Add System.Diagnostics.TextMapPropagator support

src/Hosting/Hosting/src/GenericHost/GenericWebHostBuilder.cs

@@ -87,6 +87,7 @@ public GenericWebHostBuilder(IHostBuilder builder, WebHostBuilderOptions options
                 services.TryAddSingleton(sp => new DiagnosticListener("Microsoft.AspNetCore"));
                 services.TryAddSingleton<DiagnosticSource>(sp => sp.GetRequiredService<DiagnosticListener>());
                 services.TryAddSingleton(sp => new ActivitySource("Microsoft.AspNetCore"));
+                services.TryAddSingleton(DistributedContextPropagator.Current);
 
                 services.TryAddSingleton<IHttpContextFactory, DefaultHttpContextFactory>();
                 services.TryAddScoped<IMiddlewareFactory, MiddlewareFactory>();

src/Hosting/Hosting/src/GenericHost/GenericWebHostedService.cs

@@ -21,24 +21,25 @@ namespace Microsoft.AspNetCore.Hosting
 {
     internal sealed partial class GenericWebHostService : IHostedService
     {
-        public GenericWebHostService(
-            IOptions<GenericWebHostServiceOptions> options,
-            IServer server,
-            ILoggerFactory loggerFactory,
-            DiagnosticListener diagnosticListener,
-            ActivitySource activitySource,
-            IHttpContextFactory httpContextFactory,
-            IApplicationBuilderFactory applicationBuilderFactory,
-            IEnumerable<IStartupFilter> startupFilters,
-            IConfiguration configuration,
-            IWebHostEnvironment hostingEnvironment)
+        public GenericWebHostService(IOptions<GenericWebHostServiceOptions> options,
+                                     IServer server,
+                                     ILoggerFactory loggerFactory,
+                                     DiagnosticListener diagnosticListener,
+                                     ActivitySource activitySource,
+                                     DistributedContextPropagator propagator,
+                                     IHttpContextFactory httpContextFactory,
+                                     IApplicationBuilderFactory applicationBuilderFactory,
+                                     IEnumerable<IStartupFilter> startupFilters,
+                                     IConfiguration configuration,
+                                     IWebHostEnvironment hostingEnvironment)
         {
             Options = options.Value;
             Server = server;
             Logger = loggerFactory.CreateLogger("Microsoft.AspNetCore.Hosting.Diagnostics");
             LifetimeLogger = loggerFactory.CreateLogger("Microsoft.Hosting.Lifetime");
             DiagnosticListener = diagnosticListener;
             ActivitySource = activitySource;
+            Propagator = propagator;
             HttpContextFactory = httpContextFactory;
             ApplicationBuilderFactory = applicationBuilderFactory;
             StartupFilters = startupFilters;
@@ -53,6 +54,7 @@ public GenericWebHostService(
         public ILogger LifetimeLogger { get; }
         public DiagnosticListener DiagnosticListener { get; }
         public ActivitySource ActivitySource { get; }
+        public DistributedContextPropagator Propagator { get; }
         public IHttpContextFactory HttpContextFactory { get; }
         public IApplicationBuilderFactory ApplicationBuilderFactory { get; }
         public IEnumerable<IStartupFilter> StartupFilters { get; }
@@ -116,7 +118,7 @@ public async Task StartAsync(CancellationToken cancellationToken)
                 application = ErrorPageBuilder.BuildErrorPageApplication(HostingEnvironment.ContentRootFileProvider, Logger, showDetailedErrors, ex);
             }
 
-            var httpApplication = new HostingApplication(application, Logger, DiagnosticListener, ActivitySource, HttpContextFactory);
+            var httpApplication = new HostingApplication(application, Logger, DiagnosticListener, ActivitySource, Propagator, HttpContextFactory);
 
             await Server.StartAsync(httpApplication, cancellationToken);
 

src/Hosting/Hosting/src/Internal/HostingApplication.cs

@@ -24,10 +24,11 @@ public HostingApplication(
             ILogger logger,
             DiagnosticListener diagnosticSource,
             ActivitySource activitySource,
+            DistributedContextPropagator propagator,
             IHttpContextFactory httpContextFactory)
         {
             _application = application;
-            _diagnostics = new HostingApplicationDiagnostics(logger, diagnosticSource, activitySource);
+            _diagnostics = new HostingApplicationDiagnostics(logger, diagnosticSource, activitySource, propagator);
             if (httpContextFactory is DefaultHttpContextFactory factory)
             {
                 _defaultHttpContextFactory = factory;

src/Hosting/Hosting/src/Internal/HostingApplicationDiagnostics.cs

@@ -7,12 +7,9 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Runtime.CompilerServices;
-using System.Web;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.Extensions.Logging;
-using Microsoft.Extensions.Primitives;
-using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNetCore.Hosting
 {
@@ -31,13 +28,19 @@ internal class HostingApplicationDiagnostics
 
         private readonly ActivitySource _activitySource;
         private readonly DiagnosticListener _diagnosticListener;
+        private readonly DistributedContextPropagator _propagator;
         private readonly ILogger _logger;
 
