108 lines
4.0 KiB
Markdown
108 lines
4.0 KiB
Markdown
---
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title: Inter-process communication with gRPC and Unix domain sockets
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author: jamesnk
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description: Learn how to use gRPC for inter-process communication with Unix domain sockets.
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monikerRange: '>= aspnetcore-5.0'
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ms.author: wpickett
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ms.date: 01/18/2023
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uid: grpc/interprocess-uds
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---
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# Inter-process communication with gRPC and Unix domain sockets
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[!INCLUDE[](~/includes/not-latest-version.md)]
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By [James Newton-King](https://twitter.com/jamesnk)
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.NET supports inter-process communication (IPC) using gRPC. For more information about getting started with using gRPC to communicate between processes, see [Inter-process communication with gRPC](xref:grpc/interprocess).
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[Unix domain sockets (UDS)](https://wikipedia.org/wiki/Unix_domain_socket) is a widely supported IPC transport that's more efficient than TCP when the client and server are on the same machine. This article discusses how to configure gRPC communication over UDS.
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## Prerequisites
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* .NET 5 or later
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* Linux, macOS, or [Windows 10/Windows Server 2019 or later](https://devblogs.microsoft.com/commandline/af_unix-comes-to-windows/)
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## Server configuration
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Unix domain sockets are supported by [Kestrel](xref:fundamentals/servers/kestrel), which is configured in `Program.cs`:
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```csharp
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var socketPath = Path.Combine(Path.GetTempPath(), "socket.tmp");
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var builder = WebApplication.CreateBuilder(args);
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builder.WebHost.ConfigureKestrel(serverOptions =>
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{
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serverOptions.ListenUnixSocket(socketPath, listenOptions =>
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{
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listenOptions.Protocols = HttpProtocols.Http2;
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});
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});
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```
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The preceding example:
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* Configures Kestrel's endpoints in <xref:Microsoft.AspNetCore.Hosting.WebHostBuilderKestrelExtensions.ConfigureKestrel%2A>.
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* Calls <xref:Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerOptions.ListenUnixSocket%2A> to listen to a UDS with the specified path.
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* Creates a UDS endpoint that isn't configured to use HTTPS. For information about enabling HTTPS, see [Kestrel HTTPS endpoint configuration](xref:fundamentals/servers/kestrel/endpoints#listenoptionsusehttps).
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## Client configuration
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`GrpcChannel` supports making gRPC calls over custom transports. When a channel is created, it can be configured with a <xref:System.Net.Http.SocketsHttpHandler> that has a custom <xref:System.Net.Http.SocketsHttpHandler.ConnectCallback>. The callback allows the client to make connections over custom transports and then send HTTP requests over that transport.
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> [!NOTE]
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> Some connectivity features of `GrpcChannel`, such as client side load balancing and channel status, can't be used together with Unix domain sockets.
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Unix domain sockets connection factory example:
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```csharp
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public class UnixDomainSocketsConnectionFactory
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{
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private readonly EndPoint endPoint;
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public UnixDomainSocketsConnectionFactory(EndPoint endPoint)
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{
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this.endPoint = endPoint;
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}
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public async ValueTask<Stream> ConnectAsync(SocketsHttpConnectionContext _,
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CancellationToken cancellationToken = default)
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{
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var socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
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try
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{
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await socket.ConnectAsync(this.endPoint, cancellationToken).ConfigureAwait(false);
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return new NetworkStream(socket, true);
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}
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catch
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{
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socket.Dispose();
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throw;
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}
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}
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}
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```
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Using the custom connection factory to create a channel:
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```csharp
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public static readonly string SocketPath = Path.Combine(Path.GetTempPath(), "socket.tmp");
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public static GrpcChannel CreateChannel()
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{
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var udsEndPoint = new UnixDomainSocketEndPoint(SocketPath);
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var connectionFactory = new UnixDomainSocketsConnectionFactory(udsEndPoint);
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var socketsHttpHandler = new SocketsHttpHandler
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{
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ConnectCallback = connectionFactory.ConnectAsync
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};
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return GrpcChannel.ForAddress("http://localhost", new GrpcChannelOptions
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{
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HttpHandler = socketsHttpHandler
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});
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}
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```
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Channels created using the preceding code send gRPC calls over Unix domain sockets.
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