ScadaBridge/src/ScadaLink.CLI/ClusterConnection.cs

using System.Collections.Immutable;
using Akka.Actor;
using Akka.Cluster.Tools.Client;
using Akka.Configuration;
using ScadaLink.Commons.Messages.Management;

namespace ScadaLink.CLI;

public class ClusterConnection : IAsyncDisposable
{
    private ActorSystem? _system;
    private IActorRef? _clusterClient;

    public async Task ConnectAsync(IReadOnlyList<string> contactPoints, TimeSpan timeout)
    {
        var seedNodes = string.Join(",", contactPoints.Select(cp => $"\"{cp}\""));
        var config = ConfigurationFactory.ParseString($@"
            akka {{
                actor.provider = remote
                remote.dot-netty.tcp {{
                    hostname = ""127.0.0.1""
                    port = 0
                }}
            }}
        ");

        _system = ActorSystem.Create("scadalink-cli", config);

        var initialContacts = contactPoints
            .Select(cp => $"{cp}/system/receptionist")
            .Select(path => ActorPath.Parse(path))
            .ToImmutableHashSet();

        var clientSettings = ClusterClientSettings.Create(_system)
            .WithInitialContacts(initialContacts);

        _clusterClient = _system.ActorOf(ClusterClient.Props(clientSettings), "cluster-client");

        // Wait for connection by sending a ping
        // ClusterClient doesn't have a direct "connected" signal, so we rely on the first Ask succeeding
        await Task.CompletedTask;
    }

    public async Task<object> AskManagementAsync(ManagementEnvelope envelope, TimeSpan timeout)
    {
        if (_clusterClient == null) throw new InvalidOperationException("Not connected");

        var response = await _clusterClient.Ask(
            new ClusterClient.Send("/user/management", envelope),
            timeout);

        return response;
    }

    public async ValueTask DisposeAsync()
    {
        if (_system != null)
        {
            await CoordinatedShutdown.Get(_system).Run(CoordinatedShutdown.ClrExitReason.Instance);
            _system = null;
        }
    }
}