Features/exceptions pipeline integration (#308)

docs/web/docker.md

@@ -98,7 +98,7 @@ sqlserver           # Test database
 database.migrations # Fresh schema
 database.seed      # Test data
 api.specs          # Reqnroll BDD tests
-unit.tests         # All Features.*.Tests unit test projects
+unit.tests         # All Features.*.Tests and Shared.*.Tests unit test projects
 frontend.tests     # Storybook Vitest + Playwright suites (own Playwright image)
 ```
 

docs/web/testing.md

@@ -76,10 +76,11 @@ docker compose --env-file web/.env.test -f web/docker-compose.test.yaml down -v
 
 You can run individual test projects locally without Docker:
 
-### Feature slice unit tests
+### Feature slice and shared unit tests
 
 Each feature slice has its own test project, covering its command/query
-handlers:
+handlers. Shared cross-cutting code (e.g. MediatR pipeline behaviors) has
+its own test project under `Shared/`:
 
 ```bash
 cd web/backend
@@ -87,9 +88,10 @@ dotnet test Features/Features.Users.Tests/Features.Users.Tests.csproj
 dotnet test Features/Features.Breweries.Tests/Features.Breweries.Tests.csproj
 dotnet test Features/Features.Emails.Tests/Features.Emails.Tests.csproj
 dotnet test Features/Features.PhotoUpload.Tests/Features.PhotoUpload.Tests.csproj
+dotnet test Shared/Shared.Application.Tests/Shared.Application.Tests.csproj
 
 # Or run all of them at once via the solution:
-for proj in Features/*.Tests; do dotnet test "$proj"; done
+for proj in Features/*.Tests Shared/*.Tests; do dotnet test "$proj"; done
 ```
 
 **Requirements**:

web/backend/API/API.Core/Dockerfile

@@ -35,6 +35,7 @@ COPY ["Features/Features.Users/Features.Users.csproj", "Features/Features.Users/
 COPY ["Features/Features.Users.Tests/Features.Users.Tests.csproj", "Features/Features.Users.Tests/"]
 COPY ["Configuration/Configuration.csproj", "Configuration/"]
 COPY ["Shared/Shared.Application/Shared.Application.csproj", "Shared/Shared.Application/"]
+COPY ["Shared/Shared.Application.Tests/Shared.Application.Tests.csproj", "Shared/Shared.Application.Tests/"]
 COPY ["Shared/Shared.Contracts/Shared.Contracts.csproj", "Shared/Shared.Contracts/"]
 RUN dotnet restore "Biergarten.API.slnx"
 COPY . .

web/backend/API/API.Core/ServiceCollectionExtensions.cs

@@ -46,6 +46,7 @@ internal static class ServiceCollectionExtensions
                     cfg.RegisterServicesFromAssembly(typeof(UploadPhotoCommand).Assembly);
                     cfg.RegisterServicesFromAssembly(typeof(IEmailDispatcher).Assembly);
                     cfg.RegisterServicesFromAssembly(typeof(CityController).Assembly);
+                    cfg.AddOpenBehavior(typeof(UnhandledExceptionLoggingBehavior<,>));
                     cfg.AddOpenBehavior(typeof(ValidationBehavior<,>));
                 });
 

web/backend/API/API.Specs/Dockerfile

@@ -25,6 +25,7 @@ COPY ["Features/Features.Users/Features.Users.csproj", "Features/Features.Users/
 COPY ["Features/Features.Users.Tests/Features.Users.Tests.csproj", "Features/Features.Users.Tests/"]
 COPY ["Configuration/Configuration.csproj", "Configuration/"]
 COPY ["Shared/Shared.Application/Shared.Application.csproj", "Shared/Shared.Application/"]
+COPY ["Shared/Shared.Application.Tests/Shared.Application.Tests.csproj", "Shared/Shared.Application.Tests/"]
 COPY ["Shared/Shared.Contracts/Shared.Contracts.csproj", "Shared/Shared.Contracts/"]
 RUN dotnet restore "Biergarten.API.slnx"
 COPY . .

web/backend/Biergarten.API.slnx

@@ -47,5 +47,6 @@
     <Folder Name="/Shared/">
         <Project Path="Shared/Shared.Contracts/Shared.Contracts.csproj" />
         <Project Path="Shared/Shared.Application/Shared.Application.csproj" />
+        <Project Path="Shared/Shared.Application.Tests/Shared.Application.Tests.csproj" />
     </Folder>
 </Solution>

web/backend/Dockerfile.tests

@@ -5,11 +5,11 @@ COPY . .
