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

namespace Microsoft.eShopOnContainers.Services.Ordering.API;

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public virtual IServiceProvider ConfigureServices(IServiceCollection services)
    {
        services
            .AddGrpc(options =>
            {
                options.EnableDetailedErrors = true;
            })
            .Services
            .AddApplicationInsights(Configuration)
            .AddCustomMvc()
            .AddHealthChecks(Configuration)
            .AddCustomDbContext(Configuration)
            .AddCustomSwagger(Configuration)
            .AddCustomIntegrations(Configuration)
            .AddCustomConfiguration(Configuration)
            .AddEventBus(Configuration)
            .AddCustomAuthentication(Configuration);
        //configure autofac

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

        container.RegisterModule(new MediatorModule());
        container.RegisterModule(new ApplicationModule(Configuration["ConnectionString"]));

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


    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))
        {
            loggerFactory.CreateLogger<Startup>().LogDebug("Using PATH BASE '{pathBase}'", pathBase);
            app.UsePathBase(pathBase);
        }

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

        app.UseRouting();
        app.UseCors("CorsPolicy");
        ConfigureAuth(app);

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapGrpcService<OrderingService>();
            endpoints.MapDefaultControllerRoute();
            endpoints.MapControllers();
            endpoints.MapGet("/_proto/", async ctx =>
            {
                ctx.Response.ContentType = "text/plain";
                using var fs = new FileStream(Path.Combine(env.ContentRootPath, "Proto", "basket.proto"), FileMode.Open, FileAccess.Read);
                using var sr = new StreamReader(fs);
                while (!sr.EndOfStream)
                {
                    var line = await sr.ReadLineAsync();
                    if (line != "/* >>" || line != "<< */")
                    {
                        await ctx.Response.WriteAsync(line);
                    }
                }
            });
            endpoints.MapHealthChecks("/hc", new HealthCheckOptions()
            {
                Predicate = _ => true,
                ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
            });
            endpoints.MapHealthChecks("/liveness", new HealthCheckOptions
            {
                Predicate = r => r.Name.Contains("self")
            });
        });

        ConfigureEventBus(app);
    }


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

        eventBus.Subscribe<UserCheckoutAcceptedIntegrationEvent, IIntegrationEventHandler<UserCheckoutAcceptedIntegrationEvent>>();
        eventBus.Subscribe<GracePeriodConfirmedIntegrationEvent, IIntegrationEventHandler<GracePeriodConfirmedIntegrationEvent>>();
        eventBus.Subscribe<OrderStockConfirmedIntegrationEvent, IIntegrationEventHandler<OrderStockConfirmedIntegrationEvent>>();
        eventBus.Subscribe<OrderStockRejectedIntegrationEvent, IIntegrationEventHandler<OrderStockRejectedIntegrationEvent>>();
        eventBus.Subscribe<OrderPaymentFailedIntegrationEvent, IIntegrationEventHandler<OrderPaymentFailedIntegrationEvent>>();
        eventBus.Subscribe<OrderPaymentSucceededIntegrationEvent, IIntegrationEventHandler<OrderPaymentSucceededIntegrationEvent>>();
    }

    protected virtual void ConfigureAuth(IApplicationBuilder app)
    {
        app.UseAuthentication();
        app.UseAuthorization();
    }
}

static class CustomExtensionsMethods
{
    public static IServiceCollection AddApplicationInsights(this IServiceCollection services, IConfiguration configuration)
    {
        services.AddApplicationInsightsTelemetry(configuration);
        services.AddApplicationInsightsKubernetesEnricher();

        return services;
    }

    public static IServiceCollection AddCustomMvc(this IServiceCollection services)
    {
        // Add framework services.
        services.AddControllers(options =>
            {
                options.Filters.Add(typeof(HttpGlobalExceptionFilter));
            })
            // Added for functional tests
            .AddApplicationPart(typeof(OrdersController).Assembly)
            .AddJsonOptions(options => options.JsonSerializerOptions.WriteIndented = true)
            .SetCompatibilityVersion(CompatibilityVersion.Version_3_0);

        services.AddCors(options =>
        {
            options.AddPolicy("CorsPolicy",
                builder => builder
                .SetIsOriginAllowed((host) => true)
                .AllowAnyMethod()
                .AllowAnyHeader()
                .AllowCredentials());
        });

