RawCoding: Plugin Architecture

// See https://aka.ms/new-console-template for more information

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.Loader;
using PluginSDK;


var app = new App();
await app.Run();

Console.WriteLine("done");

public class App
{
    public App()
    {
    }

    ~App()
    {
    }

    public async Task Run()
    {
        var weakReference = await Process();

        for (int i = 0; i < 10 && weakReference.IsAlive; i++)
        {
            GC.Collect();
            GC.WaitForPendingFinalizers();
        }
        Console.WriteLine($"unload successfully {!weakReference.IsAlive}");
    }

    // https://youtu.be/g4idDjBICO8
    // 13:15 - the reason for extracting into a method (... to use stack to clean up the resources)
    [MethodImpl(MethodImplOptions.NoInlining)]
    static async Task<WeakReference> Process()
    {
        // Console.WriteLine(Environment.CurrentDirectory);

        var fullPath = Path.GetFullPath(".\\Plugins\\FlexibleApp.Plugin.dll");

        // fails to work
        // var pluginFile = ".\\Plugins\\FlexibleApp.Plugin.dll";


        // note: by using this we are loading the assembly into the global context
        var assembly = Assembly.LoadFile(fullPath);

        // note: this will create a separated context just like appdomain where you can
        // create several domain and load assembly into them to keep thing separated
        var assemblyContext = new AssemblyLoadContext("plugins", isCollectible: true); // true: enable unload
        try
        {
            var assemblyNonGlobal = assemblyContext.LoadFromAssemblyPath(fullPath);
            // assemblyNonGlobal
            var entryPoint = assemblyNonGlobal.GetType("AppPlugin.EntryPoint");
            IPluginSdk plugin = (IPluginSdk)Activator.CreateInstance(entryPoint);
            await plugin.ExecuteAsync();
        }
        finally
        {
            // https://youtu.be/g4idDjBICO8
            // 11:00 - explain the unload
            assemblyContext.Unload();
        }

        return new WeakReference(assemblyContext);
    }
}

// source
// https://www.youtube.com/watch?v=g4idDjBICO8&ab_channel=RawCoding