SIANXSVC-1206: dotnet-e5e writes logging messages after output in non…

…-keepalive mode (#19)

src/Anexia.E5E.Tests/Integration/NonKeepAliveModeTests.cs

@@ -0,0 +1,39 @@
+using System.Threading.Tasks;
+
+using Anexia.E5E.Functions;
+using Anexia.E5E.Tests.Helpers;
+using Anexia.E5E.Tests.TestHelpers;
+
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Anexia.E5E.Tests.Integration;
+
+public class NonKeepAliveModeTests : IntegrationTestBase
+{
+	public NonKeepAliveModeTests(ITestOutputHelper outputHelper) : base(outputHelper)
+	{
+		Host.ConfigureEndpoints(cfg =>
+		{
+			cfg.RegisterEntrypoint(TestE5ERuntimeOptions.DefaultEntrypointName,
+				_ => Task.FromResult(E5EResponse.From("response")));
+		}, new[] { TestE5ERuntimeOptions.DefaultEntrypointName, "+++", "0", "---" });
+	}
+
+	public override Task InitializeAsync() => Host.StartAsync();
+
+
+	[Fact]
+	public async Task ShouldEndWithJsonResponse()
+	{
+		var (stdout, _) = await Host.WriteOnceAsync(builder => builder.WithData("request"));
+		Assert.EndsWith(@"{""result"":{""data"":""response"",""type"":""text""}}", stdout);
+	}
+
+	[Fact]
+	public async Task ShouldNotWriteExecutionEndToStderr()
+	{
+		var (_, stderr) = await Host.WriteOnceAsync(builder => builder.WithData("request"));
+		Assert.Empty(stderr);
+	}
+}

src/Anexia.E5E.Tests/TestHelpers/IntegrationTestBase.cs

@@ -15,7 +15,7 @@ protected IntegrationTestBase(ITestOutputHelper outputHelper) : base(outputHelpe
 
 	protected TestHostBuilder Host { get; }
 
-	public Task InitializeAsync()
+	public virtual Task InitializeAsync()
 	{
 		return Task.CompletedTask;
 	}

src/Anexia.E5E/Extensions/HostBuilderExtensions.cs

@@ -71,10 +71,12 @@ public static IHostBuilder UseAnexiaE5E(this IHostBuilder hb, string[]? args,
 	private sealed class E5EHostBuilderWrapper : IHostBuilder
 	{
 		private readonly IHostBuilder _inner;
+		private readonly E5ERuntimeOptions _options;
 
 		public E5EHostBuilderWrapper(IHostBuilder inner, E5ERuntimeOptions runtimeOptions)
 		{
 			_inner = inner;
+			_options = runtimeOptions;
 			_inner.ConfigureServices((_, services) =>
 			{
 				services.AddHostedService<E5ECommunicationService>();
@@ -110,6 +112,17 @@ public IHostBuilder ConfigureServices(Action<HostBuilderContext, IServiceCollect
 
 		public IHost Build()
 		{
+			if (_options.KeepAlive)
+				return new E5EHostWrapper(_inner.Build());
+
+			// If we are in the non-keepalive mode (should happen rarely), we *must* not write anything to stdout
+			// after a successful response. Because the default logging mechanism do not allow to set the logging
+			// level after startup, we enforce that all logs are written to stderr.
+			//
+			// This does **not** affect our ConsoleAbstraction. Why? The ConsoleLogger just references System.Console.Out,
+			// and our abstraction calls System.Console.OpenStandardOutput and is therefore using the actual /dev/stdout.
+			Console.SetOut(Console.Error);
+
 			return new E5EHostWrapper(_inner.Build());
 		}
 

src/Anexia.E5E/Hosting/E5ECommunicationService.cs

@@ -90,13 +90,15 @@ private async Task ListenForIncomingMessagesAsync(CancellationToken stoppingToke
 			var response = await RespondToLineAsync(line, stoppingToken).ConfigureAwait(false);
 			await _console.WriteToStdoutAsync(response).ConfigureAwait(false);
 
-			// After every *successful* execution, we need to write the execution sequence. This applies to ping
-			// messages as well. We do not write it after errors, otherwise our logs would get sent into the void.
-			await _console.WriteToStdoutAsync(_options.DaemonExecutionTerminationSequence).ConfigureAwait(false);
-			await _console.WriteToStderrAsync(_options.DaemonExecutionTerminationSequence).ConfigureAwait(false);
-
 			// If we should keep it alive (which is notably the default), do that.
-			if (_options.KeepAlive) continue;
+			if (_options.KeepAlive)
+			{
+				// After every *successful* execution, we need to write the execution sequence. This applies to ping
+				// messages as well. We do not write it after errors, otherwise our logs would get sent into the void.
+				await _console.WriteToStdoutAsync(_options.DaemonExecutionTerminationSequence).ConfigureAwait(false);
+				await _console.WriteToStderrAsync(_options.DaemonExecutionTerminationSequence).ConfigureAwait(false);
+				continue;
+			}
 
 			// Otherwise, we just stop the processing at this point.
 			break;