        return services;
    }

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

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

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

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

        return services;
    }

    public static IServiceCollection AddCustomDbContext(this IServiceCollection services, IConfiguration configuration)
    {
        services.AddDbContext<OrderingContext>(options =>
                {
                    options.UseSqlServer(configuration["ConnectionString"],
                        sqlServerOptionsAction: sqlOptions =>
                        {
                            sqlOptions.MigrationsAssembly(typeof(Startup).GetTypeInfo().Assembly.GetName().Name);
                            sqlOptions.EnableRetryOnFailure(maxRetryCount: 15, maxRetryDelay: TimeSpan.FromSeconds(30), errorNumbersToAdd: null);
                        });
                },
                    ServiceLifetime.Scoped  //Showing explicitly that the DbContext is shared across the HTTP request scope (graph of objects started in the HTTP request)
                );

        services.AddDbContext<IntegrationEventLogContext>(options =>
        {
            options.UseSqlServer(configuration["ConnectionString"],
                                    sqlServerOptionsAction: sqlOptions =>
                                    {
                                        sqlOptions.MigrationsAssembly(typeof(Startup).GetTypeInfo().Assembly.GetName().Name);
                                        //Configuring Connection Resiliency: https://docs.microsoft.com/en-us/ef/core/miscellaneous/connection-resiliency 
                                        sqlOptions.EnableRetryOnFailure(maxRetryCount: 15, maxRetryDelay: TimeSpan.FromSeconds(30), errorNumbersToAdd: null);
                                    });
        });

        return services;
    }

    public static IServiceCollection AddCustomSwagger(this IServiceCollection services, IConfiguration configuration)
    {
        services.AddSwaggerGen(options =>
        {            
            options.SwaggerDoc("v1", new OpenApiInfo
            {
                Title = "eShopOnContainers - Ordering HTTP API",
                Version = "v1",
                Description = "The Ordering Service HTTP API"
            });
            options.AddSecurityDefinition("oauth2", new OpenApiSecurityScheme
            {
                Type = SecuritySchemeType.OAuth2,
                Flows = new OpenApiOAuthFlows()
                {
                    Implicit = new OpenApiOAuthFlow()
                    {
                        AuthorizationUrl = new Uri($"{configuration.GetValue<string>("IdentityUrlExternal")}/connect/authorize"),
                        TokenUrl = new Uri($"{configuration.GetValue<string>("IdentityUrlExternal")}/connect/token"),
                        Scopes = new Dictionary<string, string>()
                        {
                            { "orders", "Ordering API" }
                        }
                    }
                }
            });

            options.OperationFilter<AuthorizeCheckOperationFilter>();
        });

        return services;
    }

    public static IServiceCollection AddCustomIntegrations(this IServiceCollection services, IConfiguration configuration)
    {
        services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
        services.AddTransient<IIdentityService, IdentityService>();
        services.AddTransient<Func<DbConnection, IIntegrationEventLogService>>(
            sp => (DbConnection c) => new IntegrationEventLogService(c));

        services.AddTransient<IOrderingIntegrationEventService, OrderingIntegrationEventService>();

        if (configuration.GetValue<bool>("AzureServiceBusEnabled"))
        {
            services.AddSingleton<IServiceBusPersisterConnection>(sp =>
            {
                var serviceBusConnectionString = configuration["EventBusConnection"];

                var subscriptionClientName = configuration["SubscriptionClientName"];

                return new DefaultServiceBusPersisterConnection(serviceBusConnectionString);
            });
        }
        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);
            });
        }

        return services;
    }

    public static IServiceCollection AddCustomConfiguration(this IServiceCollection services, IConfiguration configuration)
    {
        services.AddOptions();
        services.Configure<OrderingSettings>(configuration);
        services.Configure<ApiBehaviorOptions>(options =>
        {
            options.InvalidModelStateResponseFactory = context =>
            {
                var problemDetails = new ValidationProblemDetails(context.ModelState)
                {
                    Instance = context.HttpContext.Request.Path,
                    Status = StatusCodes.Status400BadRequest,
                    Detail = "Please refer to the errors property for additional details."
                };

                return new BadRequestObjectResult(problemDetails)
                {
                    ContentTypes = { "application/problem+json", "application/problem+xml" }
                };
            };
        });

        return services;
    }

    public static IServiceCollection AddEventBus(this IServiceCollection services, IConfiguration configuration)
    {
        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>();
                string subscriptionName = configuration["SubscriptionClientName"];

                return new EventBusServiceBus(serviceBusPersisterConnection, logger,
                    eventBusSubcriptionsManager, iLifetimeScope, subscriptionName);
            });
        }
        else
        {
            services.AddSingleton<IEventBus, EventBusRabbitMQ>(sp =>
            {
                var subscriptionClientName = configuration["SubscriptionClientName"];
                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>();

        return services;
    }

    public static IServiceCollection AddCustomAuthentication(this IServiceCollection services, IConfiguration configuration)
    {
        // prevent from mapping "sub" claim to nameidentifier.
        JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Remove("sub");

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

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

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

        return services;
    }
}