Pluralsight DDD Fundamentals Sample

Sample code for the Pluralsight DDD Fundamentals course (2nd edition) by Julie Lerman and Steve "ardalis" Smith. If you are looking for the .NET Framework sample from the original 2014 DDD Fundamentals course, it's available as the ddd-vet-clinic sample.

Additional exercises from Steve's DDD workshops (separate from Pluralsight course)

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Table of Contents

1. Running the Sample

  1.1 Docker

  1.2 Visual Studio and VS Code

2. Student Recommendations

3. Architecture Notes

4. Developer Notes

5. Credits

1. Running the Sample

You can run this sample in Docker or in Visual Studio. Docker is recommended.

Watch how to set up and run the sample app using Docker, Visual Studio, or VS Code here:

Running the DDD Fundamentals Sample by Philippe Vaillancourt

1.1 Docker

The easiest way to run the sample is using docker. Download the source and run this command from the root folder:

docker-compose build --parallel
docker-compose up

The build step will take a while. It's way faster if you run it in parallel, assuming you have a fast machine and download speed. The up command is much faster but will also take a moment and you may see some errors as apps try to connect to docker or databases before they're responsive. Give it a minute or two and it should succeed. RabbitMQ errors should go away once that service starts up. If you get SQL Server login errors, I've found it's best to just restart everything (ctrl-c, then docker-compose up again).

This will start RabbitMQ (for messaging between apps) and build and run each of the applications involved in the sample:

• FrontDesk.Api
• FrontDesk.Blazor
• ClinicManagement.Api
• ClinicManagement.Blazor
• VetClinicPublic

It also adds the following supporting containers:

• RabbitMQ with Management
• FrontDesk SQL Server
• ClinicManagement SQL Server
• Test Mailserver (Papercut)

Once running, you should be able to access the various apps using localhost (HTTP not HTTPS because of Kestrel configuration restrictions) and the following ports (you can also find these bindings in the docker-compose.yml file):

The ports in () are only open inside of docker, not exposed otherwise.

Here are the (localhost) links you should use once the apps are running in docker:

• FrontDesk
• Clinic Management
• VetClinicPublic (there are links here to send test emails and view them, too)

If you want to quickly clean up all of your docker containers (All of them not just the ones you created for this sample!) you can run this command:

docker kill $(docker ps -q)

Note that any data changes you make will not be persisted if you docker remove the SQL Server container. The Docker container for SQL Server will be recreated and seeded on the next docker run. In other scenarios, you might be using Docker volumes to persist or share the database across container instances but that's overkill for this demo.

1.2 Visual Studio and VS Code

You may need to configure a local NuGet server and put this package in it:

/FrontDesk/src/FrontDesk.Blazor/deps/Pluralsight.DDD.Deps/Pluralsight.DDD.Deps.1.0.0.nupkg

Running the sample from Visual Studio (or VS Code or Rider, etc) requires some additional setup. You will need to run multiple solutions side by side. You will also need to run RabbitMQ and PaperCut, ideally as a docker images. You can run RabbitMQ from Docker using this command:

docker run --rm -it --hostname ddd-sample-rabbit -p 15672:15672 -p 5672:5672 rabbitmq:3-management

You should be able to open localhost:15672 to view RabbitMQ management interface (login as guest/guest).

When new appointments are created, confirmation emails are sent out to clients. Start a test mailserver using this command (learn more):

docker run --name=papercut -p 25:25 -p 37408:37408 jijiechen/papercut:latest

You should be able to open localhost:37408 to view Papercut test mailserver management interface, where sent emails will appear.

You can run individual solutions independently from one another, but obviously you won't see live sync between them when entities are updated, new appointments created, appointment confirmation emails clicked, etc. To get that, you'll need to run all three of the web applications:

• FrontDesk
• ClinicManagement
• VetClinicPublic

Some of the ports may not be set up in config; you may need to adjust them by hand. They assume you'll run primarily in docker to see everything running. If you're trying to get things working outside of docker, you should try with the ports shown in the table above.

