We can use Microsoft.Extensions.Hosting pacakge to host a .net core console application by using the HostBuilder API to start building gRPC host and setting it up.
In order to run the gRPC service, we first need to start/stop Grpc.Core.Server in a hosted service. A hosted service is basically a piece of code that is run by the host when the host itself is started and the same for when it is stopped. The following code implement a GrpcHostedService to override IHostedService interface:
using System.Threading;
using System.Threading.Tasks;
using Grpc.Core;
using Microsoft.Extensions.Hosting;
namespace Grpc.Host
{
public class GrpcHostedService: IHostedService
{
private Server _server;
public GrpcHostedService(Server server)
{
_server = server;
}
public Task StartAsync(CancellationToken cancellationToken)
{
_server.Start();
return Task.CompletedTask;
}
public async Task StopAsync(CancellationToken cancellationToken) => await _server.ShutdownAsync();
}
}
In the Program.cs, use HostBuilder API to start building our grpc host and setting it up:
public class Program
{
public static async Task Main(string[] args)
{
var hostBuilder = new HostBuilder()
// Add configuration, logging, ...
.ConfigureServices((hostContext, services) =>
{
// Better to use Dependency Injection for GreeterImpl
Server server = new Server
{
Services = {Greeter.BindService(new GreeterImpl())},
Ports = {new ServerPort("localhost", 5000, ServerCredentials.Insecure)}
};
services.AddSingleton<Server>(server);
services.AddSingleton<IHostedService, GrpcHostedService>();
});
await hostBuilder.RunConsoleAsync();
}
}
By doing this, the generic host will automatically run StartAsync on our hosted service, which in turn will call StartAsync on the Server instance, essentially start the gRPC server.
When we shut down the host with Control-C, the generic host will automatically call StopAsync on our hosted service, which again will call StopAsync on the Server instance which will do some clean up.
For other configuration in HostBuilder, you can see this blog.
