Application Bootstrapping

A new experiment in improving the Steeltoe developer experience has been included in Steeltoe 3.1.0 that allows the configuration of most Steeltoe components with a single line of code in your application. The package is named Steeltoe.Bootstrap.Autoconfig, and it works by applying the HostBuilder extensions that are included in many Steeltoe packages to automatically wire up each of those components.

Applications running on .NET Core 3.1+ and .NET 5.0+ are supported. Get started by adding a reference to the Autoconfig package (you may want to add other Steeltoe references at this point too, see the table below for the full list of what's supported now):

<ItemGroup>
    <PackageReference Include="Steeltoe.Bootstrap.Autoconfig" Version="3.1.0-rc1" />
</ItemGroup>

After adding the NuGet reference(s), simply include .AddSteeltoe() like you see in this example and you're all set with the basic implementation:

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Steeltoe.Bootstrap.Autoconfig;

namespace WebApplication1
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                })
                .AddSteeltoe();
    }
}

Supported Steeltoe Packages

Steeltoe.Bootstrap.Autoconfig is not a meta-package. In order for a Steeltoe feature to be automatically bootstrapped in the application, the appropriate package must also be added as a reference. The following table describes the Steeltoe package that is required to light up a feature and any additional packages that may also be required:

Feature Description	Steeltoe Package	Additional Package Required
Config Server Configuration	Steeltoe.Extensions.Configuration.ConfigServerCore	N/A
Cloud Foundry Configuration	Steeltoe.Extensions.Configuration.CloudFoundryCore	N/A
Kubernetes Configuration	Steeltoe.Extensions.Configuration.KubernetesCore	N/A
Random Value Provider	Steeltoe.Extensions.Configuration.RandomValueBase	N/A
Placeholder Resolver	Steeltoe.Extensions.Configuration.PlaceholderCore	N/A
Connectors*	Steeltoe.Connector.ConnectorCore	Supported driver (MySQL, PostgreSQL, RabbitMQ, SQL Server, etc)
Dynamic Serilog	Steeltoe.Extensions.Logging.DynamicSerilogCore	N/A
Service Discovery	Steeltoe.Discovery.ClientBase or ClientCore	Desired client (Eureka, Consul, Kubernetes)
Actuators	Steeltoe.Management.EndpointCore	N/A
Actuators with Cloud Foundry support**	Steeltoe.Management.CloudFoundryCore	N/A
Actuators with Kubernetes support	Steeltoe.Management.KubernetesCore	N/A
Distributed Tracing	Steeltoe.Management.TracingCore	N/A
Cloud Foundry Container Identity	Steeltoe.Security.Authentication.CloudFoundryCore	N/A

* The Connection String Configuration provider is always added when ConnectorCore is referenced. Individual connector clients will only be configured if a corresponding supported driver NuGet package reference is also included.

** Cloud Foundry support is now included in Steeltoe.Management.EndpointCore. The Cloud Foundry Actuator package is not required and has been marked obsolete in 3.1.0.

Excluding Components

If you wish to exclude a component from the automatic bootstrap process, you may add the feature's assembly name to the exclusions list. One example where this feature would be desired is if you want to control the order configuration providers are added. This example shows how to provide the exclusions list:

public static IHostBuilder CreateHostBuilder(string[] args)
{
    List<string> myExclusions = new () { SteeltoeAssemblies.Steeltoe_Extensions_Configuration_ConfigServerCore };
    return Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        })
        .AddSteeltoe(myExclusions);
}

The static class SteeltoeAssemblies is public so that you can easily find the name of any specific assembly to exclude.

Logging Inside Config Providers

For some Steeltoe components, primarily configuration providers, providing a LoggerFactory is required to retrieve logs for debugging. Use the optional parameter to provide one as needed:

public static IHostBuilder CreateHostBuilder(string[] args)
{
    LoggerFactory loggerFactory = new (new List<ILoggerProvider> { new DebugLoggerProvider() });
    return Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        })
        .AddSteeltoe(loggerFactory: loggerFactory);
}

Limitations

• At this time, only Steeltoe libraries that can be configured from HostBuilder are supported.
• Most configuration providers require the *Core package variation and don't currently work with the *Base package

Feedback

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