Pass tracecontext to pdf generator

src/Altinn.App.Api/Extensions/ServiceCollectionExtensions.cs

@@ -356,6 +356,15 @@ public async Task StartAsync(CancellationToken cancellationToken)
         public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
     }
 
+    /// <summary>
+    /// PDF generation works by using a headless browser to render the frontend of an app instance.
+    /// To make  debugging PDF generation failures easier, we want requests originating from the PDF generator to be
+    /// contained in the root trace (process/next) as children. The frontend will set this header when making requests to the app backend in PDF mode.
+    /// </summary>
+    /// <param name="headers">Request headers attached to the span</param>
+    /// <returns></returns>
+    private static bool IsPdfGeneratorRequest(IHeaderDictionary headers) => headers.ContainsKey("X-Altinn-IsPdf");
+
     internal sealed class OtelPropagator : TextMapPropagator
     {
         private readonly TextMapPropagator _inner;
@@ -370,8 +379,9 @@ public override PropagationContext Extract<T>(
             Func<T, string, IEnumerable<string>?> getter
         )
         {
-            if (carrier is HttpRequest)
+            if (carrier is HttpRequest req && !IsPdfGeneratorRequest(req.Headers))
                 return default;
+
             return _inner.Extract(context, carrier, getter);
         }
 
@@ -392,7 +402,7 @@ internal sealed class AspNetCorePropagator : DistributedContextPropagator
             PropagatorGetterCallback? getter
         )
         {
-            if (carrier is IHeaderDictionary)
+            if (carrier is IHeaderDictionary headers && !IsPdfGeneratorRequest(headers))
                 return null;
 
             return _inner.ExtractBaggage(carrier, getter);
@@ -405,7 +415,7 @@ public override void ExtractTraceIdAndState(
             out string? traceState
         )
         {
-            if (carrier is IHeaderDictionary)
+            if (carrier is IHeaderDictionary headers && !IsPdfGeneratorRequest(headers))
             {
                 traceId = null;
                 traceState = null;

src/Altinn.App.Core/Features/Telemetry/Telemetry.PdfGeneratorClient.cs

@@ -0,0 +1,12 @@
+using System.Diagnostics;
+
+namespace Altinn.App.Core.Features;
+
+partial class Telemetry
+{
+    internal Activity? StartGeneratePdfClientActivity()
+    {
+        var activity = ActivitySource.StartActivity("PdfGeneratorClient.GeneratePdf");
+        return activity;
+    }
+}

src/Altinn.App.Core/Features/Telemetry/TelemetryActivityExtensions.cs

@@ -344,7 +344,7 @@ internal static Activity SetProblemDetails(this Activity activity, ProblemDetail
     internal static void Errored(this Activity activity, Exception? exception = null, string? error = null)
     {
         activity.SetStatus(ActivityStatusCode.Error, error);
-        if(exception is not null)
+        if (exception is not null)
         {
             activity.AddException(exception);
         }

src/Altinn.App.Core/Infrastructure/Clients/Pdf/PdfGeneratorClient.cs

@@ -1,11 +1,15 @@
+using System.Diagnostics;
 using System.Text;
 using System.Text.Json;
 using Altinn.App.Core.Configuration;
+using Altinn.App.Core.Features;
 using Altinn.App.Core.Internal.Auth;
 using Altinn.App.Core.Internal.Pdf;
 using Altinn.App.Core.Models.Pdf;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using OpenTelemetry.Context.Propagation;
 
 namespace Altinn.App.Core.Infrastructure.Clients.Pdf;
 
@@ -15,40 +19,50 @@ namespace Altinn.App.Core.Infrastructure.Clients.Pdf;
 /// </summary>
 public class PdfGeneratorClient : IPdfGeneratorClient
 {
+    private static readonly TextMapPropagator _w3cPropagator = new TraceContextPropagator();
+
     private static readonly JsonSerializerOptions _jsonSerializerOptions = new()
     {
         PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
     };
 
