eShopOnContainers/src/Services/Basket/Basket.API/Startup.cs

using Autofac;
using Autofac.Extensions.DependencyInjection;
using Basket.API.Infrastructure.Filters;
using Basket.API.Infrastructure.Middlewares;
using Basket.API.IntegrationEvents.EventHandling;
using Basket.API.IntegrationEvents.Events;
using HealthChecks.UI.Client;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Diagnostics.HealthChecks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.ServiceBus;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBus;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBus.Abstractions;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBusRabbitMQ;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBusServiceBus;
using Microsoft.eShopOnContainers.Services.Basket.API.Infrastructure.Repositories;
using Microsoft.eShopOnContainers.Services.Basket.API.IntegrationEvents.EventHandling;
using Microsoft.eShopOnContainers.Services.Basket.API.IntegrationEvents.Events;
using Microsoft.eShopOnContainers.Services.Basket.API.Model;
using Microsoft.eShopOnContainers.Services.Basket.API.Services;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using RabbitMQ.Client;
using StackExchange.Redis;
using System;
using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;

namespace Microsoft.eShopOnContainers.Services.Basket.API
{
    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 container.
        public IServiceProvider ConfigureServices(IServiceCollection services)
        {
            RegisterAppInsights(services);

            // Add framework services.
            services.AddMvc(options =>
                {
                    options.Filters.Add(typeof(HttpGlobalExceptionFilter));
                    options.Filters.Add(typeof(ValidateModelStateFilter));

                })
                .SetCompatibilityVersion(CompatibilityVersion.Version_3_0)
                .AddControllersAsServices();

            ConfigureAuthService(services);

            services.AddCustomHealthCheck(Configuration);

            services.Configure<BasketSettings>(Configuration);

            //By connecting here we are making sure that our service
            //cannot start until redis is ready. This might slow down startup,
            //but given that there is a delay on resolving the ip address
            //and then creating the connection it seems reasonable to move
            //that cost to startup instead of having the first request pay the
            //penalty.
            services.AddSingleton<ConnectionMultiplexer>(sp =>
            {
                var settings = sp.GetRequiredService<IOptions<BasketSettings>>().Value;
                var configuration = ConfigurationOptions.Parse(settings.ConnectionString, true);

                configuration.ResolveDns = true;

                return ConnectionMultiplexer.Connect(configuration);
            });


            if (Configuration.GetValue<bool>("AzureServiceBusEnabled"))
            {
                services.AddSingleton<IServiceBusPersisterConnection>(sp =>
                {
                    var logger = sp.GetRequiredService<ILogger<DefaultServiceBusPersisterConnection>>();

                    var serviceBusConnectionString = Configuration["EventBusConnection"];
                    var serviceBusConnection = new ServiceBusConnectionStringBuilder(serviceBusConnectionString);

                    return new DefaultServiceBusPersisterConnection(serviceBusConnection, logger);
                });
            }
            else
            {
                services.AddSingleton<IRabbitMQPersistentConnection>(sp =>
                {
                    var logger = sp.GetRequiredService<ILogger<DefaultRabbitMQPersistentConnection>>();

                    var factory = new ConnectionFactory()
                    {
                        HostName = Configuration["EventBusConnection"],
                        DispatchConsumersAsync = true
                    };

                    if (!string.IsNullOrEmpty(Configuration["EventBusUserName"]))
                    {
                        factory.UserName = Configuration["EventBusUserName"];
                    }

                    if (!string.IsNullOrEmpty(Configuration["EventBusPassword"]))
                    {
                        factory.Password = Configuration["EventBusPassword"];
                    }

                    var retryCount = 5;
                    if (!string.IsNullOrEmpty(Configuration["EventBusRetryCount"]))
                    {
                        retryCount = int.Parse(Configuration["EventBusRetryCount"]);
                    }

                    return new DefaultRabbitMQPersistentConnection(factory, logger, retryCount);
                });
            }

            RegisterEventBus(services);

            services.AddSwaggerGen(options =>
            {
                options.DescribeAllEnumsAsStrings();
                options.SwaggerDoc("v1", new OpenApi.Models.OpenApiInfo
                {
                    Title = "Basket HTTP API",
                    Version = "v1",
                    Description = "The Basket Service HTTP API"
                });

                options.AddSecurityDefinition("oauth2", new OpenApi.Models.OpenApiSecurityScheme
                {
                    Flows = new OpenApi.Models.OpenApiOAuthFlows()
                    {
                        Implicit = new OpenApi.Models.OpenApiOAuthFlow()
                        {
                            AuthorizationUrl = new Uri($"{Configuration.GetValue<string>("IdentityUrlExternal")}/connect/authorize"),
                            TokenUrl = new Uri($"{Configuration.GetValue<string>("IdentityUrlExternal")}/connect/token"),
                            Scopes = new Dictionary<string, string>()
                            {
                                { "basket", "Basket API" }
                            }
                        }
                    }
                });

            });

            services.AddCors(options =>
            {
                options.AddPolicy("CorsPolicy",
                    builder => builder
                    .SetIsOriginAllowed((host) => true)
                    .AllowAnyMethod()
                    .AllowAnyHeader()
                    .AllowCredentials());
            });
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddTransient<IBasketRepository, RedisBasketRepository>();
            services.AddTransient<IIdentityService, IdentityService>();

            services.AddOptions();

            var container = new ContainerBuilder();
            container.Populate(services);

            return new AutofacServiceProvider(container.Build());
        }


        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, ILoggerFactory loggerFactory)
        {
            //loggerFactory.AddAzureWebAppDiagnostics();
            //loggerFactory.AddApplicationInsights(app.ApplicationServices, LogLevel.Trace);

            var pathBase = Configuration["PATH_BASE"];
            if (!string.IsNullOrEmpty(pathBase))
            {
                app.UsePathBase(pathBase);
            }

            app.UseStaticFiles();
            app.UseCors("CorsPolicy");

