Embeddable server

[Kinrany]

NATS server can be embedded in Go as a library.

Have you considered providing NATS as a library for other languages too? I'm particularly interested in Rust. A library is operationally much easier to start using in an existing server application.

[gcolliso]

@Jarema could you comment as our main Rust client maintainer? Thanks!

[aricart]

The NATS server is written in Go, thus if you call the correct functions, the server runs within your process. However, the other clients are just clients, there's no "server" role in the client.

[Kinrany]

I understand! Go code could in theory be exposed as a library to other languages via FFI, correct?

[niklasfp]

@Kinrany I'm actually kinda doing that for dotnet, I have a small go package that uses the nats server package and exposes some simple methods, that in turn is compiled to a.so and.dll utilizing go's cgo capabilities (go builmode=c-shared) and packed in a multiplatform dotnet nuget package.
So the ffi here is is just few exported functions from the libs and used from c# in my case, I guess the same could be done for rust.

This let's me have nats-server in-process wrapped in a Nats Server class to hide away the ffi part :)
NOTE: For now I've just exposed enough to:

1. create a server with config (accepting same args as nats-server) and add a custom logger to nats in go that forwards logs via a callback
2. Start the server
3. Stop the server

This is an extract from the generated c header

extern uintptr_t CreateServer(char* arguments, loggerFunc loggerFuncPtr);
extern GoInt StartServer(uintptr_t handle);
extern GoInt ShutdownServer(uintptr_t handle);
extern void FreeServer(uintptr_t handle);

For now I use the nats client for all management etc so still going over a socket, but loopback

This is an example on how I use the wrapper in a console test app in c#

var services = new ServiceCollection()
    .AddLogging(c =>
        c.AddConsole())
    .AddSingleton<NatsServer.Net.NatsServer>()
    .AddSingleton(new NatsServerOptions()
        {
            Arguments = new[]
            {
                "-js",
            }
        })
        .BuildServiceProvider();

var server = services.GetRequiredService<NatsServer.Net.NatsServer>();

var cts = new CancellationTokenSource();
server.Start(cts.Token);

[Denrask]

Hi @niklasfp !

I'm looking to use nats-server embedded in .NET as well. As your post is over 1 year old, I'd like to know if you have more information or an example repository somewhere? :) Thanks!

[meraydin]

+1