Duplicate error messages with Serilog ASP.NET Core

ASP.NET Core 5 Razor Pages using Serilog

UseStatusCodePagesWithReExecute works as expected and re-executes a page after it goes to my /CustomError page.

How to suppress Serilog logging of the 2nd call to the re-executed page?

password-postgres full sample

// program.cs
public static void Main(string[] args)
{
    Log.Logger = new LoggerConfiguration()
        // if only do warning, then will get duplicate error messages when an exception is thrown, then again when re-executed
        // we do get 2 error message per single error, but only 1 stack trace
        .MinimumLevel.Override("Microsoft.AspNetCore", LogEventLevel.Fatal)
        .Enrich.FromLogContext()
        .WriteTo.Console()
        .CreateLogger();

    try
    {
        Log.Information("Starting up");
        CreateHostBuilder(args).Build().Run();
    }
    catch (Exception ex)
    {
        Log.Fatal(ex, "Application start-up failed");
    }
    finally
    {
        Log.CloseAndFlush();
    }
}

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

and then

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        // snip
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/CustomError");
        }

        app.UseStaticFiles(); 

        // https://khalidabuhakmeh.com/handle-http-status-codes-with-razor-pages
        // https://andrewlock.net/retrieving-the-path-that-generated-an-error-with-the-statuscodepages-middleware/
        app.UseStatusCodePagesWithReExecute("/CustomError", "?statusCode={0}");

        app.UseRouting();

        // don't want request logging for static files so put this serilog middleware here in the pipeline
        app.UseSerilogRequestLogging(); // <- add this

        app.UseAuthentication();
        app.UseAuthorization();

        app.UseCookiePolicy(new CookiePolicyOptions { MinimumSameSitePolicy = SameSiteMode.Strict });

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

and then

// CustomError.cshtml.cs
[ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
[IgnoreAntiforgeryToken]
public class CustomErrorModel : PageModel
{
    public int? CustomStatusCode { get; set; }

    public void OnGet(int? statusCode = null)
    {
        var feature = HttpContext.Features.Get<IStatusCodeReExecuteFeature>();

        // a non 500 eg 404
        // this can be non page requests eg /js/site-chart.js
        // feature can be null when a 500 is thrown
        if (feature != null)
        {

            //Log.Warning($"Http Status code {statusCode} on {feature.OriginalPath}");
            CustomStatusCode = statusCode;
            return;
        }

        // a 500
        // relying on serilog to output the error
        //var exceptionHandlerPathFeature = HttpContext.Features.Get<IExceptionHandlerPathFeature>();

        // integration tests can call a page where the exceptionHandlerPathFeature can be null
        CustomStatusCode = 500;

        // somewhere else is emitting the Log.Error stacktracke
        //Log.Error($"Exception is {exceptionHandlerPathFeature.Error}");

        //OriginalPath = exceptionHandlerPathFeature.Path;
        //Exception exception = exceptionHandlerPathFeature.Error;
    }

    public void OnPost()
    {
        Log.Warning( "ASP.NET failure - maybe antiforgery. Caught by OnPost Custom Error. Sending a 400 to the user which is probable");
        Log.Warning("Need to take off minimumlevel override in Program.cs for more information");
        CustomStatusCode = 400;
    }
}

Duplicate log entries for errors eg 404 - ideally only want 1

Update

Thanks to Alan's answer below I've put the SerilogRequestLogging at the start of configure.

 public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 {

      app.UseSerilogRequestLogging(); 

      if (env.IsDevelopment())
      {
           app.UseDeveloperExceptionPage();
      }
      else
      {
           app.UseExceptionHandler("/CustomError");
      }

      app.UseStaticFiles(); 

      app.UseStatusCodePagesWithReExecute("/CustomError", "?statusCode={0}");

      // snip..
}

This gives 2 ERR messages in the log:

Which I'm fine with.

There is probably a way to merge the 2 ERR entries, but this is simple. Also the 2 entries are for different concepts. Requests and Exceptions.

It may be possible to give each log entry a RequestId as the boilerplate Error.cshtml.cs gives.

RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier;

But hey, this solution is good enough for me. Thanks Alan!