Shuttle.Core.Pipelines 12.0.0

.NET Standard 2.0
dotnet add package Shuttle.Core.Pipelines --version 12.0.0
NuGet\Install-Package Shuttle.Core.Pipelines -Version 12.0.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="Shuttle.Core.Pipelines" Version="12.0.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add Shuttle.Core.Pipelines --version 12.0.0
#r "nuget: Shuttle.Core.Pipelines, 12.0.0"
#r directive can be used in F# Interactive, C# scripting and .NET Interactive. Copy this into the interactive tool or source code of the script to reference the package.
// Install Shuttle.Core.Pipelines as a Cake Addin
#addin nuget:?package=Shuttle.Core.Pipelines&version=12.0.0

// Install Shuttle.Core.Pipelines as a Cake Tool
#tool nuget:?package=Shuttle.Core.Pipelines&version=12.0.0

Shuttle.Core.Pipelines

PM> Install-Package Shuttle.Core.Pipelines

Observable event-based pipelines based broadly on pipes and filters.

Configuration

In order to more easily make use of pipelines an implementation of the IPipelineFactory should be used. The following will register the PipelineFactory implementation:

services.AddPipelineProcessing(builder => {
    builder.AddAssembly(assembly);
});

This will register the IPipelineFactory and, using the builder, add all IPipeline and IPipelineObserver implementations as Transient. The pipeline instances are re-used as they are kept in a pool.

Since pipelines are quite frequently extended by adding observers a module may be added that adds the relevant observers to a pipeline on creation:

services.AddPipelineModule<T>();
services.AddPipelineModule(type);

The way this is accomplished is having a module such as the following:

public class SomeModule
{
    private readonly Type _pipelineType = typeof(InterestingPipeline);

    public SomeModule(IPipelineFactory pipelineFactory)
    {
        Guard.AgainstNull(pipelineFactory, nameof(pipelineFactory));

        pipelineFactory.PipelineCreated += PipelineCreated;
    }

    private void PipelineCreated(object sender, PipelineEventArgs e)
    {
        var pipelineType = ;

        if (e.Pipeline.GetType() != _pipelineType
        {
            return;
        }

        e.Pipeline.RegisterObserver(new SomeObserver());
    }
}

The above module could be added to the IServiceCollection as follows:

services.AddPipelineModule<SomeModule>();

Overview

A Pipeline is a variation of the pipes and filters pattern and consists of 1 or more stages that each contain one or more events. When the pipeline is executed each event in each stage is raised in the order that they were registered. One or more observers should be registered to handle the relevant event(s).

Each Pipeline always has its own state that is simply a name/value pair with some convenience methods to get and set/replace values. The State class will use the full type name of the object as a key should none be specified:

var state = new State();
var list = new List<string> {"item-1"};

state.Add(list); // key = System.Collections.Generic.List`1[[System.String...]]
state.Add("my-key", "my-key-value");

Console.WriteLine(state.Get<List<string>>()[0]);
Console.Write(state.Get<string>("my-key"));

Example

Events should derive from PipelineEvent.

We will use the following events:

public class OnAddCharacterA : PipelineEvent
{
}

public class OnAddCharacter : PipelineEvent
{
	public char Character { get; private set; }

	public OnAddCharacter(char character)
	{
		Character = character;
	}
}

The OnAddCharacterA event represents a very explicit event whereas with the OnAddCharacter event one can specify some data. In this case the character to add.

In order for the pipeline to process the events we will have to define one or more observers to handle the events. We will define only one for this sample but we could very easily add another that will handle one or more of the same, or other, events:

    public class CharacterPipelineObserver : 
        IPipelineObserver<OnAddCharacterA>,
        IPipelineObserver<OnAddCharacter>
    {
        public void Execute(OnAddCharacterA pipelineEvent)
        {
            var state = pipelineEvent.Pipeline.State;
            var value = state.Get<string>("value");

            value = string.Format("{0}-A", value);

            state.Replace("value", value);
        }

        public void Execute(OnAddCharacter pipelineEvent)
        {
            var state = pipelineEvent.Pipeline.State;
            var value = state.Get<string>("value");

            value = string.Format("{0}-{1}", value, pipelineEvent.Character);

            state.Replace("value", value);
        }
    }

Next we will define the pipeline itself:

var pipeline = new Pipeline();

pipeline.RegisterStage("process")
	.WithEvent<OnAddCharacterA>()
	.WithEvent(new OnAddCharacter('Z'));

pipeline.RegisterObserver(new CharacterPipelineObserver());

pipeline.State.Add("value", "start");
pipeline.Execute();

Console.WriteLine(pipeline.State.Get<string>("value")); // outputs start-A-Z

We can now execute this pipeline with predictable results.

Pipelines afford us the ability to better decouple functionality. This means that we could re-use the same observer in multiple pipelines enabling us to compose functionality at a more granular level.

Product Versions
.NET net5.0 net5.0-windows net6.0 net6.0-android net6.0-ios net6.0-maccatalyst net6.0-macos net6.0-tvos net6.0-windows
.NET Core netcoreapp2.0 netcoreapp2.1 netcoreapp2.2 netcoreapp3.0 netcoreapp3.1
.NET Standard netstandard2.0 netstandard2.1
.NET Framework net461 net462 net463 net47 net471 net472 net48
MonoAndroid monoandroid
MonoMac monomac
MonoTouch monotouch
Tizen tizen40 tizen60
Xamarin.iOS xamarinios
Xamarin.Mac xamarinmac
Xamarin.TVOS xamarintvos
Xamarin.WatchOS xamarinwatchos
Compatible target framework(s)
Additional computed target framework(s)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (4)

Showing the top 4 NuGet packages that depend on Shuttle.Core.Pipelines:

Package Downloads
Shuttle.Esb The ID prefix of this package has been reserved for one of the owners of this package by NuGet.org.

Contains the core Shuttle.Esb assembly that should always be referenced when building Shuttle.Esb solutions.

Shuttle.Core.PipelineTransaction The ID prefix of this package has been reserved for one of the owners of this package by NuGet.org.

Provides a pipeline observer to handle transaction scopes.

Shuttle.Recall The ID prefix of this package has been reserved for one of the owners of this package by NuGet.org.

Event sourcing mechanism.

Shuttle.Core.Mediator.OpenTelemetry The ID prefix of this package has been reserved for one of the owners of this package by NuGet.org.

OpenTelemetry instrumentation for Shuttle.Core.Mediator implementations.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last updated
12.0.0 6,130 9/4/2022
11.0.1 274 4/9/2022
11.0.0 8,089 3/21/2022
10.1.0 5,246 2/9/2021
10.0.7 9,319 11/27/2020
10.0.6 49,203 7/4/2018
10.0.5 822 4/12/2018
10.0.4 1,562 4/8/2018
10.0.3 762 4/7/2018
10.0.2 6,030 2/13/2018