DI: How to register Service, that needs parsed argument as parameter

[SvenBM]

Hi, i want to build a cli wrapper around an existing API. The API is instantiated with a static factory method which has a parameter called environment (PROD or TEST). This environment should be an option for the cli. How do i register the service properly to use it in Commands with DI?

[Matthiee]

Hi @SvenBM

I think I didn't understand the question correctly. Do you mean to register a service depending on the result of the CLI Option i.e. the PROD/TEST?

Maybe something like this is a solution?

Run

> wrapper.exe -e prod run
> Running API from PROD

Code

using MatthiWare.CommandLine;
using MatthiWare.CommandLine.Abstractions;
using MatthiWare.CommandLine.Abstractions.Command;
using MatthiWare.CommandLine.Core.Attributes;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Reflection;

namespace Question
{
    public enum ApiEnvironment
    {
        PROD,
        TEST
    }

    public class Options
    {
        [Name("e", "environment")]
        [Required]
        public ApiEnvironment Environment { get; set; }
    }

    public class Api
    {
        private readonly ApiEnvironment environment;

        private Api(ApiEnvironment environment)
        {
            this.environment = environment;
        }

        public static Api CreateApiFactory(ApiEnvironment environment)
            => new(environment);

        public void Run()
        {
            Console.WriteLine($"Running API from {environment}");
        }
    }

    public class RunCommand : Command<Options>
    {
        public override void OnConfigure(ICommandConfigurationBuilder builder)
        {
            builder.Name("run").Description("Runs the API");
        }

        public override void OnExecute(Options options)
        {
            var api = Api.CreateApiFactory(options.Environment);
            api.Run();
        }

        public class Program
        {
            static void Main(string[] args)
            {
                var services = ConfigureServices();

                var parser = services.BuildServiceProvider().GetRequiredService<ICommandLineParser<Options>>();

                parser.DiscoverCommands(Assembly.GetExecutingAssembly());

                parser.Parse(args);
            }

            static IServiceCollection ConfigureServices()
            {
                var services = new ServiceCollection();

                services.AddCommandLineParser<Options>();

                return services;
            }
        }
    }
}

[SvenBM]

Hey, thx for your fast reply. Yes, you got it right, despite that my API has an interface. But when i code it like this, i have to instantiate the API in every command (there are more than 1). It would by nicer if i could register the API's interface to the services and then inject it into the command - the DI-container should be responsible for creating instances. Do you see some way? Or is it prohibited by the parse-executeCommand-chain?

[Matthiee]

At the moment it is not possible to do this because the result of which API environment to use is only known after the service provider has already been built.