Adding process log enricher documentation

docs/core/enrichment/process-log-enricher.md

@@ -0,0 +1,65 @@
+---
+title: Process log enricher
+description: Learn how to use the process log enricher in .NET.
+ms.date: 10/10/2025
+---
+
+# Process log enricher
+
+The process enricher augments telemetry logs with process-specific information.
+
+You can register the enrichers in an IoC container. Then, all registered enrichers are picked up automatically by the respective telemetry instances, such as logs or metrics, where they enrich the telemetry information.
+
+## Usage
+
+To be able to use the process log enricher, first you need to enable enrichment like this:
+:::code language="csharp" source="snippets/enrichment/Program.cs" highlight="15":::
+
+then you can add the <xref:Microsoft.Extensions.DependencyInjection.ProcessEnricherServiceCollectionExtensions.AddProcessLogEnricher*> with default properties, like this:
+
+:::code language="csharp" source="snippets/enrichment/Program.cs" highlight="16":::
+
+or alternatively:
+
+```cs
+var hostApplicationBuilder = WebApplication.CreateBuilder();
+hostApplicationBuilder.Services.AddProcessLogEnricher();
+```
+
+Or, optionally, enable or disable individual options of the enricher using <xref:Microsoft.Extensions.DependencyInjection.ProcessEnricherServiceCollectionExtensions.AddProcessLogEnricher(Microsoft.Extensions.DependencyInjection.IServiceCollection,System.Action{Microsoft.Extensions.Diagnostics.Enrichment.ProcessLogEnricherOptions})>:
+
+```cs
+serviceCollection.AddProcessLogEnricher(options =>
+{
+    options.ThreadId = true;
+    options.ProcessId = true;
+});
+```
+
+You may also disable or enable individual options using `appsettings.json` file configuration, for example:
+
+```json
+{
+    "ProcessLogEnricherOptions": {
+        "ThreadId": true,
+        "ProcessId": true
+    }
+}
+```
+
+and apply it accordingly using <xref:Microsoft.Extensions.DependencyInjection.ProcessEnricherServiceCollectionExtensions.AddProcessLogEnricher(Microsoft.Extensions.DependencyInjection.IServiceCollection,Microsoft.Extensions.Configuration.IConfigurationSection)>:
+
+```cs
+serviceCollection.AddProcessLogEnricher(hostBuilder.Configuration.GetSection("ProcessLogEnricherOptions"));
+```
+
+## Default configuration
+
+Although default properties are supplied by the process enricher, you can customize them by initializing an instance of <xref:Microsoft.Extensions.Diagnostics.Enrichment.ProcessLogEnricherOptions> and providing it when registering the enricher.
+
+The default configuration for log enrichment is:
+
+| Property   | Default Value   | Description                                          |
+| -----------| ----------------|------------------------------------------------------|
+| `ProcessId`     | true            | If true, logs are enriched with the current process ID.        |
+| `ThreadId`      | false           | If true, logs are enriched with the current thread ID          |

docs/core/enrichment/snippets/enrichment/Enrichment.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Hosting" Version="9.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="9.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Telemetry" Version="9.9.0" />
+  </ItemGroup>
+
+</Project>

docs/core/enrichment/snippets/enrichment/Log.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation. All Rights Reserved.
+
+using Microsoft.Extensions.Logging;
+
+namespace Enrichment
+{
+    internal static partial class Log
+    {
+        [LoggerMessage(LogLevel.Information, "This is a sample log message")]
+        public static partial void LogSampleMessage(this ILogger logger);
+    }
+}

docs/core/enrichment/snippets/enrichment/Program.cs

@@ -0,0 +1,38 @@
+using System.Text.Json;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace Enrichment
+{
+    internal class Program
+    {
+        public static async Task Main()
+        {
+            var host = new HostBuilder()
+               .ConfigureLogging((hostingContext, loggingBuilder) =>
+               {
+                   loggingBuilder.EnableEnrichment();
+                   loggingBuilder.Services.AddProcessLogEnricher();
+                   loggingBuilder.AddJsonConsole(op =>
+                   {
+                       op.JsonWriterOptions = new JsonWriterOptions
+                       {
+                           Indented = true
+                       };
+                   });
+               });
+
+            var hostBuilder = host.Build();
+            var logger =
+               hostBuilder.Services
+                   .GetRequiredService<ILoggerFactory>()
+                   .CreateLogger<Program>();
+
+            logger.LogSampleMessage();
+
+            await hostBuilder.RunAsync();
+
+        }
+    }
+}

docs/navigate/tools-diagnostics/toc.yml

@@ -446,6 +446,10 @@ items:
             href: ../../core/diagnostics/distributed-tracing-collection-walkthroughs.md
           - name: Built-in activities
             href: ../../core/diagnostics/distributed-tracing-builtin-activities.md
+      - name: Enrichment
+        items:
+          - name: Process log enricher
+            href: ../../core/enrichment/process-log-enricher.md
       - name: Specialized diagnostics
         items:
           - name: Overview