 RUN dotnet restore "Biergarten.API.slnx"
 RUN dotnet build "Biergarten.API.slnx" -c $BUILD_CONFIGURATION
 
-# Runs every Features.*.Tests project (unit + DbMocker-backed repository tests). API.Specs is
+# Runs every Features.*.Tests and Shared.*.Tests project (unit + DbMocker-backed repository
-# excluded here since it's a separate BDD/integration suite, run by its own compose service
+# tests). API.Specs is excluded here since it's a separate BDD/integration suite, run by its own
-# against the live, seeded database.
+# compose service against the live, seeded database.
 FROM build AS final
 ARG BUILD_CONFIGURATION=Release
 WORKDIR /src
 RUN mkdir -p /app/test-results
-ENTRYPOINT ["sh", "-c", "set -e; for proj in Features/*.Tests; do dotnet test \"$proj\" -c ${BUILD_CONFIGURATION:-Release} --logger \"trx;LogFileName=/app/test-results/$(basename \"$proj\").trx\"; done"]
+ENTRYPOINT ["sh", "-c", "set -e; for proj in Features/*.Tests Shared/*.Tests; do dotnet test \"$proj\" -c ${BUILD_CONFIGURATION:-Release} --logger \"trx;LogFileName=/app/test-results/$(basename \"$proj\").trx\"; done"]

web/backend/Shared/Shared.Application.Tests/Behaviors/UnhandledExceptionLoggingBehaviorTests.cs

@@ -0,0 +1,111 @@
+using FluentAssertions;
+using FluentValidation;
+using FluentValidation.Results;
+using MediatR;
+using Microsoft.Extensions.Logging;
+using Moq;
+using Shared.Application.Behaviors;
+
+namespace Shared.Application.Tests.Behaviors;
+
+public class UnhandledExceptionLoggingBehaviorTests
+{
+    private readonly Mock<
+        ILogger<UnhandledExceptionLoggingBehavior<TestRequest, TestResponse>>
+    > _loggerMock = new();
+
+    private UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> CreateBehavior() =>
+        new(_loggerMock.Object);
+
+    [Fact]
+    public async Task Handle_WhenHandlerThrowsGenericException_LogsOnceAndRethrows()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        InvalidOperationException thrown = new("boom");
+        RequestHandlerDelegate<TestResponse> next = () => throw thrown;
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+
+        (await act.Should().ThrowAsync<InvalidOperationException>())
+            .Which.Should()
+            .BeSameAs(thrown);
+        VerifyLogError(Times.Once());
+    }
+
+    [Fact]
+    public async Task Handle_WhenValidationExceptionThrown_DoesNotLogAndRethrows()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        ValidationException thrown = new([new ValidationFailure("Username", "is required")]);
+        RequestHandlerDelegate<TestResponse> next = () => throw thrown;
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+
+        (await act.Should().ThrowAsync<ValidationException>()).Which.Should().BeSameAs(thrown);
+        VerifyLogError(Times.Never());
+    }
+
+    [Fact]
+    public async Task Handle_WhenHandlerSucceeds_DoesNotLogAndReturnsResponse()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        TestResponse response = new("ok");
+        RequestHandlerDelegate<TestResponse> next = () => Task.FromResult(response);
+
+        TestResponse result = await behavior.Handle(request, next, CancellationToken.None);
+
+        result.Should().BeSameAs(response);
+        VerifyLogError(Times.Never());
+    }
+
+    [Fact]
+    public async Task Handle_WhenHandlerThrows_RedactsSensitiveFieldsInLoggedPayload()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        RequestHandlerDelegate<TestResponse> next = () =>
+            throw new InvalidOperationException("boom");
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+        await act.Should().ThrowAsync<InvalidOperationException>();
+
+        string loggedMessage = CaptureLoggedMessage();
+        loggedMessage.Should().Contain("aaron").And.NotContain("hunter2");
+    }
+
+    private void VerifyLogError(Times times) =>
+        _loggerMock.Verify(
+            l =>
+                l.Log(
+                    LogLevel.Error,
+                    It.IsAny<EventId>(),
+                    It.IsAny<It.IsAnyType>(),
+                    It.IsAny<Exception>(),
+                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
+                ),
+            times
+        );
+
+    private string CaptureLoggedMessage()
+    {
+        var invocation = _loggerMock
+            .Invocations.Where(i => i.Method.Name == nameof(ILogger.Log))
