MassTransit.RabbitMq.Extensions.Hosting

KO | EN

gitlite — search

#python #react #ai #golang #go #machine-learning #rust #deep-learning #macos #windows #awesome #cli #mcp #open-source

MassTransit.RabbitMq.Extensions.Hosting

(★ 11)

Better configuration for RabbitMQ backed MassTransit with IHostedService

MassTransit.RabbitMq.Extensions.Hosting Latest Version Download

Download Latest Version (.zip)

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

[![CircleCI](https://circleci.com/gh/axle-h/MassTransit.RabbitMq.Extensions.Hosting/tree/master.svg?&style=shield)](https://circleci.com/gh/axle-h/MassTransit.RabbitMq.Extensions.Hosting/tree/master)
[![NuGet](https://img.shields.io/nuget/v/MassTransit.RabbitMq.Extensions.Hosting.svg)](https://www.nuget.org/packages/MassTransit.RabbitMq.Extensions.Hosting/)

# MassTransit.RabbitMq.Extensions.Hosting

MassTransit configuration extensions for `Microsoft.Extensions.DependencyInjection` using `Microsoft.Extensions.Hosting.IHostedService` and RabbitMQ.

Some conventions assumed in this package:

* Queue naming via application name.
* Exchange routing via remote microservice name.
* Simplified concept of commands by whether they expect a response or are fire-and-forget.
* Standard fault queues for catching/auditing failed fire-and-forget commands.
* Standard error queues for auditing/debugging hard failed request-response commands.

Some features over just consuming the MassTransit NuGet package directly:

* Provides a standard configuration mechanism based on `Microsoft.Extensions.DependencyInjection`. There is official support for this but it is very poor - it literally only supports consumer injection and no way of assigning consumers to distinct receive endpoints.
* Provides an `Microsoft.Extensions.Hosting.IHostedService` that manages the massTransit bus lifetime as part of ASP.Net Core or the new hosted service provider.
* Supports starting the application without RabbitMQ being present: the first time the bus is used, the request thread will block until RabbitMQ is available.
* Setup via connection string with amqp scheme.
* Endpoint configuration at DI setup time: means we're not passing around connection strings everywhere.

## Installation

The package is available on NuGet.

```bash
dotnet add package MassTransit.RabbitMq.Extensions.Hosting
```

## Usage

To use in `Startup.cs` in ASP.Net Core or `IHostBuilder.ConfigureServices` in a hosted service application:

```C#
public IServiceProvider ConfigureServices(IServiceCollection services)
{
    // You need a RabbitMQ connection string with a amqp scheme for this to work.
    var massTransitOptions = _configuration.GetMassTransitOptionsConnectionString();

// The application name will be prefixed to all consumer queues.
    // It must be shared with clients wishing to send a command.
    services.AddMassTransitRabbitMqHostedService("some_application_name", massTransitOptions)
            
            // Consuming by convention (a queue named some_application_name_some_command) with a single immediate retry.
            .ConsumeByConvention<CommandConsumer, ISomeCommand>(r => r.Immediate(1))
            
            // Setting up an endpoint by convention that supports the request-response pattern.
            // The convention based endpoint will send commands to some_remote_application_some_other_command.
            // The remote application should have a consumer setup with this interface by convention.
            .WithRequestResponseSendEndpointByConvention<ISomeOtherCommand, IResponse>("some_remote_application")
            
            // Setting up an endpoint by convention that supports the fire-and-forget pattern.
            // The convention is identical to the request-response endpoint above.
            .WithSendEndpointByConvention<ISomeDifferentCommand>("some_remote_application");
}
```

Registered consumers should inherit `IConsumer<TMessage>` for example:

```C#
public class CommandConsumer : IConsumer<ICommand>
{
    public async Task Consume(ConsumeContext<ICommand> context)
    {
        // Do some stuff

// ...
        var _someResult = ...

// Respond to client, preserving correlation ID.
        await context.RespondAsync<IResponse>(new {Result = _someResult, context.Message.CorrelationId });
    }
}
```

Clients should inject `IConfiguredSendEndpointProvider` and call `GetRequestClient<TRequest, TResponse>()` for request-response or `GetSendEndpoint<ICommand>()` for fire-and-forget e.g..

```C#
public class SomeClient
{
    private readonly IConfiguredSendEndpointProvider _configuredSendEndpointProvider;

public SomeClient(IConfiguredSendEndpointProvider configuredSendEndpointProvider)
    {
        _configuredSendEndpointProvider = configuredSendEndpointProvider;
    }

public async Task<IResponse> SendSomeCommand(ISomeCommand command, CancellationToken cancellationToken = default)
    {
        var requestClient = _configuredSendEndpointProvider.GetRequestClient<ISomeCommand, IResponse>();
        return await requestClient.Request(command, cancellationToken);
    }
}
```

## Example

See `example/Example.Client` for an example client (of a specific command), server (of that specific command) and auditing microservices.

Run `Run-Example.ps1` to see it working at scale in docker-compose. Whilst the example is running you can browse to `localhost:15672` to see the RabbitMQ management console i.e. to see the message flow in real-time.

Process:

1. Client sends a command to server command queue.
2. Server consumes the command:
3. Server will randomly fail to consume a command. When this happens:
   * The command is retried exactly once. If it succeeds this time then the normal success procedure is followed.
   * The retry fails so the server responds with an exception to the client.
   * MassTransit moves failed messages to a special `_error` queue: the audit service consumes these messages and logs them.
4. When the command is successfully consumed.
   * Server responds to client with a success message.
   * Server publishes an event for the command it processed.
   * Audit system and client log the event.

MassTransit.RabbitMq.Extensions.Hosting

MassTransit.RabbitMq.Extensions.Hosting Latest Version Download

Today's picks

Was this content helpful?

Recent Feedback

MassTransit.RabbitMq.Extensions.Hosting

MassTransit.RabbitMq.Extensions.Hosting Latest Version Download

Today's picks

Was this content helpful?

Recent Feedback

Download README