PostgreSQL

• PostgreSQL intro
• Showcase posgres image and pgAdmin

  • Add to docker-compose.yml: ```yml services:

    discountdb: image: postgres

    pgadmin: image: dpage/pgadmin4

  volumes: postgres_data: pgadmin_data:

      
    - Add to `docker-compose.override.yml`:
    ```yml
    services:
  
      discountdb:
      container_name: discountdb
      environment:
        - POSTGRES_USER=admin
        - POSTGRES_PASSWORD=admin1234
        - POSTGRES_DB=DiscountDb
      restart: always
      ports:
        - "5432:5432"
      volumes:
        # NOTE: in materials this is set to diff dir
        #       and wont work with newer psql versions
        - postgres_data:/var/lib/postgresql/
  
      pgadmin:
        container_name: pgadmin
        environment:
          - PGADMIN_DEFAULT_EMAIL=razvoj.softvera.matf@gmail.com
          - PGADMIN_DEFAULT_PASSWORD=admin1234
        restart: always
        ports:
          - "5050:80"
        volumes:
          - pgadmin_data:/root/.pgadmin
  

• Run the new containers

  $ docker-compose up discountdb pgadmin
  

• Navigate to localhost:5050
• Add New Server
  • General
    • Name: DiscountServer
  • Connection (creds from discount db)
    • Host name/address: discountdb
    • Port: 5432
    • Maintenance database: postgres
    • Username: admin
    • Password: admin1234
  • Save
• Open DiscountDb
• Tools > Query tool

  CREATE TABLE Coupon (
    ID SERIAL PRIMARY KEY NOT NULL,
    ProductName VARCHAR(24) NOT NULL,
    Description TEXT,
    Amount INT
  );
  

• sql INSERT INTO Coupon (ProductName, Description, Amount) VALUES ('IPhone X', 'IPhone Discount', 150); INSERT INTO Coupon (ProductName, Description, Amount) VALUES ('Huawei Plus', 'Huawei Discount', 110); INSERT INTO Coupon (ProductName, Description, Amount) VALUES ('Xiaomi Mi 9', 'Xiaomi Discount', 75); INSERT INTO Coupon (ProductName, Description, Amount) VALUES ('Samsung 10', 'Samsung Discount', 100); :
• Open coupon table
  • Right click > Refresh
  • Right click > View/Edit Data > All rows
  • Verify data is added

Discount.Common init

• Open Rider and load Webstore solution
• Add new solution folder Services/Discount
• Create new project
  • On the left side, select Class Library instead of Web
  • name: Discount.Common
  • path: Webstore/Services/Discount
  • Framework: .NET 10
• Install:
  • Npgsql
  • Dapper
  • AutoMapper NOTE: deprecated AutoMapper.Extensions.Microsoft.DependencyInjection
  • Microsoft.Extensions.Configuration
  • Microsoft.Extensions.Configuration.Binder
  • Microsoft.Extensions.DependencyInjection.Abstractions

Discount.Common coding:

• Coding:
  • Entities
    • Coupon.cs
  • Data
    • ICouponContext.cs
    • CouponContext.cs
  • DTOs
    • BaseCouponDTO.cs
    • BaseIdentityCouponDTO.cs
    • CouponDTO.cs
    • CreateCouponDTO.cs
    • UpdateCouponDTO.cs
  • Repositories
    • ICouponRepository.cs
    • CouponRepository.cs
  • Extensions
    • DiscountCommonExtensions.cs

Discount.API init

• Create new WebAPI project
  • name: Discount.API
  • path: Webstore/Services/Discount
  • Framework: .NET 10
  • Template: Web.API
  • (opt) Do not use top-level statements
  • Auth: no auth
  • Advanced: no https
• Reference Discount.Common
  • Add > Reference > Discount.Common
• Install:
  • Swashbuckle.AspNetCore
  • Swashbuckle.AspNetCore.Swagger
  • Swashbuckle.AspNetCore.SwaggerGen
  • Swashbuckle.AspNetCore.SwaggerUI

Discount.API coding

• Coding:
  • Controllers/
    • CouponController.cs
  • appSettings.Development.json
  • Program.cs
• Testing:
  • Start discountdb via docker-compose
  • Run Discount.API via Rider
  • Open Swagger, search for Samsung 10 product name
• Add Dockerfile to Discount.API
• Add to docker-compose.yml

  services:
    discount.api:
      image: discount.api
      build:
        context: .
        dockerfile: Services/Discount/Discount.API/Dockerfile
  

• Add to docker-compose.override.yml:

  services:
    discount.api:
      container_name: discount.api
      environment:
        - ASPNETCORE_ENVIRONMENT=Development
        - "DatabaseSettings:ConnectionString=Server=discountdb;Port=5432;Database=DiscountDb;User Id=admin;Password=admin1234;"
      depends_on:
        - discountdb
      ports:
        - "8002:8080"
  

Discount.GRPC init

• Create new gRPC Service project
  • name: Discount.GRPC
  • path: Webstore/Services/Discount
  • Framework: .NET 10
  • Template: gRPC Service
  • (opt) Do not use top-level statements
• Reference Discount.Common
  • Add > Reference > Discount.Common
• Install:
  • Google.Protobuf
  • Grpc.Core
  • Grpc.Tools
• Go through the default template
  • greet.proto
  • GreeterService
• Run the default template

  $ curl --http2-prior-knowledge http://localhost:<PORT>
  Communication with gRPC endpoints must be made through a gRPC client...
  

