appsettings.json

{
  "Serilog": {
    "Using": [
      "Serilog.Sinks.Console",
      "Serilog.Sinks.File",
      "NewRelic.LogEnrichers.Serilog"
    ],
    "MinimumLevel": "Debug",
    "Enrich": [ "WithNewRelicLogsInContext" ],
    "WriteTo": [
      {
        "Name": "File",
        "Args": {
          "path": "C:\\temp\\SerilogExample.log.json",
          "formatter": "NewRelic.LogEnrichers.Serilog.NewRelicFormatter, NewRelic.LogEnrichers.Serilog"
        }
      },
      {
        "Name": "Console",
        "Args": {
          "formatter": "NewRelic.LogEnrichers.Serilog.NewRelicFormatter, NewRelic.LogEnrichers.Serilog"
        }
      }
    ],
    "Properties": {
      "Application": "NewRelic Logging Serilog Example"
    }
  }
}

Program.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using NewRelic.LogEnrichers.Serilog;
using Serilog;
using Serilog.Events;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
namespace NewRelicLabs.WebAppLogging.SerilogInProcessForwarder
{
    public class Program
    {
        public static IConfiguration Configuration { get; } = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
            .AddJsonFile($"appsettings.{Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") ?? "Production"}.json", optional: true)
            .AddEnvironmentVariables()
            .Build();
        public static int Main(string[] args)
        {
            Log.Logger = new LoggerConfiguration()
                .ReadFrom.Configuration(Configuration)
                .CreateLogger();
            try
            {
                Log.Information("Starting web host");
                CreateHostBuilder(args).Build().Run();
                return 0;
            }
            catch (Exception ex)
            {
                Log.Fatal(ex, "Host terminated unexpectedly");
                return 1;
            }
            finally
            {
                Log.CloseAndFlush();
            }
        }
        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseSerilog()
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}