Hello again, I think we couldn't understand each other :) I know that i can create razor pages. My question is out of scope of what kind of user interface tech. you use.
just let me try another way to explain myself.
Let's think about 3 different bounded contexts.
1- Sales 2- Marketing 3- Shipping
All of them has product properties related to product.
So let's say.
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
}
public class ProductPrice
{
public int ProductId { get; set; }
public decimal Price { get; set; }
}
public class ProductShippingOptions
{
public int Id { get; set; }
public int ProductId { get; set; }
public List<ShippingOption> Options { get; set; } = new List<ShippingOption>();
}
public class ShippingOption
{
public int Id { get; set; }
public int ProductShippingOptionsId { get; set; }
public string Option { get; set; }
public int EstimatedMinDeliveryDays { get; set; }
public int EstimatedMaxDeliveryDays { get; set; }
}
so each bounded context is responsible for product details that they care.
So let's think about a moment I am listing products on my web app (it doesn't matter which tech i use). The user wants to see name price and shipping options of the product on a listed view.
If my web app is Monolith App, How should i compose those 3 different services together in a list? If my web app is Microservice, How should i compose those 3 different services together in a list?
3 bounded contexts are different modules and they don't know about each other.
As i see on EshopOnAbp, most of the data is copied between bounded contexts.
here is the code from EshopOnAbp.
This is the OrderItem from Ordering Bounded Context.
public class OrderItem : Entity<Guid>
{
public string ProductCode { get; private set; }
public string ProductName { get; private set; }
public string PictureUrl { get; private set; }
public decimal UnitPrice { get; private set; }
public decimal Discount { get; private set; }
public int Units { get; private set; }
public Guid ProductId { get; private set; }
here is the product from Catalog Bounded Context
public class Product : AuditedAggregateRoot<Guid>
{
/// <summary>
/// A unique value for this product.
/// ProductManager ensures the uniqueness of it.
/// It can not be changed after creation of the product.
/// </summary>
[NotNull]
public string Code { get; private set; }
[NotNull]
public string Name { get; private set; }
public float Price { get; private set; }
public int StockCount { get; private set; }
public string ImageName { get; private set; }
And in Basket Bounded Context. the app calls the Catalog Bounded Context to get the Product info and caching it.(through _productPublicGrpcClient). This is some kind of composition in microservice level but isn't this should be composed in the gateway instead of Basket Service?
public class BasketItemDto
{
public Guid ProductId { get; set; }
public string ProductName { get; set; }
public string ProductCode { get; set; }
public string ImageName { get; set; }
public int Count { get; set; }
public float TotalPrice { get; set; }
}
is there any other way like viewmodel composition and decomposition that I can use so we don't need to copy the staff around for microservices and i am curious how this composition can happen if i decided to use my modules as monolith?
Of course, the UI layer should be one web app, actually PublicWebApp is it, It just references the UI class library of other modules.
as i understand all the microservice modules do not have any presentation layer which means EshopOnAbp.PublicWeb project do not depend on any microservice module presentation layer (cause there is none, which is not needed on microservice modules in this case). It implements the necessary user interface inside that project. For ex:
public class ProductDetailModel : AbpPageModel
{
[BindProperty(SupportsGet = true)]
public int OrderNo { get; set; }
public ProductDto Product { get; private set; }
public bool IsPurschased { get; private set; }
private readonly IPublicProductAppService _productAppService;
private readonly IOrderAppService _orderAppService;
public ProductDetailModel(
IPublicProductAppService productAppService,
IOrderAppService orderAppService)
{
_productAppService = productAppService;
_orderAppService = orderAppService;
}
public async Task OnGet(Guid id)
{
IsPurschased = (await _orderAppService.GetMyOrdersAsync(new GetMyOrdersInput())).Any(p => p.Items.Any(p => p.ProductId == id));
Product = await _productAppService.GetAsync(id);
}
}
this is a sample from EshopOnAbp, it is ProductDetail page as you can see it is dependent on OrderAppService and ProductAppService while creating the ui. You can do this if you implement the presentation layer out of your modules, like in the demo project EshopOnAbp.
