private Task StartMessageReceiverInternal(string queueName, MessageReceiverOptions options,
Func <ISQSMessage, Task> asyncMessageProcessor, CancellationToken cancellationToken)
{
if (options.MaxNumberOfMessagesPerPoll > 10 || options.MaxNumberOfMessagesPerPoll < 1)
{
throw new ArgumentException($"nameof(options.MaxNumberOfMessagesPerPoll) must be between 1 and 10",
nameof(options.MaxNumberOfMessagesPerPoll));
}
if (options.MessagePollWaitTimeSeconds < 0 || options.MessagePollWaitTimeSeconds > 20)
{
throw new ArgumentException($"{nameof(options.MessagePollWaitTimeSeconds)} must be within the range 0 to 20.",
nameof(options.MessagePollWaitTimeSeconds));
}
if (options.VisibilityTimeoutSeconds.HasValue && options.VisibilityTimeoutSeconds.Value < 0)
{
throw new ArgumentException($"{nameof(options.VisibilityTimeoutSeconds)} must be 0 or greater, or null.",
nameof(options.MessagePollWaitTimeSeconds));
}
return(Task.Run(async() =>
{
while (!cancellationToken.IsCancellationRequested)
{
var messageAttributesQuery = new List <string> {
"All"
};
var receiveMessageResponse = await ReceiveMessageAsync(queueName,
waitTimeSeconds: options.MessagePollWaitTimeSeconds,
maxNumberOfMessages: options.MaxNumberOfMessagesPerPoll,
visibilityTimeoutSeconds: options.VisibilityTimeoutSeconds,
messageAttributeNames: messageAttributesQuery);
foreach (var message in receiveMessageResponse.Messages)
{
var sqsMessage = new SQSMessage(this, queueName, message.ReceiptHandle)
{
Body = message.Body
};
if (message.MessageAttributes.Count > 0)
{
var messageAttributes = new Dictionary <string, string>();
foreach (var messageAttribute in message.MessageAttributes)
{
if (messageAttribute.Value.StringValue != null)
{
messageAttributes.Add(messageAttribute.Key, messageAttribute.Value.StringValue);
}
}
sqsMessage.MessageAttributes = messageAttributes;
}
await asyncMessageProcessor(sqsMessage);
}
}
}, cancellationToken));
}
private Task StartMessageReceiverInternal(string queueName, MessageReceiverOptions options,
Func <string, Task <bool> > asyncMessageProcessor, CancellationToken cancellationToken)
{
if (options.MaxNumberOfMessagesPerPoll > 10 || options.MaxNumberOfMessagesPerPoll < 1)
{
throw new ArgumentException($"nameof(options.MaxNumberOfMessagesPerPoll) must be between 1 and 10",
nameof(options.MaxNumberOfMessagesPerPoll));
}
if (options.MessagePollWaitTimeSeconds < 0 || options.MessagePollWaitTimeSeconds > 20)
{
throw new ArgumentException($"{nameof(options.MessagePollWaitTimeSeconds)} must be within the range 0 to 20.",
nameof(options.MessagePollWaitTimeSeconds));
}
if (options.VisibilityTimeoutSeconds.HasValue && options.VisibilityTimeoutSeconds.Value < 0)
{
throw new ArgumentException($"{nameof(options.VisibilityTimeoutSeconds)} must be 0 or greater, or null.",
nameof(options.MessagePollWaitTimeSeconds));
}
if (options.WaitForQueue)
{
WaitForQueue(queueName, options, cancellationToken);
}
return(Task.Run(async() =>
{
while (!cancellationToken.IsCancellationRequested)
{
var receiveMessageResponse = await ReceiveMessageAsync(queueName,
waitTimeSeconds: options.MessagePollWaitTimeSeconds,
maxNumberOfMessages: options.MaxNumberOfMessagesPerPoll,
visibilityTimeoutSeconds: options.VisibilityTimeoutSeconds);
foreach (var message in receiveMessageResponse.Messages)
{
var success = await asyncMessageProcessor(message.Body);
if (success)
{
await DeleteMessageAsync(queueName, message.ReceiptHandle);
}
}
}
}, cancellationToken));
}
/// <summary>
/// Synchronously waits for a queue to be available.
/// </summary>
private void WaitForQueue(string queueName, MessageReceiverOptions options, CancellationToken cancellationToken)
{
for (var i = 0; i < options.WaitForQueueTimeoutSeconds; i++)
{
try
{
GetQueueUrlAsync(queueName).GetAwaiter().GetResult();
return;
}
catch (QueueDoesNotExistException)
{
Task.Delay(1000, cancellationToken).Wait(cancellationToken);
}
}
throw new QueueDoesNotExistException($"Queue {queueName} does still not exist after waiting for {options.WaitForQueueTimeoutSeconds} seconds.");
}
/// <summary>
/// Starts a long running process that checks the queue for any new messages, and handles the messages on the queue in the processor specified.
/// </summary>
/// <param name="queueName">The name of the queue</param>
/// <param name="options">Options for the receiver behaviour.</param>
/// <param name="asyncMessageProcessor">The message processor which will handle the message picked from the queue</param>
/// <param name="cancellationToken">The receiver process will check the status of this token and cancel the long running process if cancellation is requested.</param>
/// <returns></returns>
public Task StartMessageReceiver(string queueName, MessageReceiverOptions options, Func <string, Task <bool> > asyncMessageProcessor, CancellationToken cancellationToken)
{
return(StartMessageReceiverInternal(queueName, options, asyncMessageProcessor, cancellationToken));
}
/// <summary>
/// Starts a long running process that checks the queue for any new messages, and handles the messages on the queue in the processor specified.
///
/// Message should be explicitly acked to be removed from queue.
/// </summary>
/// <param name="queueName">The name of the queue</param>
/// <param name="options">Options for the receiver behaviour.</param>
/// <param name="messageProcessor">The message processor which will handle the message picked from the queue</param>
/// <param name="cancellationToken">The receiver process will check the status of this token and cancel the long running process if cancellation is requested.</param>
/// <returns></returns>
public Task StartMessageReceiver(string queueName, MessageReceiverOptions options,
Action <ISQSMessage> messageProcessor, CancellationToken cancellationToken)
{
return(StartMessageReceiverInternal(queueName, options, async(arg) => messageProcessor(arg), cancellationToken));
}
