simplest k8s Main()

Program.cs

using System;
using System.Collections.Generic;

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

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

        public static IHostBuilder CreateHostBuilder(string[] args)
        {
            var switchMappings = new Dictionary<string, string>()
            {
                { "-s", "Start" },
                { "--start", "Start" }
            };

            return Host.CreateDefaultBuilder()
                .ConfigureAppConfiguration((hostingContext, config) =>
                {
                    config.AddKeyPerFile(directoryPath: "/app/secrets/shared", optional: true);
                    config.AddKeyPerFile(directoryPath: "/app/secrets/namespace", optional: true);

                    config.AddCommandLine(args, switchMappings);
                })
                //.ConfigureLogging(opt => { opt.AddConsole(c => { c.TimestampFormat = "[HH:mm:ss] "; }); }) // CORE31
                .ConfigureLogging(opt =>
                {
                    opt.AddSimpleConsole(consoleOpt =>
                    {
                        consoleOpt.TimestampFormat = "yyyy-MM-ddTHH:mm:ss.ff ";
                        //consoleOpt.UseUtcTimestamp = true; // not needed, k8s node local time will be UTC, and I'd prefer not to see UTC when running on Win10/WSL
                    });
                })
                .ConfigureServices((hostContext, services) =>
                {
                    new Startup(hostContext.Configuration)
                        .ConfigureServices(services);
                });
    }

    public record Startup(IConfiguration Configuration)
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<LoaderOptions>(Configuration);
            services.AddDbContextFactory<Models.AppSqlContext>(options =>
            {
                options.UseSqlServer(Configuration.GetConnectionString("AppSql"), sqlOptions =>
                {
                    sqlOptions.EnableRetryOnFailure(3);
                });
            });

            services.AddHostedService<Worker>();
        }
    }
}