Holon

This repository provides an in-development messaging and service layer ontop of RabbitMQ.

Goals

Holon was created to satisfy a mix-match of goals that are not completely fullfiled by competing libraries. Some are too heavy, others have dependency bloat or inconsistent API’s. This library attempts to provide the following tenants:

• Decoupled transport architecture and few dependencies
• No use of language specific technologies
• Support various types of services
• Decoupling remote-procedure call from the service layer
• Event system built-in

Getting Started

You can install the package using either the CLI:

dotnet add package Holon

or from the NuGet package manager:

Install-Package Holon

Example

The repository comes with an example project, but a practical example of how this library can be used is documented below.

Factory Service

The factory service provides a way to look at the total production and command a factory to start and stop. The implementation here is a console application but it can be embedded anywhere that is async friendly.

[RpcContract]
interface IFactoryController 
{
    [RpcOperation]
    Task<double> GetProductionToday();
    [RpcOperation]
    Task StartProduction();
    [RpcOperation]
    Task StopProduction();
}
class FruitFactory : IFactoryController 
{
    public async Task GetProductionToday() {
        return 10000.0;
    }
    public async Task StartProduction() {
        // start our factory up!
    }
    public async Task StopProduction() {
        // shut it down before any fruit gets bruised
    }
}
class ServiceHost {
    static void Main() => MainAsync().Wait();
    static async Task MainAsync() {
        // attach node
        Node node = await Node.CreateAsync("amqp://localhost");
        // attach our service
        await node.AttachAsync("factory:fruit", ServiceType.Singleton, RpcBehaviour.Bind<IFactoryController>(new FruitFactory()));
        // wait forever
        await Task.Delay(Timeout.InfiniteSpan);
    }
}

Client

The client can also be embedded anywhere that is async friendly, and provides a simple way to obtain a proxy and begin communicating with the fruit factory. The interface class is carried over from the previous example.

class Client {
    static void Main() => MainAsync().Wait();
    static async Task MainAsync() {
        // attach node
        Node node = await Node.CreateAsync("amqp://localhost");
        // get a proxy to the factory
        IFactoryController controller = node.Proxy<IFactoryController>("factory:fruit");
        // start production!
        await controller.StartProduction();
    }
}

Licenses

Contributing

Any pull requests or bug reports are welcome, please try and keep to the existing style conventions and comment any additions.