Startup.cs

using HealthChecks.UI.Client;
using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.ApplicationInsights.ServiceFabric;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Authentication.OpenIdConnect;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.Diagnostics.HealthChecks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.eShopOnContainers.WebMVC.Services;
using Microsoft.eShopOnContainers.WebMVC.ViewModels;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Microsoft.Extensions.Logging;
using Polly;
using Polly.Extensions.Http;
using StackExchange.Redis;
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Net.Http;
using WebMVC.Infrastructure;
using WebMVC.Infrastructure.Middlewares;
using WebMVC.Services;

namespace Microsoft.eShopOnContainers.WebMVC
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the IoC container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddAppInsight(Configuration)
                    .AddHealthChecks(Configuration)
                    .AddCustomMvc(Configuration)
                    .AddHttpClientServices(Configuration)
                    //.AddHttpClientLogging(Configuration)  //Opt-in HttpClientLogging config
                    .AddCustomAuthentication(Configuration);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Clear();

            //loggerFactory.AddAzureWebAppDiagnostics();
            //loggerFactory.AddApplicationInsights(app.ApplicationServices, LogLevel.Trace);

            app.UseHealthChecks("/hc", new HealthCheckOptions()
            {
                Predicate = _ => true,
                ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
            });

            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            var pathBase = Configuration["PATH_BASE"];
            if (!string.IsNullOrEmpty(pathBase))
            {
                loggerFactory.CreateLogger<Startup>().LogDebug("Using PATH BASE '{PathBase}'", pathBase);
                app.UsePathBase(pathBase);
            }

            app.UseHealthChecks("/liveness", new HealthCheckOptions
            {
                Predicate = r => r.Name.Contains("self")
            });

            app.UseSession();
            app.UseStaticFiles();

            if (Configuration.GetValue<bool>("UseLoadTest"))
            {
                app.UseMiddleware<ByPassAuthMiddleware>();
            }

            app.UseAuthentication();

            WebContextSeed.Seed(app, env, loggerFactory);

            app.UseHttpsRedirection();
            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Catalog}/{action=Index}/{id?}");

                routes.MapRoute(
                    name: "defaultError",
                    template: "{controller=Error}/{action=Error}");
            });
        }
    }

    static class ServiceCollectionExtensions
    {

        public static IServiceCollection AddAppInsight(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddApplicationInsightsTelemetry(configuration);
            var orchestratorType = configuration.GetValue<string>("OrchestratorType");

            if (orchestratorType?.ToUpper() == "K8S")
            {
                // Enable K8s telemetry initializer
                services.AddApplicationInsightsKubernetesEnricher();
            }

            if (orchestratorType?.ToUpper() == "SF")
            {
                // Enable SF telemetry initializer
                services.AddSingleton<ITelemetryInitializer>((serviceProvider) =>
                    new FabricTelemetryInitializer());
            }

            return services;
        }

        public static IServiceCollection AddHealthChecks(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddHealthChecks()
                .AddCheck("self", () => HealthCheckResult.Healthy())
                .AddUrlGroup(new Uri(configuration["PurchaseUrlHC"]), name: "purchaseapigw-check", tags: new string[] { "purchaseapigw" })
                .AddUrlGroup(new Uri(configuration["MarketingUrlHC"]), name: "marketingapigw-check", tags: new string[] { "marketingapigw" })
                .AddUrlGroup(new Uri(configuration["IdentityUrlHC"]), name: "identityapi-check", tags: new string[] { "identityapi" });                
            
            return services;
        }

        public static IServiceCollection AddCustomMvc(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddOptions();
            services.Configure<AppSettings>(configuration);

            services.AddMvc()
                .SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

            services.AddSession();

            if (configuration.GetValue<string>("IsClusterEnv") == bool.TrueString)
            {
                services.AddDataProtection(opts =>
                {
                    opts.ApplicationDiscriminator = "eshop.webmvc";
                })
                .PersistKeysToRedis(ConnectionMultiplexer.Connect(configuration["DPConnectionString"]), "DataProtection-Keys");
            }
            return services;
        }

        // Adds all Http client services (like Service-Agents) using resilient Http requests based on HttpClient factory and Polly's policies 
        public static IServiceCollection AddHttpClientServices(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

