natsdotnet/tests/NATS.Server.Tests/LeafNodes/LeafAccountScopedDeliveryTests.cs

using Microsoft.Extensions.Logging.Abstractions;
using NATS.Client.Core;
using NATS.Server.Auth;
using NATS.Server.Configuration;

namespace NATS.Server.Tests.LeafNodes;

public class LeafAccountScopedDeliveryTests
{
    [Fact]
    public async Task Remote_message_delivery_uses_target_account_sublist_not_global_sublist()
    {
        const string subject = "orders.created";
        await using var fixture = await LeafAccountDeliveryFixture.StartAsync();

        await using var remoteAccountA = await fixture.ConnectAsync(fixture.Spoke, "a_sub");
        await using var remoteAccountB = await fixture.ConnectAsync(fixture.Spoke, "b_sub");
        await using var publisher = await fixture.ConnectAsync(fixture.Hub, "a_pub");

        await using var subA = await remoteAccountA.SubscribeCoreAsync<string>(subject);
        await using var subB = await remoteAccountB.SubscribeCoreAsync<string>(subject);
        await remoteAccountA.PingAsync();
        await remoteAccountB.PingAsync();
        await fixture.WaitForRemoteInterestOnHubAsync("A", subject);

        await publisher.PublishAsync(subject, "from-leaf-a");

        using var receiveTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
        var msgA = await subA.Msgs.ReadAsync(receiveTimeout.Token);
        msgA.Data.ShouldBe("from-leaf-a");

        using var leakTimeout = new CancellationTokenSource(TimeSpan.FromMilliseconds(500));
        await Should.ThrowAsync<OperationCanceledException>(async () =>
            await subB.Msgs.ReadAsync(leakTimeout.Token));
    }
}

internal sealed class LeafAccountDeliveryFixture : IAsyncDisposable
{
    private readonly CancellationTokenSource _hubCts;
    private readonly CancellationTokenSource _spokeCts;

    private LeafAccountDeliveryFixture(NatsServer hub, NatsServer spoke, CancellationTokenSource hubCts, CancellationTokenSource spokeCts)
    {
        Hub = hub;
        Spoke = spoke;
        _hubCts = hubCts;
        _spokeCts = spokeCts;
    }

    public NatsServer Hub { get; }
    public NatsServer Spoke { get; }

    public static async Task<LeafAccountDeliveryFixture> StartAsync()
    {
        var users = new User[]
        {
            new() { Username = "a_pub", Password = "pass", Account = "A" },
            new() { Username = "a_sub", Password = "pass", Account = "A" },
            new() { Username = "b_sub", Password = "pass", Account = "B" },
        };

        var hubOptions = new NatsOptions
        {
            Host = "127.0.0.1",
            Port = 0,
            Users = users,
            LeafNode = new LeafNodeOptions
            {
                Host = "127.0.0.1",
                Port = 0,
            },
        };

        var hub = new NatsServer(hubOptions, NullLoggerFactory.Instance);
        var hubCts = new CancellationTokenSource();
        _ = hub.StartAsync(hubCts.Token);
        await hub.WaitForReadyAsync();

        var spokeOptions = new NatsOptions
        {
            Host = "127.0.0.1",
            Port = 0,
            Users = users,
            LeafNode = new LeafNodeOptions
            {
                Host = "127.0.0.1",
                Port = 0,
                Remotes = [hub.LeafListen!],
            },
        };

        var spoke = new NatsServer(spokeOptions, NullLoggerFactory.Instance);
        var spokeCts = new CancellationTokenSource();
        _ = spoke.StartAsync(spokeCts.Token);
        await spoke.WaitForReadyAsync();

        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
        while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);

        return new LeafAccountDeliveryFixture(hub, spoke, hubCts, spokeCts);
    }

    public async Task<NatsConnection> ConnectAsync(NatsServer server, string username)
    {
        var connection = new NatsConnection(new NatsOpts
        {
            Url = $"nats://{username}:pass@127.0.0.1:{server.Port}",
        });
        await connection.ConnectAsync();
        return connection;
    }

    public async Task WaitForRemoteInterestOnHubAsync(string account, string subject)
    {
        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
        while (!timeout.IsCancellationRequested)
        {
            if (Hub.HasRemoteInterest(account, subject))
                return;

            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
        }

        throw new TimeoutException($"Timed out waiting for remote interest {account}:{subject}.");
    }

    public async ValueTask DisposeAsync()
    {
        await _hubCts.CancelAsync();
        await _spokeCts.CancelAsync();
        Hub.Dispose();
        Spoke.Dispose();
        _hubCts.Dispose();
        _spokeCts.Dispose();
    }
}