
         ArgumentNullException.ThrowIfNull(request);
         ThrowIfDisposed();
 
-        return _transport.CloseSessionAsync(request, CreateCallOptions(cancellationToken));
+        return ExecuteSafeUnaryAsync(
+            token => _transport.CloseSessionAsync(request, CreateCallOptions(token)),
+            cancellationToken);
     }
 
     public Task<MxCommandReply> InvokeAsync(
@@ -98,6 +109,13 @@ public sealed class MxGatewayClient : IAsyncDisposable
         ArgumentNullException.ThrowIfNull(request);
         ThrowIfDisposed();
 
+        if (MxGatewayClientRetryPolicy.IsRetryableCommand(request.Command?.Kind ?? MxCommandKind.Unspecified))
+        {
+            return ExecuteSafeUnaryAsync(
+                token => _transport.InvokeAsync(request, CreateCallOptions(token)),
+                cancellationToken);
+        }
+
         return _transport.InvokeAsync(request, CreateCallOptions(cancellationToken));
     }
 
@@ -136,6 +154,16 @@ public sealed class MxGatewayClient : IAsyncDisposable
             cancellationToken);
     }
 
+    private Task<T> ExecuteSafeUnaryAsync<T>(
+        Func<CancellationToken, Task<T>> call,
+        CancellationToken cancellationToken)
+    {
+        return _safeUnaryRetryPipeline.ExecuteAsync(
+                async token => await call(token).ConfigureAwait(false),
+                cancellationToken)
+            .AsTask();
+    }
+
     private void ThrowIfDisposed()
     {
         ObjectDisposedException.ThrowIf(_disposed, this);