ASP.NET Core web service does not load appsettings.json into configuration

Question

I have an ASP.NET Core 2.1 Web Application with Razor Pages which has AAD authentication information defined in the appsettings.json file (courtesy of the default application template - see below on how I got there). However, when trying to configure the authentication in Startup.cs the configuration does not have any of the config values from my appsettings.json. If I inspect the IConfiguration object in the debugger then it appears to only have the environment variable configurations:

Here's the Startup.ConfigureServices method where the issue lies:

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<CookiePolicyOptions>(options =>
    {
        // This lambda determines whether user consent for non-essential cookies is needed for a given request.
        options.CheckConsentNeeded = context => true;
        options.MinimumSameSitePolicy = SameSiteMode.None;
    });

    services.AddAuthentication(AzureADDefaults.AuthenticationScheme)
        .AddAzureAD(options =>
        {
            // This is from the default template. It should work, but the relevant settings aren't there so options isn't populated.
            this.Configuration.Bind("AzureAd", options);

            // This of course works fine
            options.Instance = "MyInstance";
            options.Domain = "MyDomain";
            options.TenantId = "MyTenantId";
            options.ClientId = "MyClientId";
            options.CallbackPath = "MyCallbackPath";
        });

    services.AddMvc(options =>
    {
        var policy = new AuthorizationPolicyBuilder()
            .RequireAuthenticatedUser()
            .Build();
        options.Filters.Add(new AuthorizeFilter(policy));
    })
    .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
}

And the service configuration in case it's important (note that this is being built on top of a service fabric stateless service):

protected override IEnumerable<ServiceInstanceListener> CreateServiceInstanceListeners()
{
    return new ServiceInstanceListener[]
    {
        new ServiceInstanceListener(serviceContext =>
            new KestrelCommunicationListener(serviceContext, "ServiceEndpoint", (url, listener) =>
            {
                ServiceEventSource.Current.ServiceMessage(serviceContext, $"Starting Kestrel on {url}");

                return new WebHostBuilder()
                            .UseKestrel(opt =>
                            {
                                int port = serviceContext.CodePackageActivationContext.GetEndpoint("ServiceEndpoint").Port;
                                opt.Listen(IPAddress.IPv6Any, port, listenOptions =>
                                {
                                    listenOptions.UseHttps(GetCertificateFromStore());
                                    listenOptions.NoDelay = true;
                                });
                            })
                            .ConfigureServices(
                                services => services
                                    .AddSingleton<StatelessServiceContext>(serviceContext))
                            .UseContentRoot(Directory.GetCurrentDirectory())
                            .UseStartup<Startup>()
                            .UseServiceFabricIntegration(listener, ServiceFabricIntegrationOptions.None)
                            .UseUrls(url)
                            .Build();
            }))
    };
}

To create this service, I used the wizard in VS2017. I selected an existing service fabric project (.sfproj) and chose Services > Add > New Service Fabric Service and chose Stateless ASP.NET Core [for .NET Framework], then on the next page I chose Web Application (the one with Razor Pages, not MVC) and clicked Change Authentication where I chose Work or School Accounts and entered my AAD info. The only changes I have made to this template were adding the code inside the call to AddAzureAD in Startup.ConfigureServices and setting the appsettings.json files to always be copied to the output directory.

Why doesn't the appsettings.json file get loaded into the configuration? As I understand, this is supposed to happen by default, but something seems to be missing...

Answer 1

WebHostBuilder doesn't load appsettings.json by default, you need to manually call AddJsonFile. For example:

return new WebHostBuilder()
            .UseKestrel(opt =>
            {
                //snip
            })
            .ConfigureAppConfiguration((builderContext, config) =>
            {
                config.AddJsonFile("appsettings.json", optional: false);
            })
            .ConfigureServices(
                services => services
                    .AddSingleton<StatelessServiceContext>(serviceContext))
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseStartup<Startup>()
            .UseServiceFabricIntegration(listener, ServiceFabricIntegrationOptions.None)
            .UseUrls(url)
            .Build();

Alternatively you can use WebHost.CreateDefaultBuilder which will load more defaults.

Answer 2

Another approach, would be to manually create the configuration via ConfigurationBuilder then use the UseConfiguration method.

var configuration = new ConfigurationBuilder()
     .SetBasePath(Directory.GetCurrentDirectory())
     .AddJsonFile("appsettings.json", false, true)
     .Build();

var host = new WebHostBuilder()
     .UseConfiguration(configuration)
     .UseKestrel()
     .UseStartup<Startup>();

The primary intent is core to provide a bit of flexibility when implementing, they often error on less is more. You have to explicitly say what you would like, that way the pipeline remains relatively small.