Hot-patching "deps.json" at runtime?

Question

I have a .NET 6.0 DLL that contains an Entity Framework Core DbContext to a SQL Server database.

If that assembly is referenced by the .NET 6.0 EXE and then called, everything works just fine.

However, if I try to use it in a plug-in concept and load the DLL via reflection like this:

var assembly = Assembly.LoadFrom("Plugin.dll");
var pluginType = assembly.GetExportedTypes()
  .Where(t => t.IsAssignableTo(typeof(IPlugin)))
  .First();
var plugin = (IPlugin)Activator.CreateInstance(pluginType);

Then I get

Microsoft.Data.SqlClient is not supported on this platform.

And the only difference is in the PluginHost.deps.json that now has no clue that at some point Microsoft.Data.SqlClient may get involved.

And I was wondering if there was some hot-load function to teach the EXE the dependencies of the DLL.

The whole test endeavor can be found on GitHub

Answer 1

I found the answer by this blog post and the nuget provided therein.

In essence: Add the nuget McMaster.NETCore.Plugins to your plugin host and then load the plugin like this:

var pluginInterfaceType = typeof(IPlugin); //must be shared between host and plugin
var loader = PluginLoader.CreateFromAssemblyFile(
    assemblyFile: fullPathAndFileNameToPlugin,
    sharedTypes: new[] { pluginInterfaceType });
var assembly = loader.LoadDefaultAssembly();
var pluginType = assembly.GetExportedTypes()
    .Where(t => t.IsAssignableTo(pluginInterfaceType))
    .First();
var plugin = (IPlugin)Activator.CreateInstance(pluginType);