Add better documentation for IResourceDetector and OltpExporter configuration

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/README.md

@@ -67,7 +67,14 @@ and environment variables.
 The `OtlpExporterOptions` type setters take precedence over the environment variables.
 
 This can be achieved by providing an `Action<OtlpExporterOptions>` delegate to the
-`AddOtlpExporter()` method.
+`AddOtlpExporter()` method or using `AddOptions<OtlpExporterOptions>()`.
+
+If additional services from the dependency injection are required, they can be configured like this:
+```csharp
+services.AddOptions<OtlpExporterOptions>().Configure<Service>((opts, svc) => {
+    // ...
+});
+```
 
 TODO: Show metrics specific configuration (i.e MetricReaderOptions).
 

src/OpenTelemetry.Extensions.Hosting/README.md

@@ -83,6 +83,28 @@ app.Run();
 A fully functional example can be found
 [here](https://github.com/open-telemetry/opentelemetry-dotnet/tree/main/examples/AspNetCore).
 
+### Resources
+To dynamically add resources at startup from the dependency injection you can provide an `IResourceDetector`.
+To make use of it add it to the dependency injection and they you can use the `ISerivceProvider` add it to OpenTelemetry:
+```csharp
+public class MyResourceDetector : IResourceDetector
+{
+    public Resource Detect()
+    {
+        return ResourceBuilder.CreateEmpty()
+            .AddService("your service name")
+            .Build();
+    }
+}
+
+services.AddSingleton<MyResourceDetector>();
+
+services.AddOpenTelemetry()
+    .ConfigureResource(builder =>
+        builder.AddDetector(sp => sp!.GetRequiredService<MyResourceDetector>()))
+    WithTracing(builder => builder.AddConsoleExporter());
+```
+
 ## Migrating from pre-release versions of OpenTelemetry.Extensions.Hosting
 
 Pre-release versions (all versions prior to 1.4.0) of

src/OpenTelemetry/.publicApi/net462/PublicAPI.Unshipped.txt

@@ -0,0 +1 @@
+OpenTelemetry.Resources.ResourceBuilder.AddDetector(System.Func<IServiceProvider, IResourceDetector!>! resourceDetectorFactory) -> OpenTelemetry.Resources.ResourceBuilder!

src/OpenTelemetry/.publicApi/net6.0/PublicAPI.Unshipped.txt

@@ -0,0 +1 @@
+OpenTelemetry.Resources.ResourceBuilder.AddDetector(System.Func<IServiceProvider, IResourceDetector!>! resourceDetectorFactory) -> OpenTelemetry.Resources.ResourceBuilder!

src/OpenTelemetry/.publicApi/netstandard2.0/PublicAPI.Unshipped.txt

@@ -0,0 +1 @@
+OpenTelemetry.Resources.ResourceBuilder.AddDetector(System.Func<IServiceProvider, IResourceDetector!>! resourceDetectorFactory) -> OpenTelemetry.Resources.ResourceBuilder!

src/OpenTelemetry/.publicApi/netstandard2.1/PublicAPI.Unshipped.txt

@@ -0,0 +1 @@
+OpenTelemetry.Resources.ResourceBuilder.AddDetector(System.Func<IServiceProvider, IResourceDetector!>! resourceDetectorFactory) -> OpenTelemetry.Resources.ResourceBuilder!

src/OpenTelemetry/CHANGELOG.md

@@ -18,6 +18,9 @@ Released 2023-Feb-10
   could be removed.
   ([#4174](https://github.com/open-telemetry/opentelemetry-dotnet/pull/4174))
 
+* Made the `IServiceProvider` variant of `AddDetector` publicly available.
+  ([#4230](https://github.com/open-telemetry/opentelemetry-dotnet/pull/4230))
+
 ## 1.4.0-rc.3
 
 Released 2023-Feb-01

src/OpenTelemetry/Resources/ResourceBuilder.cs

@@ -142,8 +142,7 @@ public ResourceBuilder AddDetector(IResourceDetector resourceDetector)
         /// </remarks>
         /// <param name="resourceDetectorFactory">Resource detector factory.</param>
         /// <returns>Supplied <see cref="ResourceBuilder"/> for call chaining.</returns>
-        // Note: This API may be made public if there is a need for it.
-        internal ResourceBuilder AddDetector(Func<IServiceProvider?, IResourceDetector> resourceDetectorFactory)
+        public ResourceBuilder AddDetector(Func<IServiceProvider?, IResourceDetector> resourceDetectorFactory)
         {
             Guard.ThrowIfNull(resourceDetectorFactory);