Owin.OpenIdConnect deadlock at cold start with IIS

We have some project, running on IIS. After cold start, sometimes we have deadlock, caused by method:

private static void OnSendingHeaderCallback(object state)
{
     AuthenticationHandler handler = (AuthenticationHandler)state;
     handler.ApplyResponseAsync().Wait();
}

We can’t do OpenIdConnect redirect and application freezes. Fixed only by iisreset

DotTrace show this

[Tratcher]

Related: https://github.com/aspnet/AspNetKatana/issues/51

For this to hang ApplyResponseAsync must actually go async. Most of the time it will complete sync, but at startup it needs to fetch the metadata document. https://github.com/aspnet/AspNetKatana/blob/e2b18ec84ceab7ffa29d80d89429c9988ab40144/src/Microsoft.Owin.Security.OpenIdConnect/OpenidConnectAuthenticationHandler.cs#L138

Possible workaround: Initialize and invoke OpenIdConnectOptions.ConfigurationManager at Startup to fetch the metadata before the first request (or load the metadata statically). See https://github.com/aspnet/AspNetKatana/blob/e2b18ec84ceab7ffa29d80d89429c9988ab40144/src/Microsoft.Owin.Security.OpenIdConnect/OpenIdConnectAuthenticationMiddleware.cs#L70-L102

[Tratcher]

Reading that closer, there’s no way for _config to become null after the constructor. If RetrieveMetadata threw in the constructor the entire object never would have been created.