            ConfigureAuth(app);

            app.UseRouting();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapHealthChecks("/hc", new HealthCheckOptions()
                {
                    Predicate = _ => true,
                    ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
                });
                endpoints.MapHealthChecks("/liveness", new HealthCheckOptions
                {
                    Predicate = r => r.Name.Contains("self")
                });
                endpoints.MapDefaultControllerRoute();
            });

            app.UseSwagger()
               .UseSwaggerUI(c =>
               {
                   c.SwaggerEndpoint($"{ (!string.IsNullOrEmpty(pathBase) ? pathBase : string.Empty) }/swagger/v1/swagger.json", "Basket.API V1");
                   c.OAuthClientId("basketswaggerui");
                   c.OAuthAppName("Basket Swagger UI");
               });

            ConfigureEventBus(app);

        }

        private void RegisterAppInsights(IServiceCollection services)
        {
            services.AddApplicationInsightsTelemetry(Configuration);
            services.AddApplicationInsightsKubernetesEnricher();
        }

        private void ConfigureAuthService(IServiceCollection services)
        {
            // prevent from mapping "sub" claim to nameidentifier.
            JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Clear();

            var identityUrl = Configuration.GetValue<string>("IdentityUrl");

            services.AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;

            }).AddJwtBearer(options =>
            {
                options.Authority = identityUrl;
                options.RequireHttpsMetadata = false;
                options.Audience = "basket";
            });
        }

        protected virtual void ConfigureAuth(IApplicationBuilder app)
        {
            if (Configuration.GetValue<bool>("UseLoadTest"))
            {
                app.UseMiddleware<ByPassAuthMiddleware>();
            }

            app.UseAuthentication();
            app.UseAuthorization();
        }

        private void RegisterEventBus(IServiceCollection services)
        {
            var subscriptionClientName = Configuration["SubscriptionClientName"];

            if (Configuration.GetValue<bool>("AzureServiceBusEnabled"))
            {
                services.AddSingleton<IEventBus, EventBusServiceBus>(sp =>
                {
                    var serviceBusPersisterConnection = sp.GetRequiredService<IServiceBusPersisterConnection>();
                    var iLifetimeScope = sp.GetRequiredService<ILifetimeScope>();
                    var logger = sp.GetRequiredService<ILogger<EventBusServiceBus>>();
                    var eventBusSubcriptionsManager = sp.GetRequiredService<IEventBusSubscriptionsManager>();

                    return new EventBusServiceBus(serviceBusPersisterConnection, logger,
                        eventBusSubcriptionsManager, subscriptionClientName, iLifetimeScope);
                });
            }
            else
            {
                services.AddSingleton<IEventBus, EventBusRabbitMQ>(sp =>
                {
                    var rabbitMQPersistentConnection = sp.GetRequiredService<IRabbitMQPersistentConnection>();
                    var iLifetimeScope = sp.GetRequiredService<ILifetimeScope>();
                    var logger = sp.GetRequiredService<ILogger<EventBusRabbitMQ>>();
                    var eventBusSubcriptionsManager = sp.GetRequiredService<IEventBusSubscriptionsManager>();

                    var retryCount = 5;
                    if (!string.IsNullOrEmpty(Configuration["EventBusRetryCount"]))
                    {
                        retryCount = int.Parse(Configuration["EventBusRetryCount"]);
                    }

                    return new EventBusRabbitMQ(rabbitMQPersistentConnection, logger, iLifetimeScope, eventBusSubcriptionsManager, subscriptionClientName, retryCount);
                });
            }

            services.AddSingleton<IEventBusSubscriptionsManager, InMemoryEventBusSubscriptionsManager>();

            services.AddTransient<ProductPriceChangedIntegrationEventHandler>();
            services.AddTransient<OrderStartedIntegrationEventHandler>();
        }

        private void ConfigureEventBus(IApplicationBuilder app)
        {
            var eventBus = app.ApplicationServices.GetRequiredService<IEventBus>();

            eventBus.Subscribe<ProductPriceChangedIntegrationEvent, ProductPriceChangedIntegrationEventHandler>();
            eventBus.Subscribe<OrderStartedIntegrationEvent, OrderStartedIntegrationEventHandler>();
        }
    }

    public static class CustomExtensionMethods
    {
        public static IServiceCollection AddCustomHealthCheck(this IServiceCollection services, IConfiguration configuration)
        {
            var hcBuilder = services.AddHealthChecks();

            hcBuilder.AddCheck("self", () => HealthCheckResult.Healthy());

            hcBuilder
                .AddRedis(
                    configuration["ConnectionString"],
                    name: "redis-check",
                    tags: new string[] { "redis" });

            if (configuration.GetValue<bool>("AzureServiceBusEnabled"))
            {
                hcBuilder
                    .AddAzureServiceBusTopic(
                        configuration["EventBusConnection"],
                        topicName: "eshop_event_bus",
                        name: "basket-servicebus-check",
                        tags: new string[] { "servicebus" });
            }
            else
            {
                hcBuilder
                    .AddRabbitMQ(
                        $"amqp://{configuration["EventBusConnection"]}",
                        name: "basket-rabbitmqbus-check",
                        tags: new string[] { "rabbitmqbus" });
            }

            return services;
        }
    }
}