2. Student Recommendations

If you're coming here from the Pluralsight Domain-Driven Design Fundamentals course, great! Download this sample and look around. See if you can run it on your machine (docker recommended). Your next assignment is to look at the TODO comments in the code, and see if you can implement any of them. You can view todo comments as tasks in Visual Studio, or there are plugins for VS Code.

Don't worry about submitting a pull request for any TODO comments you fix. They're left there intentionally to help students learn by providing some ways to extend the solution from the course.

3. Architecture Notes

The reference application is built as a small set of related monolithic ASP.NET Core applications. The two Blazor applications are built using a modified version of the CleanArchitecture solution template and also bears a great deal of similiarity to the eShopOnWeb application (also maintained by @ardalis). To learn more about migrating toward a domain-centric architecture from a data-centric one, check out Steve's two courses on N-Tier architecture on Pluralsight. You'll also find videos covering Clean Architecture on Steve's YouTube channel as well as on the eShopOnWeb home page.

If you or your team need help with architecting your .NET application following principles of clean architecture, with or without microservices, Steve and his team and NimblePros have a great deal of experience helping clients do just that. Get in touch.

4. Developer Notes

If you're new to this kind of application development, and you have a Pluralsight subscription, I strongly advise you to learn about SOLID principles and various code smells and refactoring techniques. You'll find the background in these principles informs most of the design decisions used in the individual classes and projects used in the sample code provided here. If you're really serious about learning these topics, watch the original versions of these courses, which were able to go into more depth (more recent courses need to be shorter since Pluralsight found too many students didn't complete longer courses. But not you - you have what it takes to finish the whole thing. Right?). They're available from Steve's author page on Pluralsight.

The sample doesn't include exhaustive test coverage, but does demonstrate some automated tests. If testing is new to you, Julie has a great course on automated testing that you should check out.

4.1 Referenced NuGet Packages

This course uses several NuGet packages that you may find useful.

Ardalis.ApiEndpoints A simple base class that lets you keep your API endpoints small and focused on one endpoint at a time. MVC is replaced with Request-EndPoint-Response (REPR).

Ardalis.GuardClauses Contains common guard clauses so you can use them consistently. Also can be easily extended to apply your own guards for custom/domain exception cases.

Ardalis.Specification An implementation of the Specification design pattern that is well-suited to work with ORMs like Entity Framework (Core).

Ardalis.Specification.EntityFrameworkCore Adds EF Core-specific functionality, including a default implementation of a generic EF repository that supports Specifications.

Ardalis.Result Provides a generic result type that can be returned from application services. Can easily be translated into HTTP status codes or ActionResult types.

Ardalis.HttpClientTestExtensions Removes boilerplate code from ASP.NET Core API integration/functional tests.

Blazored.LocalStorage Blazor utility for accessing browser local storage in Blazor WebAssembly apps.

MediatR Used to implement mediator pattern for commands and events.

Pluralsight.DDD.Deps Includes required trial binaries from Telerik. Currently this includes both Kendo UI and Blazor controls; Kendo should be replaced with just Blazor later in 2021. To build locally you may need to place this package in a local nuget repository. This package and its contents are subject to Telerik's EULA located in the same folder.

PluralsightDdd.SharedKernel An example SharedKernel package used by this sample built just for this course.

MassTransit.RabbitMQ Client for communicating with RabbitMQ.

5. Credits

This sample is from Julie Lerman and Steve Smith's Pluralsight course. The original sample was written for .NET Framework by Steve. The current .NET 5 version was initially ported with the help of Shady Nagy. Progress Software provided the Blazor Scheduler control used to display the clinic's schedule*.

* Initial version is using a Kendo schedule since certain features weren't available at recording time

Additional credits include:

Matheus Penido: Fixing a bug (https://github.com/ardalis/pluralsight-ddd-fundamentals/issues/36) https://github.com/matheuspenido https://www.linkedin.com/in/matheus-penido-8419a890/

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