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

using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Linq;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using Autofac;
using HealthChecks.UI.Client;
using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.ApplicationInsights.ServiceFabric;
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.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBus;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBus.Abstractions;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBusRabbitMQ;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBusServiceBus;
using Microsoft.eShopOnContainers.BuildingBlocks.IntegrationEventLogEF.Services;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Microsoft.Extensions.Logging;
using RabbitMQ.Client;
using Swashbuckle.AspNetCore.Swagger;
using Webhooks.API.Infrastructure;
using Webhooks.API.Services;

namespace Webhooks.API
{
    public class Startup
    {
        public IConfiguration Configuration { get; }

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


        public void ConfigureServices(IServiceCollection services)
        {
            services
                .AddAppInsight(Configuration)
                .AddCustomMVC(Configuration)
                .AddCustomDbContext(Configuration)
                .AddSwagger(Configuration)
                .AddCustomHealthCheck(Configuration)
                .AddHttpClientServices(Configuration)
                .AddIntegrationServices(Configuration)
                .AddEventBus(Configuration)
                .AddTransient<IIdentityService, IdentityService>()
                .AddTransient<IGrantUrlTesterService, GrantUrlTesterService>();
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddAzureWebAppDiagnostics();
            loggerFactory.AddApplicationInsights(app.ApplicationServices, LogLevel.Trace);

            var pathBase = Configuration["PATH_BASE"];

            if (!string.IsNullOrEmpty(pathBase))
            {
                loggerFactory.CreateLogger("init").LogDebug($"Using PATH BASE '{pathBase}'");
                app.UsePathBase(pathBase);
            }

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

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

            app.UseCors("CorsPolicy");

            app.UseMvcWithDefaultRoute();

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

            ConfigureEventBus(app);
        }

        protected virtual void ConfigureEventBus(IApplicationBuilder app)
        {
            var eventBus = app.ApplicationServices.GetRequiredService<IEventBus>();
            // eventBus.Subscribe<OrderStatusChangedToAwaitingValidationIntegrationEvent, OrderStatusChangedToAwaitingValidationIntegrationEventHandler>();
        }
    }

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

            return services;
        }

        public static IServiceCollection AddCustomMVC(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddMvc(options =>
            {
                options.Filters.Add(typeof(HttpGlobalExceptionFilter));
            })
                .SetCompatibilityVersion(CompatibilityVersion.Version_2_2)
                .AddControllersAsServices();

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

            return services;
        }

        public static IServiceCollection AddCustomDbContext(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddDbContext<WebhooksContext>(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: 10, maxRetryDelay: TimeSpan.FromSeconds(30), errorNumbersToAdd: null);
                                     });

                // Changing default behavior when client evaluation occurs to throw. 
                // Default in EF Core would be to log a warning when client evaluation is performed.
                options.ConfigureWarnings(warnings => warnings.Throw(RelationalEventId.QueryClientEvaluationWarning));
                //Check Client vs. Server evaluation: https://docs.microsoft.com/en-us/ef/core/querying/client-eval
            });

            return services;
        }

        public static IServiceCollection AddSwagger(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddSwaggerGen(options =>
            {
                options.DescribeAllEnumsAsStrings();
                options.SwaggerDoc("v1", new Swashbuckle.AspNetCore.Swagger.Info
                {
                    Title = "eShopOnContainers - Webhooks HTTP API",
                    Version = "v1",
                    Description = "The Webhooks Microservice HTTP API. This is a simple webhooks CRUD registration entrypoint",
                    TermsOfService = "Terms Of Service"
                });

                options.AddSecurityDefinition("oauth2", new OAuth2Scheme
                {
                    Type = "oauth2",
                    Flow = "implicit",
                    AuthorizationUrl = $"{configuration.GetValue<string>("IdentityUrlExternal")}/connect/authorize",
                    TokenUrl = $"{configuration.GetValue<string>("IdentityUrlExternal")}/connect/token",
                    Scopes = new Dictionary<string, string>()
                    {
                        { "webhooks", "Webhooks.API" }
                    }
                });

            });



            return services;
        }
        public static IServiceCollection AddEventBus(this IServiceCollection services, IConfiguration configuration)
        {
            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<OrderStatusChangedToAwaitingValidationIntegrationEventHandler>();

            return services;
        }

        public static IServiceCollection AddCustomHealthCheck(this IServiceCollection services, IConfiguration configuration)
        {
            var accountName = configuration.GetValue<string>("AzureStorageAccountName");
            var accountKey = configuration.GetValue<string>("AzureStorageAccountKey");

            var hcBuilder = services.AddHealthChecks();

            hcBuilder
                .AddCheck("self", () => HealthCheckResult.Healthy())
                .AddSqlServer(
                    configuration["ConnectionString"],
                    name: "WebhooksApiDb-check",
                    tags: new string[] { "webhooksdb" });

            return services;
        }

        public static IServiceCollection AddHttpClientServices(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();


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

            //InfinteTimeSpan -> See: https://github.com/aspnet/HttpClientFactory/issues/194
            services.AddHttpClient("extendedhandlerlifetime").SetHandlerLifetime(Timeout.InfiniteTimeSpan);

            //add http client services
            services.AddHttpClient("GrantClient")
                   .SetHandlerLifetime(TimeSpan.FromMinutes(5));
                   //.AddHttpMessageHandler<HttpClientAuthorizationDelegatingHandler>();

            return services;
        }

        public static IServiceCollection AddIntegrationServices(this IServiceCollection services, IConfiguration configuration)
        {
            services.AddTransient<Func<DbConnection, IIntegrationEventLogService>>(
                sp => (DbConnection c) => new IntegrationEventLogService(c));

            // services.AddTransient<ICatalogIntegrationEventService, CatalogIntegrationEventService>();

            if (configuration.GetValue<bool>("AzureServiceBusEnabled"))
            {
                services.AddSingleton<IServiceBusPersisterConnection>(sp =>
                {
                    var logger = sp.GetRequiredService<ILogger<DefaultServiceBusPersisterConnection>>();
                    var serviceBusConnection = new ServiceBusConnectionStringBuilder(configuration["EventBusConnection"]);
                    return new DefaultServiceBusPersisterConnection(serviceBusConnection, logger);
                });
            }
            else
            {
                services.AddSingleton<IRabbitMQPersistentConnection>(sp =>
                {
                    var logger = sp.GetRequiredService<ILogger<DefaultRabbitMQPersistentConnection>>();

                    var factory = new ConnectionFactory()
                    {
                        HostName = configuration["EventBusConnection"]
                    };

                    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;
        }
    }
}