+    private readonly ILogger<PdfGeneratorClient> _logger;
     private readonly HttpClient _httpClient;
     private readonly PdfGeneratorSettings _pdfGeneratorSettings;
     private readonly PlatformSettings _platformSettings;
     private readonly IUserTokenProvider _userTokenProvider;
     private readonly IHttpContextAccessor _httpContextAccessor;
+    private readonly Telemetry? _telemetry;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="PdfGeneratorClient"/> class.
     /// </summary>
+    /// <param name="logger">The logger.</param>
     /// <param name="httpClient">The HttpClient to use in communication with the PDF generator service.</param>
     /// <param name="pdfGeneratorSettings">
     /// All generic settings needed for communication with the PDF generator service.
     /// </param>
     /// <param name="platformSettings">Links to platform services</param>
     /// <param name="userTokenProvider">A service able to identify the JWT for currently authenticated user.</param>
     /// <param name="httpContextAccessor">http context</param>
+    /// <param name="telemetry">Telemetry service</param>
     public PdfGeneratorClient(
+        ILogger<PdfGeneratorClient> logger,
         HttpClient httpClient,
         IOptions<PdfGeneratorSettings> pdfGeneratorSettings,
         IOptions<PlatformSettings> platformSettings,
         IUserTokenProvider userTokenProvider,
-        IHttpContextAccessor httpContextAccessor
+        IHttpContextAccessor httpContextAccessor,
+        Telemetry? telemetry = null
     )
     {
+        _logger = logger;
         _httpClient = httpClient;
         _userTokenProvider = userTokenProvider;
         _pdfGeneratorSettings = pdfGeneratorSettings.Value;
         _platformSettings = platformSettings.Value;
         _httpContextAccessor = httpContextAccessor;
+        _telemetry = telemetry;
     }
 
     /// <inheritdoc/>
@@ -60,6 +74,8 @@ public async Task<Stream> GeneratePdf(Uri uri, CancellationToken ct)
     /// <inheritdoc/>
     public async Task<Stream> GeneratePdf(Uri uri, string? footerContent, CancellationToken ct)
     {
+        using var activity = _telemetry?.StartGeneratePdfClientActivity();
+
         bool hasWaitForSelector = !string.IsNullOrWhiteSpace(_pdfGeneratorSettings.WaitForSelector);
         PdfGeneratorRequest generatorRequest = new()
         {
@@ -73,6 +89,33 @@ public async Task<Stream> GeneratePdf(Uri uri, string? footerContent, Cancellati
             },
         };
 
+        if (Activity.Current is { } propagateActivity)
+        {
+            // We want the frontend to attach the current trace context to requests
+            // when making downstream requests back to the app backend.
+            // This makes it easier to debug issues (such as slow backend requests during PDF generation).
+            // The frontend expects to see the "traceparent" and "tracestate" values as cookies (as they are easily propagated).
+            // It will then pass them back to the backend in the "traceparent" and "tracestate" headers as per W3C spec.
+            _w3cPropagator.Inject(
+                new PropagationContext(propagateActivity.Context, default),
+                generatorRequest.Cookies,
+                (c, k, v) =>
+                {
+                    if (k != "traceparent" && k != "tracestate")
+                        _logger.LogWarning("Unexpected key '{Key}' when propagating trace context (expected W3C)", k);
+
+                    c.Add(
+                        new PdfGeneratorCookieOptions
+                        {
+                            Name = $"altinn-telemetry-{k}",
+                            Value = v,
+                            Domain = uri.Host,
+                        }
+                    );
+                }
+            );
+        }
+
         generatorRequest.Cookies.Add(
             new PdfGeneratorCookieOptions { Value = _userTokenProvider.GetUserToken(), Domain = uri.Host }
         );

test/Altinn.App.Api.Tests/Controllers/PdfControllerTests.cs

@@ -83,7 +83,10 @@ public async Task Request_In_Dev_Should_Generate()
         var handler = new Mock<HttpMessageHandler>();
         var httpClient = new HttpClient(handler.Object);
 
+        var logger = new Mock<ILogger<PdfGeneratorClient>>();
+
         var pdfGeneratorClient = new PdfGeneratorClient(
+            logger.Object,
             httpClient,
             _pdfGeneratorSettingsOptions,
             _platformSettingsOptions,
@@ -163,7 +166,10 @@ public async Task Request_In_Dev_Should_Include_Frontend_Version()
         var handler = new Mock<HttpMessageHandler>();
         var httpClient = new HttpClient(handler.Object);
 
+        var logger = new Mock<ILogger<PdfGeneratorClient>>();
+
         var pdfGeneratorClient = new PdfGeneratorClient(
+            logger.Object,
             httpClient,
             _pdfGeneratorSettingsOptions,
             _platformSettingsOptions,
@@ -245,7 +251,10 @@ public async Task Request_In_TT02_Should_Ignore_Frontend_Version()
         var handler = new Mock<HttpMessageHandler>();
         var httpClient = new HttpClient(handler.Object);
 
+        var logger = new Mock<ILogger<PdfGeneratorClient>>();
+
         var pdfGeneratorClient = new PdfGeneratorClient(
+            logger.Object,
             httpClient,
             _pdfGeneratorSettingsOptions,
             _platformSettingsOptions,

test/Altinn.App.Api.Tests/CustomWebApplicationFactory.cs

@@ -189,6 +189,7 @@ CancellationToken cancellationToken
                     request.Headers,
                     (c, k, v) => c.TryAddWithoutValidation(k, v)
                 );
+                Assert.Contains(request.Headers, h => h.Key == "traceparent"); // traceparent is mandatory in W3C
             }
             return base.SendAsync(request, cancellationToken);
         }

test/Altinn.App.Api.Tests/Middleware/TelemetryEnrichingMiddlewareTests.Should_Always_Be_A_Root_Trace_Unless_Pdf.verified.txt

