eShopOnContainers/src/Services/Identity/Identity.API/Program.cs

using IdentityServer4.EntityFramework.DbContexts;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.eShopOnContainers.Services.Identity.API;
using Microsoft.eShopOnContainers.Services.Identity.API.Data;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Serilog;
using System;
using System.IO;

string Namespace = typeof(Startup).Namespace;
string AppName = Namespace.Substring(Namespace.LastIndexOf('.', Namespace.LastIndexOf('.') - 1) + 1);

var configuration = GetConfiguration();

Log.Logger = CreateSerilogLogger(configuration);

try
{
    Log.Information("Configuring web host ({ApplicationContext})...", AppName);
    var host = BuildWebHost(configuration, args);

    Log.Information("Applying migrations ({ApplicationContext})...", AppName);
    host.MigrateDbContext<PersistedGrantDbContext>((_, __) => { })
        .MigrateDbContext<ApplicationDbContext>((context, services) =>
        {
            var env = services.GetService<IWebHostEnvironment>();
            var logger = services.GetService<ILogger<ApplicationDbContextSeed>>();
            var settings = services.GetService<IOptions<AppSettings>>();

            new ApplicationDbContextSeed()
                .SeedAsync(context, env, logger, settings)
                .Wait();
        })
        .MigrateDbContext<ConfigurationDbContext>((context, services) =>
        {
            new ConfigurationDbContextSeed()
                .SeedAsync(context, configuration)
                .Wait();
        });

    Log.Information("Starting web host ({ApplicationContext})...", AppName);
    host.Run();

    return 0;
}
catch (Exception ex)
{
    Log.Fatal(ex, "Program terminated unexpectedly ({ApplicationContext})!", AppName);
    return 1;
}
finally
{
    Log.CloseAndFlush();
}

IWebHost BuildWebHost(IConfiguration configuration, string[] args) =>
    WebHost.CreateDefaultBuilder(args)
        .CaptureStartupErrors(false)
        .ConfigureAppConfiguration(x => x.AddConfiguration(configuration))
        .UseStartup<Startup>()
        .UseContentRoot(Directory.GetCurrentDirectory())
        .UseSerilog()
        .Build();

Serilog.ILogger CreateSerilogLogger(IConfiguration configuration)
{
    var seqServerUrl = configuration["Serilog:SeqServerUrl"];
    var logstashUrl = configuration["Serilog:LogstashgUrl"];
    return new LoggerConfiguration()
        .MinimumLevel.Verbose()
        .Enrich.WithProperty("ApplicationContext", AppName)
        .Enrich.FromLogContext()
        .WriteTo.Console()
        .WriteTo.Seq(string.IsNullOrWhiteSpace(seqServerUrl) ? "http://seq" : seqServerUrl)
        .WriteTo.Http(string.IsNullOrWhiteSpace(logstashUrl) ? "http://localhost:8080" : logstashUrl)
        .ReadFrom.Configuration(configuration)
        .CreateLogger();
}

IConfiguration GetConfiguration()
{
    var builder = new ConfigurationBuilder()
        .SetBasePath(Directory.GetCurrentDirectory())
        .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
        .AddEnvironmentVariables();

    var config = builder.Build();

    if (config.GetValue<bool>("UseVault", false))
    {
        builder.AddAzureKeyVault(
            $"https://{config["Vault:Name"]}.vault.azure.net/",
            config["Vault:ClientId"],
            config["Vault:ClientSecret"]);
    }

    return builder.Build();
}