            //register delegating handlers
            services.AddTransient<HttpClientAuthorizationDelegatingHandler>();
            services.AddTransient<HttpClientRequestIdDelegatingHandler>();

            //set 5 min as the lifetime for each HttpMessageHandler int the pool
            services.AddHttpClient("extendedhandlerlifetime").SetHandlerLifetime(TimeSpan.FromMinutes(5));

            //add http client services
            services.AddHttpClient<IBasketService, BasketService>()
                   .SetHandlerLifetime(TimeSpan.FromMinutes(5))  //Sample. Default lifetime is 2 minutes
                   .AddHttpMessageHandler<HttpClientAuthorizationDelegatingHandler>()
                   .AddPolicyHandler(GetRetryPolicy())
                   .AddPolicyHandler(GetCircuitBreakerPolicy());

            services.AddHttpClient<ICatalogService, CatalogService>()
                   .AddPolicyHandler(GetRetryPolicy())
                   .AddPolicyHandler(GetCircuitBreakerPolicy());

            services.AddHttpClient<IOrderingService, OrderingService>()
                 .AddHttpMessageHandler<HttpClientAuthorizationDelegatingHandler>()
                 .AddHttpMessageHandler<HttpClientRequestIdDelegatingHandler>()
                 .AddPolicyHandler(GetRetryPolicy())
                 .AddPolicyHandler(GetCircuitBreakerPolicy());

            services.AddHttpClient<ICampaignService, CampaignService>()
                .AddHttpMessageHandler<HttpClientAuthorizationDelegatingHandler>()
                .AddPolicyHandler(GetRetryPolicy())
                .AddPolicyHandler(GetCircuitBreakerPolicy());

            services.AddHttpClient<ILocationService, LocationService>()
               .AddHttpMessageHandler<HttpClientAuthorizationDelegatingHandler>()
               .AddPolicyHandler(GetRetryPolicy())
               .AddPolicyHandler(GetCircuitBreakerPolicy());

            //add custom application services
            services.AddTransient<IIdentityParser<ApplicationUser>, IdentityParser>();

            return services;
        }

        public static IServiceCollection AddHttpClientLogging(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddLogging(b =>
            {
                b.AddFilter((category, level) => true); // Spam the world with logs.

                // Add console logger so we can see all the logging produced by the client by default.
                b.AddConsole(c => c.IncludeScopes = true);

                // Add console logger
                b.AddDebug();
            });

            return services;
        }

        public static IServiceCollection AddCustomAuthentication(this IServiceCollection services, IConfiguration configuration)
        {
            var useLoadTest = configuration.GetValue<bool>("UseLoadTest");
            var identityUrl = configuration.GetValue<string>("IdentityUrl");
            var callBackUrl = configuration.GetValue<string>("CallBackUrl");

            // Add Authentication services          

            services.AddAuthentication(options =>
            {
                options.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
            })
            .AddCookie(setup=>setup.ExpireTimeSpan = TimeSpan.FromHours(2))
            .AddOpenIdConnect(options =>
            {
                options.SignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                options.Authority = identityUrl.ToString();
                options.SignedOutRedirectUri = callBackUrl.ToString();
                options.ClientId = useLoadTest ? "mvctest" : "mvc";
                options.ClientSecret = "secret";
                options.ResponseType = useLoadTest ? "code id_token token" : "code id_token";
                options.SaveTokens = true;
                options.GetClaimsFromUserInfoEndpoint = true;
                options.RequireHttpsMetadata = false;
                options.Scope.Add("openid");
                options.Scope.Add("profile");
                options.Scope.Add("orders");
                options.Scope.Add("basket");
                options.Scope.Add("marketing");
                options.Scope.Add("locations");
                options.Scope.Add("webshoppingagg");
                options.Scope.Add("orders.signalrhub");       
            });

            return services;
        }

        static IAsyncPolicy<HttpResponseMessage> GetRetryPolicy()
        {
            return HttpPolicyExtensions
              .HandleTransientHttpError()
              .OrResult(msg => msg.StatusCode == System.Net.HttpStatusCode.NotFound)
              .WaitAndRetryAsync(6, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));

        }
        static IAsyncPolicy<HttpResponseMessage> GetCircuitBreakerPolicy()
        {
            return HttpPolicyExtensions
                .HandleTransientHttpError()
                .CircuitBreakerAsync(5, TimeSpan.FromSeconds(30));
        }
    }
}