+            .Should()
+            .ContainSingle()
+            .Subject;
+
+        object state = invocation.Arguments[2];
+        object? exception = invocation.Arguments[3];
+        object formatter = invocation.Arguments[4];
+        System.Reflection.MethodInfo invokeMethod = formatter.GetType().GetMethod("Invoke")!;
+
+        return (string)invokeMethod.Invoke(formatter, [state, exception])!;
+    }
+}
+
+public record TestRequest(string Username, string Password) : IRequest<TestResponse>;
+
+public record TestResponse(string Value);

web/backend/Shared/Shared.Application.Tests/Shared.Application.Tests.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <IsPackable>false</IsPackable>
+        <RootNamespace>Shared.Application.Tests</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1"/>
+        <PackageReference Include="xunit" Version="2.9.2"/>
+        <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2"/>
+        <PackageReference Include="Moq" Version="4.20.72"/>
+        <PackageReference Include="FluentAssertions" Version="7.2.0"/>
+        <PackageReference Include="FluentValidation" Version="11.3.0"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <Using Include="Xunit"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\Shared.Application\Shared.Application.csproj"/>
+    </ItemGroup>
+</Project>

web/backend/Shared/Shared.Application/Behaviors/UnhandledExceptionLoggingBehavior.cs

@@ -0,0 +1,86 @@
+using System.Text.Json;
+using System.Text.Json.Serialization.Metadata;
+using FluentValidation;
+using MediatR;
+using Microsoft.Extensions.Logging;
+
+namespace Shared.Application.Behaviors;
+
+/// <summary>
+///     MediatR pipeline behavior that logs unhandled exceptions together with the request type and
+///     payload, then rethrows them unchanged for <c>GlobalExceptionFilter</c> to map to a status code.
+/// </summary>
+public class UnhandledExceptionLoggingBehavior<TRequest, TResponse>(
+    ILogger<UnhandledExceptionLoggingBehavior<TRequest, TResponse>> logger
+) : IPipelineBehavior<TRequest, TResponse>
+    where TRequest : IRequest<TResponse>
+{
+    private static readonly string[] SensitiveFieldNames = ["password", "token"];
+
+    private static readonly JsonSerializerOptions SerializerOptions = new()
+    {
+        TypeInfoResolver = new DefaultJsonTypeInfoResolver
+        {
+            Modifiers = { RedactSensitiveProperties },
+        },
+    };
+
+    /// <inheritdoc/>
+    public async Task<TResponse> Handle(
+        TRequest request,
+        RequestHandlerDelegate<TResponse> next,
+        CancellationToken cancellationToken
+    )
+    {
+        try
+        {
+            return await next();
+        }
+        catch (ValidationException)
+        {
+            // Expected: ValidationBehavior already reports these as request errors, not incidents.
+            throw;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(
+                ex,
+                "Unhandled exception while processing {RequestName}: {RequestPayload}",
+                typeof(TRequest).Name,
+                Serialize(request)
+            );
+            throw;
+        }
+    }
+
+    private static string Serialize(TRequest request)
+    {
+        try
+        {
+            return JsonSerializer.Serialize(request, SerializerOptions);
+        }
+        catch (Exception)
+        {
+            return "<unable to serialize request payload>";
+        }
+    }
+
+    private static void RedactSensitiveProperties(JsonTypeInfo typeInfo)
+    {
+        if (typeInfo.Kind != JsonTypeInfoKind.Object)
+            return;
+
+        foreach (JsonPropertyInfo property in typeInfo.Properties)
+        {
+            if (property.PropertyType != typeof(string))
+                continue;
+
+            if (
+                SensitiveFieldNames.Any(name =>
+                    property.Name.Contains(name, StringComparison.OrdinalIgnoreCase)
+                )
+            )
+                property.Get = static _ => "***REDACTED***";
+        }
+    }
+}

web/backend/Shared/Shared.Application/Shared.Application.csproj

@@ -9,5 +9,6 @@
     <ItemGroup>
         <PackageReference Include="MediatR" Version="12.4.1" />
         <PackageReference Include="FluentValidation" Version="11.3.0" />
+        <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.1" />
     </ItemGroup>
 </Project>