I will try to ask the question from another perspective. If I need to convert the EshopOnAbp project to monolith app, in where should i create the user interface for ProductDetail page?
Cause product belongs to Catalog Module and Order belongs to ordering module. Or you shouldn't implement the ProductDetail page in any modules presentation layer and keep it in your main app?
Hello @liangshiwei As i understand (pls correct me if i am wrong), In microservice solution you don't use the user interface(or web layer) for microservices instead one web app that will unify whole views. And this web app(in EshopOnAbp,it is PublicWebApp) do the requests through gateway (WebPublicGateWay) by using reverse proxy.
So here is the question my project will stay monolith for a while and according to changes it might evolve to microservices in the future, while my modules are monolith where should i implement the user interface to create an order, and if this is going to be inside the module, what should i do to list the products?
Thank you for your patience and for your help a lot.
Hello again thank you for the answer.
What makes you think you have to be coupled to identity service for identity user? I would suggest digging more on Domain Driven Design to see how to handle these kind of coupling (using data duplication etc).
Actually i was talking about it from the administration microservice perspective, I was looking at the problem like "reduce the number of intersynched communications if it possible". So that was my intuition at the first place but i understand your point.
There is a great free-ebook Domain Driven Design with the ABP Framework i would suggest. And also Domain-Driven Design: Tackling Complexity in the Heart of Software by Eric Evans.
Thanks for the suggestions i have already read the Domain Driven Design book from Abp, i will check the Eric Evans's Book also.
Thanks for the assistance.
Hello again, I really understand now, also i read this doc from microsoft, which is not a good practice to do synced communications between microservices as they say https://docs.microsoft.com/en-us/dotnet/architecture/microservices/architect-microservice-container-applications/communication-in-microservice-architecture
https://docs.microsoft.com/en-us/dotnet/architecture/microservices/architect-microservice-container-applications/media/communication-in-microservice-architecture/sync-vs-async-patterns-across-microservices.png
So this brings me another question Isn't there anyway to get users without being coupled to identity service. For ex first thing that comes to my mind is to make identityservice not being a seperate microservice and include it in administration service? But probably it is the most used service? Why did you choose to make it a seperate service if it is gonna be coupled to administration service? or how do i need to do decisions when i am seperating monolith project to microservices? Is there any guide or docs or any book to read to learn more about it?
I really appreciate your help, and thank you for answering my questions.
Allright i think it is more clear in my mind now, thank you for the answer.
So to summarize, you removed internal gateway because there was only one synched (http) communication which is between administration service and identity service.
All the permissions are defined in application contracts, so this brings us to the conclusion, whatever microservice that implements permission manager module needs to define every microservice application contracts module, so permission manager can do crud operations on the permissions?
And as the last thing if i want to create a communication for ex between productservice and saas service
"AuthServer": { "Authority": "https://localhost:44322", "RequireHttpsMetadata": "true" }, "RemoteServices": { "AbpIdentity": { "BaseUrl": "https://localhost:44388/", "UseCurrentAccessToken": "false" } }, "IdentityClients": { "Default": { "GrantType": "client_credentials", "ClientId": "Adzup_AdministrationService", "ClientSecret": "1q2w3e*", "Authority": "https://localhost:44322", "Scope": "IdentityService" } },
Further Questions:
So as i understand identityclients options are configured in AbpHttpClientIdentityModelWebModule but in the docs it has been used AbpHttpClientIdentityModelModule can you clarify the difference between 2?
Also if i am planning lots of communications between different microservices internally isn't the internal gateway with ocelot is better approach maybe it is not very efficient if one microservice needs to call another but overall can we say that if we have many communcations between our microservices isn't it better to configure an internal gateway instead of configuring all the microservices one by one? What i am asking is are you planning to replace back internal gateway with another solution than ocelot or is it gonna be gone for good?
Thank you so much for the help and assistance
