add basic GRPC communication

netsd/Handlers/Init.cs

@@ -1,3 +1,10 @@
+using Grpc.Core;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Server.Kestrel.Core;
+using Microsoft.Extensions.DependencyInjection;
+using StartGrpc;
+
 namespace netsd.Handlers;
 
 public class Init
@@ -8,11 +15,29 @@ public class Init
 	{
 		_socketBuilder.WebHost.ConfigureKestrel(options =>
 		{
-			options.ListenUnixSocket("/tmp/netsd.sock");
+			options.ListenUnixSocket("/tmp/netsd.sock", listenOptions =>
+			{
+				listenOptions.Protocols = HttpProtocols.Http2;
+			});
 		});
 
+		_socketBuilder.Services.AddGrpc();
+
 		var app = _socketBuilder.Build();
 
+		app.MapGrpcService<StartGrpc>();
+
 		app.Run();
 	}
 }
+
+public class StartGrpc : StartRpc.StartRpcBase
+{
+	public override Task<StartReply> StartService(StartRequest request, ServerCallContext context)
+	{
+		return Task.FromResult(new StartReply
+		{
+			Success = true,
+		});
+	}
+}

netsd/Handlers/Start.cs

@@ -0,0 +1,17 @@
+using netsd.Utils;
+using StartGrpc;
+
+namespace netsd.Handlers;
+
+public class Start
+{
+	public Start()
+	{
+		using var channel = UDSConnector.CreateChannel();
+
+		var client = new StartRpc.StartRpcClient(channel);
+		var reply = client.StartService(new StartRequest{ Name = "Awoo" });
+
+		Console.WriteLine(reply.Success);
+	}
+}

netsd/Program.cs

@@ -2,13 +2,17 @@ using System.CommandLine;
 using netsd.Handlers;
 
 var initCommand = new Command("init", "Run and bring up all default services");
+var startCommand = new Command("start", "Starts up a netsd service");
 
 var rootCommand = new RootCommand("Linux service manager written in C#");
 rootCommand.AddCommand(initCommand);
+rootCommand.AddCommand(startCommand);
 
 initCommand.SetHandler((() =>
 {
 	new Init();
 }));
 
+startCommand.SetHandler((() => new Start()));
+
 return await rootCommand.InvokeAsync(args);

netsd/Protos/Start.proto

@@ -0,0 +1,17 @@
+syntax = "proto3";
+
+option csharp_namespace = "StartGrpc";
+
+package netsd;
+
+service StartRpc {
+	rpc StartService (StartRequest) returns (StartReply);
+}
+
+message StartRequest {
+	string name = 1;
+}
+
+message StartReply {
+	bool Success = 1;
+}

netsd/Utils/UDSConnector.cs

@@ -0,0 +1,47 @@
+using System.Net;
+using System.Net.Sockets;
+using Grpc.Net.Client;
+
+namespace netsd.Utils;
+
+public class UDSConnector
+{
+	private readonly EndPoint _endPoint;
+	private static readonly string _socketPath = Path.Combine(Path.GetTempPath(), "netsd.sock");
+
+	private UDSConnector(EndPoint endPoint)
+	{
+		_endPoint = endPoint;
+	}
+
+	private async ValueTask<Stream> _connectAsync(SocketsHttpConnectionContext _, CancellationToken cancellationToken = default)
+	{
+		var socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
+
+		try
+		{
+			await socket.ConnectAsync(_endPoint, cancellationToken).ConfigureAwait(false);
+			return new NetworkStream(socket, true);
+		}
+		catch
+		{
+			socket.Dispose();
+			throw;
+		}
+	}
+	
+	public static GrpcChannel CreateChannel()
+	{
+		var udsEndPoint = new UnixDomainSocketEndPoint(_socketPath);
+		var connectionFactory = new UDSConnector(udsEndPoint);
+		var socketsHttpHandler = new SocketsHttpHandler
+		{
+			ConnectCallback = connectionFactory._connectAsync
+		};
+
+		return GrpcChannel.ForAddress("http://localhost", new GrpcChannelOptions
+		{
+			HttpHandler = socketsHttpHandler
+		});
+	}
+}

netsd/netsd.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
+<Project Sdk="Microsoft.NET.Sdk">
 
 	<PropertyGroup>
 		<OutputType>Exe</OutputType>
@@ -28,10 +28,18 @@
 	</PropertyGroup>
 	
 	<ItemGroup>
-		<PackageReference Include="Microsoft.Extensions.Hosting" Version="7.0.0" />
+		<FrameworkReference Include="Microsoft.AspNetCore.App" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<PackageReference Include="Grpc.AspNetCore" Version="2.50.0-pre1" />
 		<PackageReference Include="runtime.linux-musl-x64.Microsoft.DotNet.ILCompiler" Version="7.0.0" />
 		<PackageReference Include="runtime.linux-x64.Microsoft.DotNet.ILCompiler" Version="7.0.0" />
 		<PackageReference Include="System.CommandLine" Version="2.0.0-beta4.22272.1" />
 	</ItemGroup>
 
+	<ItemGroup>
+		<Protobuf Include="Protos\Start.proto" />
+	</ItemGroup>
+
 </Project>