Logging every request to a shared Log File from multiple IIS instances

Question

I'm working on an ASP .NET Core 3.1 Web API project and encountering an issue with Serilog. The logs are written to the file only after the first request is made post-startup.

Here's a simplified version of my Program.cs

public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureSerilog()
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }

The ConfigureSerilog method is defined in a static class:

    public static class SerilogConfig
    {
        public static IHostBuilder ConfigureSerilog(this IHostBuilder builder)
        {
            Directory.SetCurrentDirectory(AppDomain.CurrentDomain.BaseDirectory);
            Directory.CreateDirectory("Logs");

            var configuration = new ConfigurationBuilder()
                .AddJsonFile("appsettings.Serilog.json", optional: false, reloadOnChange: true)
                .Build();

            Log.Logger = new LoggerConfiguration()
                .ReadFrom.Configuration(configuration)
                .Enrich.FromLogContext()
                .CreateLogger();

            builder.UseSerilog();

            return builder;
        }
    }

In my appsettings.Serilog.json, I've set shared to true since multiple IIS instances will log to the same file:

{
  "Serilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft": "Warning",
        "System": "Warning"
      }
    },
    "Using": [
      "Serilog.Sinks.File"
    ],
    "WriteTo": [
      {
        "Name": "File",
        "Args": {
          "Path": "./Logs/log.log",
          "shared": "true",
          "RollingInterval": "Day",
          "RetainedFileCountLimit": null,
          "formatter": {
            "type": "Serilog.Templates.ExpressionTemplate, Serilog.Expressions",
            "template": "[{@t:yyyy-MM-dd HH:mm:ss} {@l:u3}] {@m}\n{@x}"
          }
        }
      }
    ]
  }
}

How can I properly configure Serilog to ensure that every request from every IIS instance is logged to a single shared file without conflicts?

ideally you shouldn't write to the same file by multiple processes - merge after the fact! — Daniel A. White
– Daniel A. White, Commented Jun 3, 2024 at 18:23

Jerry Fu · Accepted Answer · 2024-06-05 06:30:46Z

0

You could consider using RabbitMQ to write to queue. This will cetainly avoid conflict. You could create an applcation to consume the queue and write to file one by one.
Write to rabbitmq: https://github.com/ArieGato/serilog-sinks-rabbitmq?tab=readme-ov-file#configuration-via-code
Read message from rabbitmq: https://www.rabbitmq.com/tutorials/tutorial-three-dotnet#putting-it-all-together

answered Jun 5, 2024 at 6:30

Jerry Fu

9,7481 gold badge7 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Logging every request to a shared Log File from multiple IIS instances

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related