GrpcServiceSample

ASP.NET Core gRPC service example

This sample shows using Dapr with ASP.NET Core gRPC Service. This application is a simple and not-so-secure banking application. The application uses the Dapr state-store for its data storage.

It exposes the following endpoints over GRPC:

• /getaccount: Get the account information for the account specified by id
• /deposit: Accepts a Protobuf payload to deposit money to an account
• /withdraw: Accepts a Protobuf payload to withdraw money from an account

The application also registers for pub/sub with the deposit and withdraw topics.

Prerequisitess

• .NET 6+ installed
• Dapr CLI
• Initialized Dapr environment
• Dapr .NET SDK

Running the example

To run the sample locally run this command in this project root directory:

dapr run --app-id grpcsample --app-port 5050 --app-protocol grpc -- dotnet run

The application will listen on port 5050 for GRPC.

Client Examples

See InvokeGrpcBalanceServiceOperationAsync, InvokeGrpcDepositServiceOperationAsync and InvokeGrpcWithdrawServiceOperationAsync on DaprClient project.

Code Samples

All of the interesting code in this sample is in Startup.cs and Services/BankingService.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddGrpc();

    services.AddDaprClient();
}

AddDaprClient() registers the Dapr integration with grpc service. This also registers the DaprClient service with the dependency injection container. This service can be used to interact with the Dapr state-store.

---

app.UseEndpoints(endpoints =>
{
    endpoints.MapGrpcService<BankingService>();

    ...
});

MapGrpcService() exposes BankingService grpc service into ASP.NET Core route endpoints.

---

public class BankingService : AppCallback.AppCallbackBase
{
    ...
}

You need to inherit AppCallback.AppCallbackBase that will be called by the Dapr runtime to invoke method, register for pub/sub topics and register bindings.

---

public override async Task<InvokeResponse> OnInvoke(InvokeRequest request, ServerCallContext context)
{
    ...
}

You need to implement this overridable method to support Dapr's service invocation.

---

public override Task<ListTopicSubscriptionsResponse> ListTopicSubscriptions(Empty request, ServerCallContext context)
{
    ...
}

You need to implement this overridable method to support Dapr's pub/sub topic register.

---

public override async Task<TopicEventResponse> OnTopicEvent(TopicEventRequest request, ServerCallContext context)
{
    ...
}

You need to implement this overridable method to support Dapr's pub/sub topic handle.