addConsulExtension.cs

public static IServiceCollection AddConsul(this IServiceCollection serviceCollection)
{
    IConfiguration configuration;
    using (var serviceProvider = serviceCollection.BuildServiceProvider())
    {
        configuration = serviceProvider.GetService<IConfiguration>();
    }
    ConsulOptions consulConfigOptions = configuration.GetOptions<ConsulOptions>("Consul");

    serviceCollection.Configure<ConsulOptions>(configuration.GetSection("Consul"));
    serviceCollection.AddTransient<IConsulServices, ConsulServices>();
    serviceCollection.AddHttpClient<IConsulHttpClient, ConsulHttpClient>();

    return serviceCollection.AddSingleton<IConsulClient>(c => new ConsulClient(cfg =>
    {
        if (!string.IsNullOrEmpty(consulConfigOptions.Host))
        {
            cfg.Address = new Uri(consulConfigOptions.Host);
        }
    }));
}

public static string UseConsul(this IApplicationBuilder app)
{
    using (var scope = app.ApplicationServices.CreateScope())
    {
        var Iconfig = scope.ServiceProvider.GetService<IConfiguration>();

        var config = Iconfig.GetOptions<ConsulOptions>("Consul");
        var appOptions = Iconfig.GetOptions<AppOptions>("App");

        if (!config.Enabled)
            return String.Empty;

        Guid serviceId = Guid.NewGuid();
        string consulServiceID = $"{config.Service}:{serviceId}";

        var client = scope.ServiceProvider.GetService<IConsulClient>();

        var consulServiceRistration = new AgentServiceRegistration
        {
            Name = config.Service,
            ID = consulServiceID,
            Address = config.Address,
            Port = config.Port
        };

        client.Agent.ServiceRegister(consulServiceRistration);

        return consulServiceID;
    }
}