Architect Tip: Application Architecture Diagrams Architect Tips

Welcome to architect tips. I am Jeffrey Palermo. And I am going to show you today how to use architecture diagrams in a really, really easy way. Now as we go through, there is a lot of resources, a lot of, interesting topics on the Azure DevOps podcast. You will want to make sure to check out that as a resource to you and on this show architect tips, I will answer your architect questions. All you have to do is tweet me @jeffreypalermo and I'll pick a question and, if I can put it into a short five-minute bite-sized chunk, I'm just going to make one of these out of it. Otherwise, I will just send you an email and I will answer it for you.
So, go ahead and send me a question there. And so now let us get into architect, architecture, diagrams, and I want to, I want to make it easy and show you some, diagrams that I use. So, let us take a system you want to communicate. You want to communicate what you want to either be built or what you are going to build with your teammates then you need to draw something.
If it cannot be drawn, it cannot be built. Every profession that creates something has some type of design diagram. And so, we need that here.  So, let us pretend that we are starting a work order application. We are going to build a work order application. And so, we need some diagrams that are going to communicate it, and bread and butter diagrams is going to be your diagram.
You could also think of it as a class diagram also. We are going to make ample use of sequence diagrams. Okay. Then you might have some patterns. In the case of a work order, a work order has a status, and it has a workflow. And so, we need to make use of a state machine diagram. And a lot of times, an activity diagram will be interesting or an overall dependency diagram.
So let's just take these and let's go through one at a time and see how quickly we can use these particular diagrams to describe a work order application in a fashion where you would actually understand what .NET code needs to flow from this. So, let us start with a dependency diagram, you know, I am a fan of onion architecture. If I am laying out a visual studio solution, and I say, you know what, it is going to be.net. It is going to be Blazor web assembly. We are going to use a C-sharp nine and we are going to use SQL server, we are going to pull it up, Azure. Well, one of the first things is what is my visual studio solution look like?
So, I am just going to quickly spec it out. I am not going to explain why, but I am going to have it core library. That is a, you know, dot net standard two. I am not going to go on all the rest of it. Then we are going to have a UI project. We are going to have a data access project, and I do not, I am not going to worry about my handwriting.
I am just going to do this. And then we're going to have, let's see what else, you know, I know that I need some unit tests, so we're going to have a unit test library and I'm going to have some integration tests. These are going to be projects. And so, you know to have him here and unit tests are going to be linked to core integration tests, going to be linked to data, access, and core most of the time.
And, if I put in acceptance tests, over here, most of the time they are linked to data, access core, and UI. So that is our test coverage. Now I did not put any arrows here. We need to communicate that. Well, the core needs to have no other dependencies. Then just .NET standard and whatever, most stable libraries. You are only as stable as your most stable library.
So, I am going to make sure that the UI references core, I am going to make sure that data access references, core unit just references core, ah, all incoming references. I like that. No outgoing references for core acceptance tests that let me just finish these. And I finished all of them. Alright. So that is our dependency diagram.
Now, what about our core? Object model or domain model. I love domain-driven, design the pattern, the la