From 589e17a97305c5ac15021be05b223e7931fa8b76 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Garc=C3=ADa=20Rubio?=
 <dgarciarubio.Software@gmail.com>
Date: Wed, 16 Oct 2024 10:36:07 +0200
Subject: [PATCH] Update Telemetry to read MeterOptions and
 ActivitySourceOptions from derived classes.

---
 .../WeatherForecastExtensions.cs              |  7 ++-
 .../ActivitySourceOptions.cs                  | 47 +++++++++++++++++++
 .../Telemetry.cs                              | 18 +++----
 3 files changed, 56 insertions(+), 16 deletions(-)
 create mode 100644 AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/ActivitySourceOptions.cs

diff --git a/AspNetCore.Examples.OpenTelemetry.Api/WeatherForecast/WeatherForecastExtensions.cs b/AspNetCore.Examples.OpenTelemetry.Api/WeatherForecast/WeatherForecastExtensions.cs
index 296a1ac..1c63f92 100644
--- a/AspNetCore.Examples.OpenTelemetry.Api/WeatherForecast/WeatherForecastExtensions.cs
+++ b/AspNetCore.Examples.OpenTelemetry.Api/WeatherForecast/WeatherForecastExtensions.cs
@@ -17,11 +17,10 @@ public static IEndpointRouteBuilder MapWeatherForecast(this IEndpointRouteBuilde
             "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
         };
 
-        endpoints.MapGet("/weatherforecast", (IWeatherForecastTelemetry telemetry) =>
+        endpoints.MapGet("/weather-forecast", (IWeatherForecastTelemetry telemetry) =>
         {
-            using var _ = telemetry.ActivitySource.StartActivity(name: "sample_activity", kind: ActivityKind.Internal);
-            telemetry.Logger.LogInformation("Requesting weather forecast");
-
+            using var activity = telemetry.ActivitySource.StartActivity(name: "weather_forecast.request", kind: ActivityKind.Internal);
+            
             var forecast = Enumerable.Range(1, 5).Select(index =>
                 new WeatherForecast
                 (
diff --git a/AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/ActivitySourceOptions.cs b/AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/ActivitySourceOptions.cs
new file mode 100644
index 0000000..f3e54c0
--- /dev/null
+++ b/AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/ActivitySourceOptions.cs
@@ -0,0 +1,47 @@
+namespace System.Diagnostics;
+
+/// <summary>
+/// Options for creating an <see cref="ActivitySource"/>.
+/// </summary>
+public class ActivitySourceOptions
+{
+    private string _name;
+
+    /// <summary>
+    /// The ActivitySource name.
+    /// </summary>
+    public string Name
+    {
+        get => _name;
+        set
+        {
+            if (value is null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            _name = value;
+        }
+    }
+
+    /// <summary>
+    /// The optional ActivitySource version.
+    /// </summary>
+    public string? Version { get; set; }
+
+    /// <summary>
+    /// The optional list of key-value pair tags associated with the ActivitySource.
+    /// </summary>
+    public IEnumerable<KeyValuePair<string, object?>>? Tags { get; set; }
+
+    /// <summary>
+    /// Constructs a new instance of <see cref="ActivitySourceOptions"/>.
+    /// </summary>
+    /// <param name="name">The ActivitySource name.</param>
+    public ActivitySourceOptions(string name)
+    {
+        Name = name;
+
+        Debug.Assert(_name is not null);
+    }
+}
diff --git a/AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/Telemetry.cs b/AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/Telemetry.cs
index ea7f39d..aeb75b5 100644
--- a/AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/Telemetry.cs
+++ b/AspNetCore.Examples.OpenTelemetry.TelemetryExtensions/Telemetry.cs
@@ -8,27 +8,21 @@ public class Telemetry<TCategoryName> : ITelemetry<TCategoryName>
 {
     private bool disposedValue;
 
-    internal static readonly string CategoryName = TypeNameHelper.GetTypeDisplayName(typeof(TCategoryName), includeGenericParameters: false, nestedTypeDelimiter: '.');
+    public static readonly string CategoryName = TypeNameHelper.GetTypeDisplayName(typeof(TCategoryName), includeGenericParameters: false, nestedTypeDelimiter: '.');
 
     public Telemetry(ILoggerFactory loggerFactory, IMeterFactory meterFactory)
     {
         Logger = loggerFactory.CreateLogger<TCategoryName>();
-        ActivitySource = new ActivitySource(CategoryName, Version);
-        Meter = meterFactory.Create(new MeterOptions(CategoryName)
-        {
-            Version = Version,
-            Scope = Scope,
-            Tags = Tags,
-        });
+        ActivitySource = new ActivitySource(ActivitySourceOptions.Name, ActivitySourceOptions.Version, ActivitySourceOptions.Tags);
+        Meter = meterFactory.Create(MeterOptions);
     }
 
     public ILogger<TCategoryName> Logger { get; }
     public ActivitySource ActivitySource { get; }
     public Meter Meter { get; }
 
-    protected virtual string? Version { get; }
-    protected virtual object? Scope { get; }
-    protected virtual IEnumerable<KeyValuePair<string, object?>>? Tags { get; }
+    protected virtual ActivitySourceOptions ActivitySourceOptions => new ActivitySourceOptions(CategoryName);
+    protected virtual MeterOptions MeterOptions => new MeterOptions(CategoryName);
 
     protected virtual void Dispose(bool disposing)
     {
@@ -48,4 +42,4 @@ public void Dispose()
         Dispose(disposing: true);
         GC.SuppressFinalize(this);
     }
-}
\ No newline at end of file
+}