Blazor - rendering metrics and tracing

src/Components/Components/src/ComponentsActivitySource.cs

@@ -0,0 +1,177 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics;
+
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// This is instance scoped per renderer
+/// </summary>
+internal class ComponentsActivitySource
+{
+    internal const string Name = "Microsoft.AspNetCore.Components";
+    internal const string OnCircuitName = $"{Name}.CircuitStart";
+    internal const string OnRouteName = $"{Name}.RouteChange";
+    internal const string OnEventName = $"{Name}.Event";
+
+    private ActivityContext _httpContext;
+    private ActivityContext _circuitContext;
+    private string? _circuitId;
+    private ActivityContext _routeContext;
+
+    private ActivitySource ActivitySource { get; } = new ActivitySource(Name);
+
+    public static ActivityContext CaptureHttpContext()
+    {
+        var parentActivity = Activity.Current;
+        if (parentActivity is not null && parentActivity.OperationName == "Microsoft.AspNetCore.Hosting.HttpRequestIn" && parentActivity.Recorded)
+        {
+            return parentActivity.Context;
+        }
+        return default;
+    }
+
+    public Activity? StartCircuitActivity(string circuitId, ActivityContext httpContext)
+    {
+        _circuitId = circuitId;
+
+        var activity = ActivitySource.CreateActivity(OnCircuitName, ActivityKind.Server, parentId: null, null, null);
+        if (activity is not null)
+        {
+            if (activity.IsAllDataRequested)
+            {
+                if (_circuitId != null)
+                {
+                    activity.SetTag("circuit.id", _circuitId);
+                }
+                if (httpContext != default)
+                {
+                    activity.AddLink(new ActivityLink(httpContext));
+                }
+            }
+            activity.DisplayName = $"Circuit {circuitId ?? ""}";
+            activity.Start();
+            _circuitContext = activity.Context;
+        }
+        return activity;
+    }
+
+    public void FailCircuitActivity(Activity? activity, Exception ex)
+    {
+        _circuitContext = default;
+        if (activity != null && !activity.IsStopped)
+        {
+            activity.SetTag("error.type", ex.GetType().FullName);
+            activity.SetStatus(ActivityStatusCode.Error);
+            activity.Stop();
+        }
+    }
+
+    public Activity? StartRouteActivity(string componentType, string route)
+    {
+        if (_httpContext == default)
+        {
+            _httpContext = CaptureHttpContext();
+        }
+
+        var activity = ActivitySource.CreateActivity(OnRouteName, ActivityKind.Server, parentId: null, null, null);
+        if (activity is not null)
+        {
+            if (activity.IsAllDataRequested)
+            {
+                if (_circuitId != null)
+                {
+                    activity.SetTag("circuit.id", _circuitId);
+                }
+                if (componentType != null)
+                {
+                    activity.SetTag("component.type", componentType);
+                }
+                if (route != null)
+                {
+                    activity.SetTag("route", route);
+                }
+                if (_httpContext != default)
+                {
+                    activity.AddLink(new ActivityLink(_httpContext));
+                }
+                if (_circuitContext != default)
+                {
+                    activity.AddLink(new ActivityLink(_circuitContext));
+                }
+            }
+
+            activity.DisplayName = $"Route {route ?? "[unknown path]"} -> {componentType ?? "[unknown component]"}";
+            activity.Start();
+            _routeContext = activity.Context;
+        }
+        return activity;
+    }
+
+    public Activity? StartEventActivity(string? componentType, string? methodName, string? attributeName)
+    {
+        var activity = ActivitySource.CreateActivity(OnEventName, ActivityKind.Server, parentId: null, null, null);
+        if (activity is not null)
+        {
+            if (activity.IsAllDataRequested)
+            {
+                if (_circuitId != null)
+                {
+                    activity.SetTag("circuit.id", _circuitId);
+                }
+                if (componentType != null)
+                {
+                    activity.SetTag("component.type", componentType);
+                }
+                if (methodName != null)
+                {
+                    activity.SetTag("component.method", methodName);
+                }
+                if (attributeName != null)
+                {
+                    activity.SetTag("attribute.name", attributeName);
+                }
+                if (_httpContext != default)
+                {
+                    activity.AddLink(new ActivityLink(_httpContext));
+                }
+                if (_circuitContext != default)
+                {
+                    activity.AddLink(new ActivityLink(_circuitContext));
+                }
+                if (_routeContext != default)
+                {
+                    activity.AddLink(new ActivityLink(_routeContext));
+                }
+            }
+
+            activity.DisplayName = $"Event {attributeName ?? "[unknown attribute]"} -> {componentType ?? "[unknown component]"}.{methodName ?? "[unknown method]"}";
+            activity.Start();
+        }
+        return activity;
+    }
+
+    public static void FailEventActivity(Activity? activity, Exception ex)
+    {
+        if (activity != null && !activity.IsStopped)
+        {
+            activity.SetTag("error.type", ex.GetType().FullName);
+            activity.SetStatus(ActivityStatusCode.Error);
+            activity.Stop();
+        }
+    }
+
+    public static async Task CaptureEventStopAsync(Task task, Activity? activity)
+    {
+        try
+        {
+            await task;
+            activity?.Stop();
+        }
+        catch (Exception ex)
+        {
+            FailEventActivity(activity, ex);
+        }
+    }
+}