• Use BloomRPC to test
  • Server address: localhost:
  • Import greet.proto file on the left side
  • Open SayHello
  • Send request:

    {
    "name": "Ivan"
    }
    

Discount.GRPC coding

• Delete template files
  • greet.proto
  • GreeterService
• Coding:
  • Protos/
    • coupon.proto
    • Properties > Build action > Protobuf
  • Services/
    • CouponService.cs (just blank file)
• Map CouponService in Program.cs instead of the default GreeterService
• Rebuild, Rider should generate base CouponProtoService.CouponProtoServiceBase
  • If it isn’t there, try reloading the project
• Explore interface
• Coding:
  • Services
    • CouponService.cs
  • Add db conn string to launchSettings.json (copy it from Discount.API)
  • Program.cs ```cs — | builder.Services.AddGrpc();

    • builder.Services.AddDiscountCommonServices();

    • builder.Services.AddAutoMapper(configuration =>

    • {

    • configuration.CreateMap<CouponDTO, GetDiscountResponse>().ReverseMap();

    • configuration.CreateMap<CouponDTO, GetRandomDiscountsResponse.Types.Coupon>().ReverseMap();

    • | });

• Replace proto file in BloomRPC
• Attempt request for Samsung 10, should work
• Add to docker-compose.yml

  services:
    discount.grpc:
      image: discount.grpc
      build:
        context: .
        dockerfile: Services/Discount/Discount.GRPC/Dockerfile
  

• Add to docker-compose.override.yml:

  services:
    discount.grpc:
      container_name: discount.grpc
      environment:
        - ASPNETCORE_ENVIRONMENT=Development
        - "DatabaseSettings:ConnectionString=Server=discountdb;Port=5432;Database=DiscountDb;User Id=admin;Password=admin1234;"
      depends_on:
        - discountdb
      ports:
        - "8003:8080"
  

Extending Basket with gRPC

• Install:
  • Grpc.AspNetCore
  • (opt) Google.Protobuf
  • (opt) Grpc.Tools
• Add to Basket.API.csproj:

    <ItemGroup>
        <Protobuf Include="..\..\Discount\Discount.GRPC\Protos\coupon.proto" GrpcServices="Client">
            <Link>Protos\coupon.proto</Link>
        </Protobuf>
    </ItemGroup>
  

  (should also work with Right click > Add existing file …)

• Coding:
  • GrpcServices/
    • CouponGrpcService.cs
  • Controllers/
    • BasketController.cs ```cs | private readonly IBasketRepository _repository;

    • private readonly CouponGrpcService _couponGrpcService;

    • | private readonly ILogger _logger; ```

    + |  ... BasketController(..., CouponGrpcService couponGrpcService, ILogger<BasketController> logger)
      |  {
      |      _repository = repository ?? throw ...
    + |      _couponGrpcService = couponGrpcService ?? throw ...
    + |      _logger = logger ?? throw ...
      |  }
    

      | ... UpdateBasket([FromBody] ShoppingCart basket)
      | {
    + |     foreach (var item in basket.Items)
    + |     {
    + |         try
    + |         {
    + |             var coupon = await _couponGrpcService.GetDiscount(item.ProductName);
    + |             item.Price -= coupon.Amount;
    + |         }
    + |         catch (RpcException e)
    + |         {
    + |             _logger.LogInformation("Error while retrieving coupon for item {ProductName}: {message}", item.ProductName, e.Message);
    + |         }
    + |     }
    
    + |     return Ok(await _repository.UpdateBasket(basket));
    + | }
    

  • Program.cs

    builder.Services.AddGrpcClient<CouponProtoService.CouponProtoServiceClient>(
    options => options.Address = new Uri(builder.Configuration["GrpcSettings:DiscountUrl"]));
    builder.Services.AddScoped<CouponGrpcService>();
    

  • appsettings.Development.json: ```json

  • “GrpcSettings”: {

  • “DiscountUrl”: “http://localhost:5003”

  • | }, ```
  • docker-compose.override.yml ```yml | basket.api: | … | environment: | …

  • - “GrpcSettings:DiscountUrl=http://discount.grpc:8080”

    depends_on:

    …

  • | - discount.grpc ```
• docker-compose down
• docker-compose build

• docker-compose up -d

• Testing:
  • Open Discount.API
    • GET: IPhone X
    • Should return coupon with 150
  • Open Basket API
  • GET: username rs2
  • PUT:

    {
    "username": "rs2",
    "items": [
      {
        "quantity": 2,
        "color": "white",
        "price": 950,
        "productId": "602d2149e773f2a3990b47f5",
        "productName": "IPhone X"
      },
      {
        "quantity": 1,
        "color": "white",
        "price": 380,
        "productId": "602d2149e773f2a3990b47f9",
        "productName": "HTC U11+ Plus"
      }
    ]
    }
    

    Should return response where the price is 800 for IPhone X

Unit testing

• Create new solution folder: Webstore/Tests/Basket/
• Create test project:
  • Type: Unit Test
  • Location: Webstore/Tests/Basket/
  • Name: Basket.API.Tests
  • Type: NUnit
• Coding:
  • Basket.API:
    • Introduce: Services/BasketService.cs
    • Refactor BasketController
      • Move controller method implementations to BasketService.cs
      • Introduce ICouponGrpcService.cs and make CouponGrpcService implement it
      • Add Extensions/BasketExtensions.cs
  • Basket.API.Tests:
    • Delete default template classes
    • Coding:
      • Mocks/
        • TestBasketRepository.cs
        • TestCouponGrpcService.cs
        • TestLogger.cs
      • BasketServiceTests.cs