-        public HostingApplicationDiagnostics(ILogger logger, DiagnosticListener diagnosticListener, ActivitySource activitySource)
+        public HostingApplicationDiagnostics(
+            ILogger logger,
+            DiagnosticListener diagnosticListener,
+            ActivitySource activitySource,
+            DistributedContextPropagator propagator)
         {
             _logger = logger;
             _diagnosticListener = diagnosticListener;
             _activitySource = activitySource;
+            _propagator = propagator;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -279,38 +282,37 @@ private static void RecordRequestStartEventLog(HttpContext httpContext)
             {
                 return null;
             }
-
             var headers = httpContext.Request.Headers;
-            var requestId = headers.TraceParent;
-            if (requestId.Count == 0)
-            {
-                requestId = headers.RequestId;
-            }
-
-            if (!StringValues.IsNullOrEmpty(requestId))
+            _propagator.ExtractTraceIdAndState(headers,
+                static (object? carrier, string fieldName, out string? fieldValue, out IEnumerable<string>? fieldValues) =>
+                {
+                    fieldValues = default;
+                    var headers = (IHeaderDictionary)carrier!;
+                    fieldValue = headers[fieldName];
+                },
+                out var requestId,
+                out var traceState);
+
+            if (!string.IsNullOrEmpty(requestId))
             {
                 activity.SetParentId(requestId);
-                var traceState = headers.TraceState;
-                if (traceState.Count > 0)
+                if (!string.IsNullOrEmpty(traceState))
                 {
                     activity.TraceStateString = traceState;
                 }
-
-                // We expect baggage to be empty by default
-                // Only very advanced users will be using it in near future, we encourage them to keep baggage small (few items)
-                var baggage = headers.GetCommaSeparatedValues(HeaderNames.Baggage);
-                if (baggage.Length == 0)
+                var baggage = _propagator.ExtractBaggage(headers, static (object? carrier, string fieldName, out string? fieldValue, out IEnumerable<string>? fieldValues) =>
                 {
-                    baggage = headers.GetCommaSeparatedValues(HeaderNames.CorrelationContext);
-                }
+                    fieldValues = default;
+                    var headers = (IHeaderDictionary)carrier!;
+                    fieldValue = headers[fieldName];
+                });
 
-                // AddBaggage adds items at the beginning  of the list, so we need to add them in reverse to keep the same order as the client
-                // An order could be important if baggage has two items with the same key (that is allowed by the contract)
-                for (var i = baggage.Length - 1; i >= 0; i--)
+                // Order could be important if baggage has two items with the same key (that is allowed by the contract)
+                if (baggage is not null)
                 {
-                    if (NameValueHeaderValue.TryParse(baggage[i], out var baggageItem))
+                    foreach (var baggageItem in baggage)
                     {
-                        activity.AddBaggage(baggageItem.Name.ToString(), HttpUtility.UrlDecode(baggageItem.Value.ToString()));
+                        activity.AddBaggage(baggageItem.Key, baggageItem.Value);
                     }
                 }
             }

src/Hosting/Hosting/src/Internal/WebHost.cs

@@ -157,8 +157,9 @@ public async Task StartAsync(CancellationToken cancellationToken = default)
 
             var diagnosticSource = _applicationServices.GetRequiredService<DiagnosticListener>();
             var activitySource = _applicationServices.GetRequiredService<ActivitySource>();
+            var propagator = _applicationServices.GetRequiredService<DistributedContextPropagator>();
             var httpContextFactory = _applicationServices.GetRequiredService<IHttpContextFactory>();
-            var hostingApp = new HostingApplication(application, _logger, diagnosticSource, activitySource, httpContextFactory);
+            var hostingApp = new HostingApplication(application, _logger, diagnosticSource, activitySource, propagator, httpContextFactory);
             await Server.StartAsync(hostingApp, cancellationToken).ConfigureAwait(false);
             _startedServer = true;
 

src/Hosting/Hosting/src/WebHostBuilder.cs

@@ -293,6 +293,7 @@ private IServiceCollection BuildCommonServices(out AggregateException? hostingSt
             services.TryAddSingleton(sp => new DiagnosticListener("Microsoft.AspNetCore"));
             services.TryAddSingleton<DiagnosticSource>(sp => sp.GetRequiredService<DiagnosticListener>());
             services.TryAddSingleton(sp => new ActivitySource("Microsoft.AspNetCore"));
+            services.TryAddSingleton(DistributedContextPropagator.Current);
 
             services.AddTransient<IApplicationBuilderFactory, ApplicationBuilderFactory>();
             services.AddTransient<IHttpContextFactory, DefaultHttpContextFactory>();

src/Hosting/Hosting/test/HostingApplicationDiagnosticsTests.cs

@@ -397,7 +397,7 @@ public void ActivityBaggagePreservesItemsOrder()
                 KeyValuePair.Create("Key1","value3")
             };
 
-            Assert.Equal(expectedBaggage, Activity.Current.Baggage);
+            Assert.Equal(expectedBaggage, Activity.Current.Baggage.ToArray());
         }
 
         [Fact]
@@ -552,6 +552,7 @@ private static HostingApplication CreateApplication(out FeatureCollection featur
                 logger ?? new NullScopeLogger(),
                 diagnosticListener ?? new NoopDiagnosticListener(),
                 activitySource ?? new ActivitySource("Microsoft.AspNetCore"),
+                DistributedContextPropagator.CreateDefaultPropagator(),
                 httpContextFactory.Object);
 
             return hostingApplication;

src/Hosting/Hosting/test/HostingApplicationTests.cs

@@ -196,6 +196,7 @@ private static HostingApplication CreateApplication(IHttpContextFactory httpCont
                 NullLogger.Instance,
                 new DiagnosticListener("Microsoft.AspNetCore"),
                 activitySource ?? new ActivitySource("Microsoft.AspNetCore"),
+                DistributedContextPropagator.CreateDefaultPropagator(),
                 httpContextFactory);
 
             return hostingApplication;