'Serilog.Extensions.Hosting.DiagnosticContext' while attempting to activate 'Serilog.AspNetCore.RequestLoggingMiddleware'

Question

When I run my program until Startup > Configure, it can create the log text file at C:\Serilog but it breaks at this line below:

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
            
        });

The error is:

Microsoft.AspNetCore.Hosting.Diagnostics[6]
      Application startup exception
System.InvalidOperationException: Unable to resolve service for type 'Serilog.Extensions.Hosting.DiagnosticContext' while attempting to activate 'Serilog.AspNetCore.RequestLoggingMiddleware'

This is my program.cs:

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Serilog;
using System;

namespace xxx
{
    public class Program
    {
        public static void Main(string[] args)
        {
           
            var configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();

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

            try
            {
                Log.Information("Application starting up");
                CreateHostBuilder(args).Build().Run();
            }
            catch (Exception ex)
            {
                Log.Fatal(ex, "The application failed to start correctly.");
            }
            finally
            {
                Log.CloseAndFlush();
            }
        }

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

and this is my startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.OpenApi.Models;
using Serilog;

namespace xxx
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseHttpsRedirection();

            app.UseSerilogRequestLogging();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
                
            });

        }
    }
}

and my appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "Serilog": {
    "Using": [],
    "MinimumLevel": {
      "Default": "Warning",
      "Override": {
        "Microsoft": "Warning",
        "System": "Warning"
      }
    },
    "Enrich": [ "FromLogContext", "WithMachineName", "WithProcessId", "WithThreadId" ],
    "WriteTo": [
      { "Name": "Console" },
      {
        "Name": "File",
        "Args": {
          "path": "C:\\SeriLog\\log.txt",
          "outputTemplate": "{Timestamp:G} {Message}{NewLine:1}{Exception:1}}"
        }
      },
      {
        "Name": "File",
        "Args": {
          "path": "C:\\SeriLog\\log.json",
          "formatter": "Serilog.Formatting.Json.JsonFormatter, Serilog"
        }
      },
      {
        "Name": "Seq",
        "Args": {
          "serverUrl": "http://localhost:8081"
        }
      }
    ]
  }
}

Answer 1

Seems that you are missing .UseSerilog inside Program. Here is my template for Program:

public class Program
{
    public static void Main(string[] args)
    {
        var webHost = CreateHostBuilder(args)
            .Build();

        // access any service from here by using webHost.Services.GetService<...
        
        Log.Information("Starting MyWebApp");

        // ... configure Serilog

        try
        {
          webHost.Run();
        }
        catch (Exception ex)
        {
          Log.Fatal(ex, "The application failed to start correctly.");
        }
        finally
        {
          Log.CloseAndFlush();
        }
    }

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

Answer 2

Upd 2022 In .Net 6 when you don't have Startup and Main classes it can be used in program.cs like:

try
{
    var builder = WebApplication.CreateBuilder(args);
    var logger = new LoggerConfiguration()
                        .ReadFrom.Configuration(builder.Configuration)
                        .Enrich.FromLogContext()
                        .CreateLogger();
    builder.Host.UseSerilog(logger);

    // more configuration

    var app = builder.Build();
    app.UseSerilogRequestLogging();

    // more configs
    app.Run();
}
catch (Exception ex)
{
    Log.Fatal(ex, "Unhandled exception");
}
finally
{
    Log.Information("Shut down complete");
    Log.CloseAndFlush();
}