eShopOnContainers/src/Services/Ordering/Ordering.BackgroundTasksHost/Program.cs

using Autofac.Extensions.DependencyInjection;
using Autofac;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using System;
using Ordering.BackgroundTasksHost.Configuration;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBusServiceBus;
using Microsoft.Azure.ServiceBus;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBusRabbitMQ;
using RabbitMQ.Client;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBus.Abstractions;
using Microsoft.eShopOnContainers.BuildingBlocks.EventBus;
using Ordering.BackgroundTasksHost.Tasks;

namespace Ordering.BackgroundTasksHost
{
    class Program
    {
        static void Main(string[] args)
        {
            using (var host = CreateHost(args))
            {
                host.Start();

                host.WaitForShutdown();
            }
        }

        static IHost CreateHost(string[] args)
        {
            var host = new HostBuilder()
                .ConfigureAppConfiguration((hostContext, configApp) =>
                {
                    configApp.AddEnvironmentVariables();
                    configApp.AddJsonFile("appsettings.json", optional: true);
                    configApp.AddJsonFile(
                        $"appsettings.{hostContext.HostingEnvironment.EnvironmentName}.json",
                        optional: true);
                    configApp.AddCommandLine(args);

                })
                .ConfigureServices(services =>
                {
                    var configuration = services.BuildServiceProvider()
                        .GetRequiredService<IConfiguration>();

                    services.AddOptions()
                        .Configure<BackgroundTaskSettings>(configuration)
                        .RegisterBus(configuration)
                        .RegisterHostedServices();

                })
                .UseServiceProviderFactory(new AutofacServiceProviderFactory())
                .Build();

            return host;
        }


    }

    class AutofacServiceProviderFactory
        : IServiceProviderFactory<ContainerBuilder>
    {
        public ContainerBuilder CreateBuilder(IServiceCollection services)
        {
            var containerBuilder = new ContainerBuilder();
            containerBuilder.Populate(services);

            return containerBuilder;
        }

        public IServiceProvider CreateServiceProvider(ContainerBuilder containerBuilder)
        {
            return new AutofacServiceProvider(containerBuilder.Build());
        }
    }

    static class ServiceCollectionExtensions
    {
        public static IServiceCollection RegisterBus(this IServiceCollection services, IConfiguration 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"]
                    };

                    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);
                });
            }


            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>();

            return services;
        }

        public static IServiceCollection RegisterHostedServices(this IServiceCollection services)
        {
            services.AddSingleton<IHostedService, GracePeriodManagerService>();

            return services;
        }
    }

}