feat: added retry logic to HttpRemoteQueryRunner

Author: SebastianKuesters

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints.UnitTests/HttpRemoteQueryRunners/HttpRemoteQueryRunnerTests.cs

@@ -0,0 +1,89 @@
+using System.Net;
+using System.Text.Json;
+using FluentAssertions;
+using Moq;
+using RestSharp;
+using Wemogy.CQRS.Common.ValueObjects;
+using Wemogy.CQRS.Extensions.FastEndpoints.Common;
+using Wemogy.CQRS.Extensions.FastEndpoints.RemoteQueryRunners;
+using Wemogy.CQRS.Extensions.FastEndpoints.UnitTests.TestApplication.Queries.RequestTestContext;
+using Wemogy.CQRS.Extensions.FastEndpoints.UnitTests.TestApplication.ValueObjects;
+
+namespace Wemogy.CQRS.Extensions.FastEndpoints.UnitTests.HttpRemoteQueryRunners;
+
+public class HttpRemoteQueryRunnerTests
+{
+    [Fact]
+    public async Task QueryAsync_ShouldRetryRequestAndReturnResult()
+    {
+        // Arrange
+        var query = new RequestTestContextQuery();
+        var testContext = new TestContext()
+        {
+            UserId = Guid.NewGuid().ToString()
+        };
+        var resultContent = JsonSerializer.Serialize(testContext, JsonOptions.JsonSerializerOptions);
+        var responses = new Queue<RestResponse>();
+        responses.Enqueue(new RestResponse()
+        {
+            StatusCode = HttpStatusCode.ServiceUnavailable
+        });
+        responses.Enqueue(new RestResponse()
+        {
+            StatusCode = HttpStatusCode.OK,
+            Content = resultContent,
+
+            // Set IsSuccessful to true
+            IsSuccessStatusCode = true,
+            ResponseStatus = ResponseStatus.Completed
+        });
+
+        var restClientMock = new Mock<IRestClient>();
+        restClientMock
+            .Setup(
+                m => m.ExecuteAsync(
+                    It.IsAny<RestRequest>(),
+                    It.IsAny<CancellationToken>()))
+            .ReturnsAsync(responses.Dequeue);
+
+        var httpRemoteQueryRunner = new HttpRemoteQueryRunner<RequestTestContextQuery, TestContext>(restClientMock.Object, string.Empty);
+        var request = new QueryRequest<RequestTestContextQuery>(query, new List<CommandQueryDependency>());
+
+        // Act
+        var result = await httpRemoteQueryRunner.QueryAsync(request, CancellationToken.None);
+
+        // Assert
+        result.Should().BeEquivalentTo(testContext);
+        responses.Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task QueryAsync_ShouldThrowWithoutResultAfterMaxRetryReachedRequest()
+    {
+        // Arrange
+        var query = new RequestTestContextQuery();
+        var testContext = new TestContext()
+        {
+            UserId = Guid.NewGuid().ToString()
+        };
+        var restClientMock = new Mock<IRestClient>();
+        restClientMock
+            .Setup(
+                m => m.ExecuteAsync(
+                    It.IsAny<RestRequest>(),
+                    It.IsAny<CancellationToken>()))
+            .ReturnsAsync(() => new RestResponse()
+            {
+                StatusCode = HttpStatusCode.ServiceUnavailable
+            });
+
+        var httpRemoteQueryRunner = new HttpRemoteQueryRunner<RequestTestContextQuery, TestContext>(restClientMock.Object, string.Empty);
+        var request = new QueryRequest<RequestTestContextQuery>(query, new List<CommandQueryDependency>());
+
+        // Act
+        var exception = await Record.ExceptionAsync(() => httpRemoteQueryRunner.QueryAsync(request, CancellationToken.None));
+
+        // Assert
+        exception.Should().NotBeNull();
+    }
+}

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/RemoteQueryRunners/HttpRemoteQueryRunner.cs

@@ -1,4 +1,6 @@
 using System.Text.Json;
+using Polly;
+using Polly.Contrib.WaitAndRetry;
 using RestSharp;
 using Wemogy.Core.Errors;
 using Wemogy.Core.Extensions;
@@ -14,25 +16,35 @@ namespace Wemogy.CQRS.Extensions.FastEndpoints.RemoteQueryRunners;
 public class HttpRemoteQueryRunner<TQuery, TResult> : IRemoteQueryRunner<TQuery, TResult>
     where TQuery : IQuery<TResult>
 {
-    private readonly RestClient _restClient;
+    private readonly IRestClient _restClient;
 
     /// <summary>
     /// This is the sub-path of the client base path
     /// </summary>
     private readonly string _urlPath;
+    private readonly IAsyncPolicy<RestResponse> _retryPolicy;
 
-    public HttpRemoteQueryRunner(RestClient restClient, string urlPath)
+    public HttpRemoteQueryRunner(IRestClient restClient, string urlPath)
     {
         _restClient = restClient;
         _urlPath = urlPath;
+        var retryCount = 3;
+        var delay = Backoff.ExponentialBackoff(
+            TimeSpan.FromMilliseconds(100),
+            retryCount);
+        _retryPolicy = Policy
+            .HandleResult<RestResponse>(x => !x.IsSuccessful)
+            .WaitAndRetryAsync(delay);
     }
 
     public async Task<TResult> QueryAsync(QueryRequest<TQuery> query, CancellationToken cancellationToken)
     {
         var request = new RestRequest(_urlPath)
             .AddJsonBody(query);
 
-        var response = await _restClient.PostAsync(request, cancellationToken: cancellationToken);
+        var response = await _retryPolicy.ExecuteAsync(
+            ct => _restClient.PostAsync(request, cancellationToken: ct),
+            cancellationToken);
 
         if (!response.IsSuccessful)
         {