This quickstart gives you an example implementation of an aggregate root.
Clone the source code from Github before you get started.
Scenario
The scenario for this quickstart is e-commerce process, where you can place a booking through an API, and the aggregate root will decide if it is a valid purchase order or not.
What you need to get started
- The .NET 6 SDK should be installed
- The sample was created using Visual Studio 2022 community edition
- A general purpose azure storage account is used to store events.
- To use the outbox an azure service bus namespace or eventhub is required.
- The MessageHandler.EventSourcing.AzureTableStorage package is available from nuget.org
- The optional MessageHandler.EventSourcing.Outbox package is also available from nuget.org
Running the sample
Prior to being able to run the sample, you need to configure the user secrets file.
In the secrets file you must specify the following configuration values.
{
"azurestoragedata": "your azure storage connection string goes here",
"servicebusnamespace": "your azure service bus connection string goes here"
}
Also ensure a topic named orderbooking.events is created up front in the service bus namespace.
Once configured you can start the API project or run the unittests.
Designed with testing in mind
MessageHandler is intented to be test friendly.
This sample contains plenty of ideas on how to test an aggregate root without requiring a dependency on an actual storage account or servicebus namespace, and thus keep the tests fast.
- Unit tests: To test the actual logic in the aggregate root. Unit tests should make up the bulk of all tests in the system.
- Component tests: To test the api used to expose the aggregate root.
- Contract tests: To verify that the test doubles used in the unit and component tests are behaving the same as an actual dependency would. Note: contract verification files are often shared between producers and consumers of the contract.
How to implement it yourself
Check out the how to guide to learn how to implement this pattern or get started with the learning path, where you'll build an Aggregate Root yourself in lesson 3.