Console application created using `System.CommandLine`

Program.cs

using System.CommandLine;
using Amazon;
using Amazon.S3;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

var profileOption = new Option<string>("--profile", getDefaultValue: () => "default", description: "The name of the profile to use to access AWS services.");

var regionOption = new Option<string>("--region", getDefaultValue: () => RegionEndpoint.EUWest1.SystemName, description: "The region where AWS services are located.");

var bucketNameOption = new Option<string>("--bucket-name", "The name of the S3 bucket where to fetch the files from") { IsRequired = true };

var prefixOption = new Option<string>("--prefix", description: "The prefix to use when fetching items from S3", getDefaultValue: () => "feeds/");

var openSearchNodeOption = new Option<Uri>("--node", description: "The address of the OpenSearch cluster to push documents into", getDefaultValue: () => new Uri("http://localhost:9200"));

var rootCommand = new RootCommand("Fetches files from S3 and loads them into an OpenSearch cluster")
{
    profileOption, regionOption,
    bucketNameOption, prefixOption,
    openSearchNodeOption
};

rootCommand.SetHandler(async (string profile, string region, string bucketName, string prefix, Uri node) =>
{
    var obj = new
    {
        AWS = new
        {
            Profile = profile,
            Region = region
        },
        Service1 = new
        {
            Bucket = bucketName,
            Prefix = prefix
        },
        Service2 = new
        {
            Nodes = new[] { node }
        }
    };

    var configuration = new ConfigurationBuilder()
        .AddObject(obj)
        .Build();

    var services = new ServiceCollection()
        .AddService3()
        .AddService1(configuration.GetSection("Service1"))
        .AddService2(configuration.GetSection("Service2"));

    services.AddLogging(logging => logging.AddConsole());

    services.AddAWSService<IAmazonS3>(configuration.GetAWSOptions());

    var serviceProvider = services.BuildServiceProvider();

    var logger = serviceProvider.GetRequiredService<ILogger<Program>>();

    var service1 = serviceProvider.GetRequiredService<IService1>();

    var service2 = serviceProvider.GetRequiredService<IService2>();

    var service3 = serviceProvider.GetRequiredService<IService3>();

    await service2.EnsureIndexesExist(default);

    await foreach (var feedName in service1.ListFeeds(default))
    {
        logger.LogInformation("Indexing {Feed}", feedName.FileName);
        await service3.IndexFeed(feedName, default);
    }
}, profileOption, regionOption, bucketNameOption, prefixOption, openSearchNodeOption);

await rootCommand.InvokeAsync(args);

Program2.cs

class Program
{
    static async Task Main(string[] args)
    {
        await BuildCommandLine()
            .UseHost(_ => Host.CreateDefaultBuilder(), host =>
            {
                IConfiguration configuration = null!;
                
                host.ConfigureAppConfiguration(builder =>
                {
                    // Add configuration providers
                    
                    configuration = builder.Build();
                });
                
                host.ConfigureServices(services =>
                {
                    services.AddAWSService<IAmazonS3>(configuration.GetAWSOptions());
                        
                    services
                        .AddService3()
                        .AddService1(configuration.GetSection("Service1"))
                        .AddService2(configuration.GetSection("Service2"));
                    

                });
            })
            .UseDefaults()
            .Build()
            .InvokeAsync(args);
    }

    static CommandLineBuilder BuildCommandLine()
    {
        var profileOption = new Option<string>("--profile", getDefaultValue: () => "default", description: "The name of the profile to use to access AWS services.");

        var regionOption = new Option<string>("--region", getDefaultValue: () => RegionEndpoint.EUWest1.SystemName, description: "The region where AWS services are located.");

        var bucketNameOption = new Option<string>("--bucket-name", "The name of the S3 bucket where to fetch the files from") { IsRequired = true };

        var prefixOption = new Option<string>("--prefix", description: "The prefix to use when fetching items from S3", getDefaultValue: () => "feeds/");

        var openSearchNodeOption = new Option<Uri>("--node", description: "The address of the OpenSearch cluster to push documents into", getDefaultValue: () => new Uri("http://localhost:9200"));

        var rootCommand = new RootCommand("Fetches files from S3 and loads them into an OpenSearch cluster")
        {
            profileOption, regionOption,
            bucketNameOption, prefixOption,
            openSearchNodeOption
        };

        rootCommand.Handler = CommandHandler.Create<IService1, IService2, IService3, ILogger>(RunAsync);

        return new CommandLineBuilder(rootCommand);
    }

    static async Task RunAsync(IService1 Service1, IService2 Service2, IService3 Service3, ILogger logger)
    {
         await Service2.EnsureIndexesExist(default);

         await foreach (var feedName in Service1.ListFeeds(default))
         {
             logger.LogInformation("Indexing {Feed}", feedName.FileName);
             await Service3.IndexFeed(feedName, default);
         }
    }
}