gRPC .NET Core advanced example

This project was created to demonstrate advanced implementation of .NET Core gRPC services including unit tests and integration tests

It is created as a set of microsevices communicating via gRPC.

The entrypoint is Grpc.Dotnet.Todos.Api REST API with a single TodoController.

Overview

This project is using MediatR, AutoMapper, EntityFramework Core InMemory, custom MessageOrchestrator and custom IServiceClient wrapper.

It also shows how to create unit tests, integration test and mock gRPC clients.

There is also a custom configuration for gRPC ports that *.Server projects are starting on: in the appsettings.json, there is RpcServer:Port value, which is used inside the Program.cs by extensions method webBuilder.ConfigureGrpcServer()

MediatR

MediatR for bussiness logic and calling external gRPC services.

AutoMapper

AutoMapper for auto-mapping gRPC request/response classes to MediatR commands/queries and DTO results. It is also used for .ProjectTo() in EntityFramework Core InMemory

MessageOrchestrator

The MessageOrchestrator is used in the implementation of gRPC services, e.g. PermissionsServiceV1 and is responsible for mapping (AutoMapper) incomming gRPC request into MediatR query/command and invoking corresponding handler. This is a convenient way of automated calling MediatR handlers based on AutoMapper configuration.

IServiceClient<>

There is a custom implementation for gRPC clients which are wrapped in IServiceClient to easly add them to project and then mock them in unit tests or integration tests.

To add a gRPC client, e.g. XMyGrpcService to project:

1. add reference to XMyGrpcService.RpcApi project.
2. in the Startup.ConfigureServices() add services.AddRpcClients(this.Configuration).AddClient<XMyGrpcService.XMyGrpcServiceClient>()
3. in the appsettings.json add section:

"RpcClients": {
    "XMyGrpcServiceClient": {
      "Host": "127.0.0.1",
      "Port": "44444"
    }
  }

The XMyGrpcServiceClient configuration name must be the same as your generated gRPC client name class from XMyGrpcService.RpcApi project.

Workflow

1. HTTP request goes to Todos.Api
2. The request is mapped to MediatR query or command
3. The query or command is then processed by a MeditaR handler
4. The handler checks permissions by calling Grpc.Dotnet.Permissions.Server gRPC server.
5. The handler optionally send a request to gRPC server Grpc.Dotnet.Notifications.Server

Startup

Run multiple projects

1. From command line:

cd <this repo directory>

dotnet run --project .\src\Notifications\Grpc.Dotnet.Notifications.Server\Grpc.Dotnet.Notifications.Server.csproj

dotnet run --project .\src\Permissions\Grpc.Dotnet.Permissions.Server\Grpc.Dotnet.Permissions.Server.csproj

dotnet run --project .\src\Todos\Grpc.Dotnet.Todos.Api\Grpc.Dotnet.Todos.Api.csproj

dotnet run --project .\src\Todos\Grpc.Dotnet.Todos.Server\Grpc.Dotnet.Todos.Server.csproj

2. From Visual Studio:

Test HTTP api (Todos.Api)

1. Install recommended VSCode extension REST Client: humao.rest-client and open <this repo directory>\test-api.http to make some test requests.
2. Or use Postman and create requests to http://localhost:5000/api/todos/[...]

Test gRPC requests

Recommended and easy to use tool is BloomRPC