Round #858

Configure structured logging using ILogger<T>. Show a service that injects ILogger<MyService> and writes a log scope around a unit of work, including a correlation id.

**Configuring Structured Logging using ILogger<T>** To configure structured logging using `ILogger<T>`, you can follow these steps: ### Step 1: Install Required NuGet Packages You will need to install the following NuGet packages: * `Microsoft.Extensions.Logging` * `Microsoft.Extensions.Logging.Console` * `Serilog` (optional, but recommended for structured logging) * `Serilog.Extensions.Logging` You can install these packages using the NuGet Package Manager or by running the following commands in the Package Manager Console: ```powershell Install-Package Microsoft.Extensions.Logging Install-Package Microsoft.Extensions.Logging.Console Install-Package Serilog Install-Package Serilog.Extensions.Logging ``` ### Step 2: Configure Logging in Program.cs In the `Program.cs` file, you can configure logging as follows: ```csharp using Microsoft.Extensions.Logging; using Serilog; using Serilog.Events; var builder = WebApplication.CreateBuilder(args); // Configure logging builder.Host.UseSerilog((hostContext, loggerConfig) => { loggerConfig .MinimumLevel.Override("Microsoft", LogEventLevel.Warning) .Enrich.FromLogContext() .WriteTo.Console(outputTemplate: "{Timestamp:yyyy-MM-dd HH:mm:ss} [{Level}] {CorrelationId} {Message}{NewLine}{Exception}"); }); // Add services to the container. builder.Services.AddControllers(); var app = builder.Build(); // Configure the HTTP request pipeline. if (app.Environment.IsDevelopment()) { app.UseDeveloperExceptionPage(); } app.UseHttpsRedirection(); app.UseAuthorization(); app.MapControllers(); app.Run(); ``` ### Step 3: Create a Service that Injects ILogger<MyService> Here's an example of a service that injects `ILogger<MyService>` and writes a log scope around a unit of work, including a correlation ID: ```csharp using Microsoft.Extensions.Logging; public class MyService { private readonly ILogger<MyService> _logger; public MyService(ILogger<MyService> logger) { _logger = logger; } public void DoWork(string correlationId) { using (_logger.BeginScope("{CorrelationId}", correlationId)) { _logger.LogInformation("Starting work"); // Simulate some work Thread.Sleep(1000); _logger.LogInformation("Finished work"); } } } ``` ### Step 4: Register the Service in the DI Container You can register the `MyService` in the DI container as follows: ```csharp builder.Services.AddTransient<MyService>(); ``` ### Step 5: Use the Service You can use the `MyService` in a controller or another service as follows: ```csharp [ApiController] [Route("api/[controller]")] public class MyController : ControllerBase { private readonly MyService _myService; public MyController(MyService myService) { _myService = myService; } [HttpGet] public IActionResult Get() { _myService.DoWork(Guid.NewGuid().ToString()); return Ok(); } } ``` This will write a log scope around the unit of work, including a correlation ID, to the console. The log output will look something like this: ``` 2024-09-16 14:30:00 [Information] 123e4567-e89b-12d3-a456-426655440000 Starting work 2024-09-16 14:30:01 [Information] 123e4567-e89b-12d3-a456-426655440000 Finished work ```

```csharp using Microsoft.Extensions.Logging; using System; public class MyService { private readonly ILogger<MyService> _logger; public MyService(ILogger<MyService> logger) { _logger = logger; } public void DoWork(string correlationId) { using (_logger.BeginScope("CorrelationId={CorrelationId}", correlationId)) { _logger.LogInformation("Starting unit of work"); // Simulate some work _logger.LogInformation("Doing some work"); _logger.LogInformation("Completed unit of work"); } } } public class Program { public static void Main(string[] args) { var serviceProvider = CreateServiceProvider(); var myService = serviceProvider.GetService<MyService>(); myService.DoWork("12345"); } private static IServiceProvider CreateServiceProvider() { var services = new ServiceCollection(); services.AddLogging(loggingBuilder => { loggingBuilder.AddConsole(options => { options.TimestampFormat = "[yyyy-MM-dd HH:mm:ss] "; }); }); services.AddTransient<MyService>(); return services.BuildServiceProvider(); } } ``` This implementation uses the `ILogger<T>` interface to inject a logger into the `MyService` class. The `DoWork` method creates a log scope using the `BeginScope` method, which includes a correlation ID. The log messages are written using the `LogInformation` method, and the scope is disposed of at the end of the `using` block. The `CreateServiceProvider` method sets up the logging configuration and registers the `MyService` class. The `Main` method demonstrates how to use the `MyService` class and write log messages with a correlation ID.