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public class RabbitMqTriggerListener : IListener | |
{ | |
private readonly ITriggeredFunctionExecutor _executor; | |
private readonly RabbitMqTriggerAttribute _attribute; | |
IModel _model { get; } | |
IBasicPublishBatch _createBasicPublishBatch => CreateBasicPublishBatch(); | |
private string _connectionString; | |
private string _hostName; | |
private string _queueName; | |
private string _userName; | |
private string _password; | |
private int _port; | |
private string _deadLetterExchangeName; | |
private string _consumerTag; | |
private bool _disposed; | |
private bool _started; | |
private EventingBasicConsumer _consumer; | |
private readonly ILogger _logger; | |
public RabbitMqTriggerListener(ITriggeredFunctionExecutor executor, RabbitMqTriggerAttribute attribute, ILogger logger) | |
{ | |
_executor = executor; | |
_attribute = attribute; | |
_logger = logger; | |
_queueName = _attribute.QueueName; | |
attribute.LoadRabbitSettings(); | |
ConnectionFactory connectionFactory = new ConnectionFactory(); | |
connectionFactory.Uri = GenerateRabbitHostUri(); | |
_model = connectionFactory.CreateConnection().CreateModel(); | |
} | |
public Task StartAsync(CancellationToken cancellationToken) | |
{ | |
ThrowIfDisposed(); | |
if (_started) | |
{ | |
throw new InvalidOperationException("The listener has already been started."); | |
} | |
_model.QueueDeclare(_attribute.QueueName, false, false, false); | |
_consumer = new EventingBasicConsumer(_model); | |
_consumer.Received += async (model, ea) => | |
{ | |
FunctionResult result = await _executor.TryExecuteAsync(new TriggeredFunctionData() { TriggerValue = ea }, cancellationToken); | |
if (result.Succeeded) | |
{ | |
_model.BasicAck(ea.DeliveryTag, false); | |
} | |
else | |
{ | |
if (ea.BasicProperties.Headers == null || !ea.BasicProperties.Headers.ContainsKey("requeueCount")) | |
{ | |
CreateHeadersAndRepublish(ea); | |
} | |
else | |
{ | |
RepublishMessages(ea); | |
} | |
} | |
}; | |
_consumerTag = _model.BasicConsume(queue: _queueName, autoAck: false, consumer: _consumer); | |
_started = true; | |
return Task.CompletedTask; | |
} | |
public Task StopAsync(CancellationToken cancellationToken) | |
{ | |
if (!_started) | |
{ | |
throw new InvalidOperationException("The listener has not yet been started or has already been stopped"); | |
} | |
_model.BasicCancel(_consumerTag); | |
_model.Close(); | |
_started = false; | |
_disposed = true; | |
return Task.CompletedTask; | |
} | |
public IBasicPublishBatch CreateBasicPublishBatch() | |
{ | |
return _model.CreateBasicPublishBatch(); | |
} | |
internal void CreateHeadersAndRepublish(BasicDeliverEventArgs ea) | |
{ | |
_model.BasicAck(ea.DeliveryTag, false); | |
if (ea.BasicProperties.Headers == null) | |
{ | |
ea.BasicProperties.Headers = new Dictionary<string, object>(); | |
} | |
ea.BasicProperties.Headers["requeueCount"] = 0; | |
//_logger.LogDebug("Republishing message"); | |
_model.BasicPublish(exchange: string.Empty, routingKey: ea.RoutingKey, basicProperties: ea.BasicProperties, body: ea.Body); | |
} | |
internal void RepublishMessages(BasicDeliverEventArgs ea) | |
{ | |
int requeueCount = Convert.ToInt32(ea.BasicProperties.Headers["requeueCount"]); | |
// Redelivered again | |
requeueCount++; | |
ea.BasicProperties.Headers["requeueCount"] = requeueCount; | |
if (Convert.ToInt32(ea.BasicProperties.Headers["requeueCount"]) < 5) | |
{ | |
_model.BasicAck(ea.DeliveryTag, false); // Manually ACK'ing, but resend | |
//_logger.LogDebug("Republishing message"); | |
_model.BasicPublish(exchange: string.Empty, routingKey: ea.RoutingKey, basicProperties: ea.BasicProperties, body: ea.Body); | |
} | |
else | |
{ | |
// Add message to dead letter exchange | |
//_logger.LogDebug("Requeue count exceeded: rejecting message"); | |
_model.BasicReject(ea.DeliveryTag, false); | |
} | |
} | |
internal Uri GenerateRabbitHostUri() | |
{ | |
return new Uri($"amqp://{_attribute.Username}:{_attribute.Password}@{_attribute.HostName}:{_attribute.Port}"); | |
} | |
public void Cancel() | |
{ | |
StopAsync(CancellationToken.None).Wait(); | |
} | |
public void Dispose() | |
{ | |
} | |
private void ThrowIfDisposed() | |
{ | |
if (_disposed) | |
{ | |
throw new ObjectDisposedException(null); | |
} | |
} | |
} |
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