How to retrieve the args array after using AddCommandLine - .net-core

Question

I am working on a POC for a console application and I am struggling to retrieve the command line values from the configuration after using AddCommandLine in the set up.
csproj
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>netcoreapp3.1</TargetFramework>
</PropertyGroup>
Program class
public static class Program
{
public static async Task Main(string[] args)
{
Log.Logger = new LoggerConfiguration()
.Enrich.FromLogContext()
.WriteTo.Console()
.WriteTo.RollingFile("Logs//log.txt")
.CreateLogger();
await CreateHostBuilder(args)
.Build()
.RunAsync();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.UseSerilog()
.ConfigureAppConfiguration((hostingContext, config) =>
{
config.AddJsonFile("settings.json", true, true);
config.AddCommandLine(args);
})
.ConfigureServices((hostcontext, services) =>
{
services.AddHostedService<ConsoleApp>();
});
}
ConsoleApp class
public class ConsoleApp : IHostedService
{
private readonly IConfiguration config;
private readonly ILogger<ConsoleApp> log;
public ConsoleApp(IConfiguration configuration, ILogger<ConsoleApp> logger)
{
config = configuration;
log = logger;
}
public Task StartAsync(CancellationToken cancellationToken)
{
var t = config.GetSection("Args");
Parser.Default.ParseArguments<DeleteOptions>(t)
.WithParsed<DeleteOptions>()
.WithNotParsed();
foreach (var c in config.AsEnumerable())
{
log.LogInformation($"{c.Key, -15}:{c.Value}");
}
log.LogInformation($"Completing Start Task");
return Task.CompletedTask;
}
public Task StopAsync(CancellationToken cancellationToken)
{
log.LogInformation($"Complete End Task");
return Task.CompletedTask;
}
}
The Parser section before the foreach loop does not compile and the output from the loop does not print out any of the arguments I have added.
I am aware of the general advice that var someValue = Configuration.GetValue<int>("MySetting:SomeValue"); where the argument is --MySetting=SomeValue is the recommended way to retrieve cmd line values.
The values I am using as parameters are delete -e CI -t depchpolestar -l de-DE and when I look at my config object I see
which is why I think the line var t = config.GetSection("Args"); should retrieve the args array. I have also tried var t = config.GetValue<string[]>("Args"); but neither seems to work. It appears to me that index 4 of the configuration object is a string array keyed by "Args"
How do I retrieve the string array so I can pass it into CommandLineParser's ParseArguments method?
[Edit] One Solution:
I can now get the args passed through but it is not a particularly nice approach; If I construct the argument as --delete "-e CI -t depchpolestar -l de-DE" instead of delete -e CI -t depchpolestar -l de-DE and adding the following code to the ConsoleApp class:
var args = config.GetValue<string>("delete");
string[] arguments = null;
if(!string.IsNullOrEmpty(args))
{
var tempArgs = args.Split(" ");
arguments = new string[tempArgs.Length + 1];
arguments[0] = "delete";
for(int i = 0; i < tempArgs.Length; ++i)
{
arguments[i + 1] = tempArgs[i];
}
}
Parser.Default.ParseArguments<DeleteOptions>(arguments)
.WithParsed<DeleteOptions>(async c => await c.Dowork())
.WithNotParsed(HandleParseError);
execution hits the DoWork method. Good but DeleteOptions.cs defines a Verb and the intention is to add more commands. So more work to do but going the right way.
[Edit] I have also realised that I do not need to add the AddCommandLine() call as they are added by default.

Answer 1

ok it seemed that I over complicated this and ended up with this:
public static class Program
{
public static async Task Main(string[] args)
{
var builtHost = CreateHostBuilder(args).Build();
var console = builtHost.Services.GetService<ConsoleApp>();
await console.Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.UseSerilog()
.ConfigureAppConfiguration((hostingContext, config) =>
{
config.AddJsonFile("settings.json", true, true);
config.AddCommandLine(args);
})
.ConfigureServices((hostcontext, services) =>
{
services.AddTransient<ConsoleApp>();
});
}
and this as the run method in ConsoleApp:
public Task Run()
{
while (true)
{
var input = ReadFromConsole();
if (string.IsNullOrWhiteSpace(input))
{
continue;
}
else if (input.ToLower().Equals("exit"))
{
break;
}
else
{
Parser.Default.ParseArguments<DeleteOptions, ConcatOptions, DownloadOptions, ReportOptions>(input.Split(" "))
.WithParsed<DeleteOptions>(async options => await options.DoWork())
.WithParsed<ConcatOptions>(async options => await options.DoWork())
.WithParsed<DownloadOptions>(async options => await options.DoWork())
.WithParsed<ReportOptions>(async options => await options.DoWork())
.WithNotParsed(HandleParseError);
}
}
return Task.CompletedTask;
}
This works fine for allowing me to use it as an interactive console app. I do have a problem with the DI though. I have created an OptionsBase class which set up logging and I have done it this way as trying to add a parameter to any of the Options classes fails stating unable to find the parameterless constructor. So I am assuming that CommandLine requires default constructors to work. Gett ing a logger the way I have gives me multiple log files so I need to fix that.