static void ExecuteAndUnload <T>(string modulePath, string resolvePath, Action <T> action, out WeakReference alcWeakRef) where T : class
{
// Create the unloadable HostAssemblyLoadContext
var alc = new ModuleAssemblyLoadContext(resolvePath);
// Load System.ComponentModel.TypeDescriptor to the ALC beforehand,
// as otherwise the internal caches in it will block unloading the ALC: https://github.com/dotnet/coreclr/issues/26271
// The netstandard assembly shim also needs to be loaded explicitly for the TypeDescriptor to be loaded.
var typeDescriptorAssemblyPath = typeof(TypeDescriptor).Assembly.Location;
alc.LoadFromAssemblyPath(typeDescriptorAssemblyPath);
var netstandardShimAssemblyPath = Path.Combine(Path.GetDirectoryName(typeDescriptorAssemblyPath), "netstandard.dll");
alc.LoadFromAssemblyPath(netstandardShimAssemblyPath);
// Create a weak reference to the AssemblyLoadContext that will allow us to detect
// when the unload completes.
alcWeakRef = new WeakReference(alc);
// Load the plugin assembly into the HostAssemblyLoadContext.
// NOTE: the assemblyPath must be an absolute path.
Assembly a = alc.LoadFromAssemblyPath(modulePath);
var assemblyResolverTool = new AssemblyResolverTool();
assemblyResolverTool.dependencyContext = DependencyContext.Load(a);
assemblyResolverTool.assemblyResolver = new CompositeCompilationAssemblyResolver
(new ICompilationAssemblyResolver[]
{
new AppBaseCompilationAssemblyResolver(Path.GetDirectoryName(modulePath)),
new ReferenceAssemblyPathResolver(),
new PackageCompilationAssemblyResolver()
});
alc.Resolving += assemblyResolverTool.OnResolving;
var module = ResolveTool.ResolveInstance <T>(a);
action(module);
// This initiates the unload of the HostAssemblyLoadContext. The actual unloading doesn't happen
// right away, GC has to kick in later to collect all the stuff.
alc.Resolving -= assemblyResolverTool.OnResolving;
alc.Unload();
}
static async Task ExecuteAndUnload <T>(string modulePath, string resolvePath, Func <T, Task> action, TaskCompletionSource <WeakReference> tcs) where T : class
{
try
{
var alc = new ModuleAssemblyLoadContext(resolvePath);
var typeDescriptorAssemblyPath = typeof(TypeDescriptor).Assembly.Location;
alc.LoadFromAssemblyPath(typeDescriptorAssemblyPath);
var netstandardShimAssemblyPath = Path.Combine(Path.GetDirectoryName(typeDescriptorAssemblyPath), "netstandard.dll");
alc.LoadFromAssemblyPath(netstandardShimAssemblyPath);
var alcWeakRef = new WeakReference(alc);
Assembly a = alc.LoadFromAssemblyPath(modulePath);
var assemblyResolverTool = new AssemblyResolverTool
{
dependencyContext = DependencyContext.Load(a),
assemblyResolver = new CompositeCompilationAssemblyResolver
(new ICompilationAssemblyResolver[]
{
new AppBaseCompilationAssemblyResolver(Path.GetDirectoryName(modulePath)),
new ReferenceAssemblyPathResolver(),
new PackageCompilationAssemblyResolver()
})
};
alc.Resolving += assemblyResolverTool.OnResolving;
var module = ResolveTool.ResolveInstance <T>(a);
await action(module);
alc.Resolving -= assemblyResolverTool.OnResolving;
alc.Unload();
tcs.TrySetResult(alcWeakRef);
}
catch (Exception ex)
{
tcs.TrySetException(ex);
}
}