/// <summary>
/// Calls OnCompleted on all Subscribers, unsubscribes them,
/// and stops receiving messages on the queue.
/// </summary>
/// <exception cref="System.InvalidOperationException"></exception>
/// <returns>A result containing any Exceptions from removing Subscribers</returns>
public StopReceivingResult StopReceiving()
{
if (_observers.IsNone || _workers.IsNone || _tokenSource.IsNone)
{
throw new InvalidOperationException($"{nameof(BrokerClient)} has not started receiving");
}
var tokenSource = _tokenSource | CancellationTokenSource.CreateLinkedTokenSource(CancellationToken.None);
var workers = _workers | new ConcurrentBag <Task>();
var observers = _observers | new ConcurrentBag <IBrokerObserver>();
return(new StopReceivingResult(Try(() => tokenSource.Cancel()).Try())
.Append(Try(() => Task.WaitAll(workers.ToArray(), tokenSource.Token)).Try())
.Append(Try(() => _logger.Debug(message: "Receiver stopped")).Try())
.Append(Try(() => tokenSource.Dispose()).Try())
.Append(
_logger.Debug(observers, "Calling Observers OnCompleted").Aggregate(
new StopReceivingResult(),
(prev, next) =>
prev.Append(Try(() => next.OnCompleted()).Try())))
.Append(
new StopReceivingResult(Try(() =>
{
IBrokerObserver removing;
while (observers.TryTake(out removing))
{
}
;
_logger.Debug("All Observers Removed");
}).Try())));
}
/// <summary>
/// Adds error handling to IObserver.OnError
/// </summary>
/// <param name="self"></param>
/// <param name="exception"></param>
/// <param name="message"></param>
/// <param name="logger"></param>
/// <returns></returns>
public static Unit SendError(this IBrokerObserver self, Exception exception, Maybe <BrokerMessage> message, Maybe <Log> logger) =>
Try(() => self.OnError(exception, message))
.Match(_ => _,
e => logger.Error <Unit>(
new AggregateException(
exception,
logger.Debug(e, $"{nameof(self.OnNext)} failed. Calling {nameof(self.OnError)}")).GetExceptionChainMessagesWithSql()));
/// <summary>
/// Adds a new observer to receive future queue messages
/// </summary>
/// <remarks>Be aware that <see cref="IObserver{T}.OnNext(T)"/>, <see cref="IObserver{T}.OnError(Exception)"/>,
/// and <see cref="IObserver{T}.OnCompleted()"/> are called asynchronously;
/// so appropriate state sharing precautions should be taken to avoid race conditions.</remarks>
/// <param name="observer">New addition that needs to implement <see cref="IBrokerObserver"/></param>
/// <exception cref="System.ArgumentNullException"></exception>
/// <exception cref="System.InvalidOperationException">When <paramref name="observer"/> is not an <see cref="IBrokerObserver"/></exception>
/// <returns>A subscription that can be unsubscribed from by calling Dispose</returns>
public IDisposable Subscribe(IBrokerObserver observer)
{
if (!_observers.Contains(observer.AssertValue()))
{
_observers.Add(observer);
_logger.Debug($"Added {observer}");
}
return(new Subscription(_observers, observer, _logger));
}
protected virtual void Dispose(bool disposing)
{
if (!disposedValue)
{
if (disposing && _observer != null && _observers != null && _observers.Contains(_observer))
{
IBrokerObserver removing;
if (_observers.TryTake(out removing))
{
_logger.Debug($"Removed Observer: {ToString()}");
}
else
{
_logger.Error($"Failed to remove Observer: {ToString()}");
}
}
disposedValue = true;
}
}
/// <summary>
/// Adds error handling to IObserver.OnNext
/// </summary>
/// <param name="self"></param>
/// <param name="next"></param>
/// <param name="logger"></param>
/// <returns></returns>
public static Unit SendNext(this IBrokerObserver self, BrokerMessage next, Maybe <Log> logger) =>
Try(() => self.OnNext(next)).Match(
_ => _,
e => self.SendError(logger.Debug(e, $"{nameof(self.OnNext)} failed. Calling {nameof(self.OnError)}"), next, logger));
