Access to IServiceProvider/Startup used by TestServer

[phatcher]

Is it possible to get access to the IServiceProvider and/or the Startup class used by TestServer.

I'm trying to write some tests that confirm if service dependencies have been registered correctly in the underlying container.

[Eilon]

@javiercn - any idea on this?

[Tratcher]

TestServer.Host.Services?

[phatcher]

@Tratcher That looks good - I've got a problem where it works locally but in Azure I'm getting a socket error, "An attempt was made to access a socket in a way forbidden by its access permissions" but Azure doesn't think I'm anywhere near port exhaustion so I'm trying to see if some of the service lifetimes are borked some how.

[Tratcher]

That's a low level networking error, it shouldn't be related to anything in the service container. Is this Azure App Service using IIS & Kestrel? Did you modify Program.Main at all?

[phatcher]

It's a standard App Service Plan so I presume it's using Kestrel/IIS, the Program.Main is fairly standard...

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseApplicationInsights()
            .UseStartup<Startup>();
}

I'm using Simple.OData.Client, which is creates it's own HttpClient, to talk to my REST Api, it runs ok locally indefinitely but on Azure about 10 mins after I bounce the App Service Plan I start getting socket errors.

I was guessing at port exhaustion, but I'm not getting any Azure alerts and I don't know if I can find open connections via Kudu?

I'm trying to work around the multiple HttpClient creations by using AddHttpClient but this is complicated by needing to provide OAuth tokens on a per-user basis.

[javiercn]

@phatcher Why don't you write a unit test instead?

// arrange
var services = new ServiceCollection();
var startup = new Startup();

// act
startup.ConfigureServices(services);

// assert
Assert.Contains(services, sd => sd.ServiceType == typeof(MyType));

[Tratcher]

but this is complicated by needing to provide OAuth tokens on a per-user basis.

Sample code?

[phatcher]

@Tratcher What I'm not sure of at the moment is whether my client code, which wrappers Simple .OData.Client and was ported from .NET Framework and has been running for ~2 years, is sharing HttpClient instances inappropriately leading to the socket errors, so I'm trying to re-write using the AddHttpClient helpers...

The REST api is secured using OAuth 2.0, so each request from the web app has to have a bearer authentication token appropriate to the current user, this is delivered (eventually there's about 3 more layers in the way) by a class that uses the MsalSessionCache e.g.

private async Task<string> GetTokenAsync(ClaimsPrincipal principal = null, IList<string> scope = null)
{
    var context = httpContextAccessor.HttpContext;

    principal = principal ?? context.User;

    var scopes = openIdOptions.ApiScopes.Split(' ');
    var signedInUserId = principal.FindFirstValue(ClaimTypes.NameIdentifier);
    if (!string.IsNullOrEmpty(signedInUserId))
    {
	var userTokenCache = new MSALSessionCache(signedInUserId, context).GetMsalCacheInstance();
	var cca = new ConfidentialClientApplication(openIdOptions.ClientId, openIdOptions.Authority, openIdOptions.RedirectUri, new ClientCredential(openIdOptions.ClientSecret), userTokenCache, null);
	var user = cca.Users.FirstOrDefault();

	// Check as we can have a signed in user but cca.Users is null
	if (user != null)
	{
	    var result = await cca.AcquireTokenSilentAsync(scopes, user, openIdOptions.Authority, false);

	    // Prefer the access token but give back the id if not present
	    return result.AccessToken ?? result.IdToken;
	}
    }

    return null;
}

[phatcher]

@javiercn I have unit tests like this already but as this seems to be a server configuration issue I was trying to see how I could get to the service configuration that is actually running i.e. a form of integration testing of the configuration.

[Tratcher]

Your cache doesn't seem to cache anything since you recreate it on every call.

What do you do with the AccessToken once you have it? Add it to a request? How?

[phatcher]

@Tratcher It creates a cache for the duration of the request and handles token refresh - I didn't write this directly it's the recommended MS code for how to handle Azure B2C OAuth tokens; I agree that it looks odd but it seems to lookup/store the MSALSessionCache against the HttpContext. I am surprised that we are given sample code rather than a library for this since every app that wants to talk to a secured API needs this, and it would be good if it used one of the caches rather than being invoked per request.

It does seem to work in that I can see a single call out to MS to get the token on the first request on the page and then subsequent calls are cached.

Simple.OData.Client allows for a BeforeRequest delegate which allows me to put the token into the header, for the re-write I'm implementing this as a delegating handler which takes a IHttpContextAccessor to get to the current user - this is then passed in to the class that produces the token and I put it in the header in the same way.

[phatcher]

Ok, with the re-write the incidence of the socket error has greatly reduced but I am still getting some occasionally, is there anyway of seeing these with .NET Core as ServicePointManager doesn't work?

Happy to raise a different issue as the original query has been answered

[Tratcher]

Stack trace?