On this post, let's explore MassTransit's scheduler messaging system using RabbitMQ
On a previous post, I demoed how to create a MassTransit client/server application using RabbitMQ, .NET Core and Linux. Today we will explore another very interesting functionality: the ability to schedule messages to send them in the future. My experiences with MassTransit so far have been fantastic, however, there are a few use cases that I still would like to test. On this post, we cover the scheduled message use case, testing the in-memory solution.
Persistence Requirements
In order to keep our data persisted for the scheduler to use we'll need to configure MassTransit's storage with one of the following services:- Quartz.Net in a hosted server
- Azure Service Bus
- RabbitMQ by installing a plugin
- a test-driven In-Memory implementation
On this post, we'll spike out the in-memory solution due to its simpler requirements but the behaviour should be equivalent for different transports.
Referencing Packages
MassTransit's Scheduling Api utilizes Quartz.Net. So, for it to work, we will need the to add a reference to the MassTransit.Quartz package to your project with:
$ dotnet add reference <project-name> MassTransit.Quartz --version 5.1.3
Once the reference is added, run dotnet restore to load the necessary extension methods to do the initialization. Initialization
The initialization code for the in-memory implementation as simple as adding a call to UseInMemoryScheduler() on your bus configuration.
Using the in-memory scheduler uses non-durable storage. If the process terminates, any scheduled messages will be lost, immediately, never to be found again. For any production system, using a standalone service is recommended with persistent storage.
Sample Code
The code below shows a simple implementation of MassTransit and its scheduling system:Running the Demo app
So, I run my app and my code schedules a message to be sent 3 seconds after sent by the user. This is my output:
Conclusion
Hope this serves as an introduction to the scheduling feature within MassTransit. I've been using MassTransit for a couple of years now and definitely
would recommend it as a framework for your distributed systems.
Want to learn more about MassTransit? Please consider reading the
following posts:
Source Code
The source for this post is located on my GitHub page.
In case you're interested, I recently pushed a more updated MassTransit/Docker/.NET Core 3.1 implementation to GitHub here: https://github.com/hd9/masstransit-rabbitmq
See Also
- My journey to 1 million articles read
- Adding Application Insights telemetry to your ASP.NET Core website
- Async Request/Response with MassTransit, RabbitMQ, Docker and .NET core
- Creating ASP.NET Core websites with Docker
- Send emails from ASP.NET Core websites using SendGrid and Azure
- Distributed caching in ASP.NET Core using Redis, MongoDB and Docker
- Hosting NuGet packages on GitHub
- Configuration in .NET Core console applications
- How to build and run ASP.NET Core apps on Linux
- How to create a Ubuntu Desktop on Azure
- Monitor ASP.NET applications using Application Insights and Azure Alerts