Runic.Platform.Runtime 0.8.0-preview.3

Runic.Platform.Runtime

Shared scoped lifetime, file leases, atomic writes and native provider infrastructure.

Preview API targeting .NET 10. Native providers are explicitly selected; this package has no Desktop or ASP.NET Core dependency.

Single instance and replies to later launches

ApplicationInstance.ClaimAsync makes the first launch of an application the running instance and forwards later launches to it over a Unix domain socket in a directory only the user can use (on Linux, macOS and Windows). By default a later launch hands over its arguments and exits, and the running instance raises IApplicationInstance.Launched.

With ApplicationInstanceOptions.ReplyToLaunches, a later launch, such as a command line, also waits for the running instance's reply: messages (output lines or JSON events, as UTF-8 strings of at most 1 MiB) and an exit status. Set it in every process of the application, so whichever process is the running instance answers.

var options = new ApplicationInstanceOptions { ReplyToLaunches = true };
var claim = await ApplicationInstance.ClaimAsync("org.example.Manager", ApplicationLaunch.FromProcess(args), options);

// A later launch: print the running instance's messages and exit with its status.
if (claim is PlatformResult<ApplicationInstanceClaim>.Success { Value: ApplicationInstanceClaim.Forwarded { Reply: { } reply } })
{
    await using (reply)
    {
        // Ctrl+C asks the running instance to cancel; its last messages and exit status still arrive.
        Console.CancelKeyPress += (_, e) => { e.Cancel = true; _ = reply.CancelAsync(); };
        await foreach (var line in reply.ReadMessagesAsync()) Console.WriteLine(line);
        return await reply.WaitForExitAsync() is PlatformResult<int>.Success(var code) ? code : 1;
    }
}

// The running instance: launches that wait carry a reply; complete each one.
instance.Launched += (_, launch) => _ = Task.Run(async () =>
{
    if (launch.Reply is not { } reply) { /* Only handed over: raise the window. */ return; }
    await reply.WriteAsync("working");
    await reply.CompleteAsync(reply.Cancelled.IsCancellationRequested ? 130 : 0);
});

• IApplicationLaunchReply.Cancelled is cancelled when the launching process asks to cancel, disconnects (disposing its reply, or cancelling a read), or when the running instance ends. Writes after the launching process went away return false.
• A write waits while the launching process does not read, so large output is not buffered in memory. Pass a token to WriteAsync to bound the wait; a write cancelled that way ends the reply.
• When the running instance ends or crashes before the exit status, the messages end and WaitForExitAsync reports Failed(IoError).
• An instance claimed without ReplyToLaunches, or by an SDK before 0.8.0-preview.3, refuses launches that wait: the claim fails with ResourceBusy and an ApplicationInstance diagnostic, and the launch is not handled. Launches without ReplyToLaunches keep the one-way protocol and reach any instance.