@@ -0,0 +1,51 @@
+{
+  Activities: [
+    {
+      ActivityName: GET {org}/{app}/api/v1/applicationmetadata,
+      Tags: [
+        {
+          http.request.method: GET
+        },
+        {
+          http.response.status_code: 200
+        },
+        {
+          http.route: {org}/{app}/api/v1/applicationmetadata
+        },
+        {
+          network.protocol.version: 1.1
+        },
+        {
+          server.address: localhost
+        },
+        {
+          TestId: Guid_1
+        },
+        {
+          url.path: /tdd/contributer-restriction/api/v1/applicationmetadata
+        },
+        {
+          url.scheme: http
+        },
+        {
+          user.authentication.level: 4
+        },
+        {
+          user.authentication.method: Mock
+        },
+        {
+          user.id: 10
+        },
+        {
+          user.name: User10
+        },
+        {
+          user.party.id: Scrubbed
+        }
+      ],
+      IdFormat: W3C,
+      Kind: Server
+    }
+  ],
+  Metrics: []
+}

test/Altinn.App.Api.Tests/Middleware/TelemetryEnrichingMiddlewareTests.cs

@@ -17,7 +17,8 @@ public TelemetryEnrichingMiddlewareTests(WebApplicationFactory<Program> factory,
 
     private (TelemetrySink Telemetry, Func<Task> Request) AnalyzeTelemetry(
         string token,
-        bool includeTraceContext = false
+        bool includeTraceContext = false,
+        bool includePdfHeader = false
     )
     {
         this.OverrideServicesForThisTest = (services) =>
@@ -35,6 +36,8 @@ public TelemetryEnrichingMiddlewareTests(WebApplicationFactory<Program> factory,
         var telemetry = this.Services.GetRequiredService<TelemetrySink>();
 
         client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
+        if (includePdfHeader)
+            client.DefaultRequestHeaders.Add("X-Altinn-IsPdf", "true");
 
         return (telemetry, async () => await client.GetStringAsync($"/{org}/{app}/api/v1/applicationmetadata"));
     }
@@ -110,4 +113,32 @@ public async Task Should_Always_Be_A_Root_Trace()
 
         await telemetry.Snapshot(activity, c => c.ScrubMember(Telemetry.Labels.UserPartyId));
     }
+
+    [Fact]
+    public async Task Should_Always_Be_A_Root_Trace_Unless_Pdf()
+    {
+        var partyId = Random.Shared.Next();
+        var principal = PrincipalUtil.GetUserPrincipal(10, partyId, 4);
+        var token = JwtTokenMock.GenerateToken(principal, new TimeSpan(1, 1, 1));
+
+        var (telemetry, request) = AnalyzeTelemetry(token, includeTraceContext: true, includePdfHeader: true);
+        ActivitySpanId parentSpanId;
+        using (var parentActivity = telemetry.Object.ActivitySource.StartActivity("TestParentActivity"))
+        {
+            Assert.NotNull(parentActivity);
+            parentSpanId = parentActivity.SpanId;
+            await request();
+        }
+        await telemetry.WaitForServerActivity();
+
+        var activities = telemetry.CapturedActivities;
+        var activity = Assert.Single(activities, a => a.Kind == ActivityKind.Server);
+        Assert.True(activity.IsAllDataRequested);
+        Assert.True(activity.Recorded);
+        Assert.Equal("Microsoft.AspNetCore", activity.Source.Name);
+        Assert.NotNull(activity.ParentId);
+        Assert.Equal(parentSpanId, activity.ParentSpanId);
+
+        await telemetry.Snapshot(activity, c => c.ScrubMember(Telemetry.Labels.UserPartyId));
+    }
 }

test/Altinn.App.Core.Tests/Internal/Pdf/PdfServiceTests.cs

@@ -86,7 +86,9 @@ public async Task ValidRequest_ShouldReturnPdf()
         );
 
         var httpClient = new HttpClient(delegatingHandler);
+        var logger = new Mock<ILogger<PdfGeneratorClient>>();
         var pdfGeneratorClient = new PdfGeneratorClient(
+            logger.Object,
             httpClient,
             _pdfGeneratorSettingsOptions,
             _platformSettingsOptions,
@@ -114,7 +116,9 @@ public async Task ValidRequest_PdfGenerationFails_ShouldThrowException()
         );
 
         var httpClient = new HttpClient(delegatingHandler);
+        var logger = new Mock<ILogger<PdfGeneratorClient>>();
         var pdfGeneratorClient = new PdfGeneratorClient(
+            logger.Object,
             httpClient,
             _pdfGeneratorSettingsOptions,
             _platformSettingsOptions,