public async Task <(string QueueName, string MessageId)> EnqueueAsync(BlobTriggerMessage message, CancellationToken cancellationToken)
{
string contents = JsonConvert.SerializeObject(message, JsonSerialization.Settings);
var receipt = await _queue.AddMessageAndCreateIfNotExistsAsync(BinaryData.FromString(contents), cancellationToken).ConfigureAwait(false);
_watcher.Notify(_queue.Name);
return(QueueName : _queue.Name, MessageId : receipt.MessageId);
}
private static QueueMessage CreateMessage(string functionId, string eTag)
{
BlobTriggerMessage triggerMessage = new BlobTriggerMessage
{
FunctionId = functionId,
// BlobType = StorageBlobType.BlockBlob, $$$
ContainerName = TestContainerName,
BlobName = TestBlobName,
ETag = eTag
};
return(CreateMessage(triggerMessage));
}
private static QueueMessage CreateMessage(BlobTriggerMessage triggerMessage)
{
return(CreateMessage(JsonConvert.SerializeObject(triggerMessage)));
}
public async Task <FunctionResult> ExecuteAsync(QueueMessage value, CancellationToken cancellationToken)
{
BlobTriggerMessage message = JsonConvert.DeserializeObject <BlobTriggerMessage>(value.Body.ToValidUTF8String(), JsonSerialization.Settings);
if (message == null)
{
throw new InvalidOperationException("Invalid blob trigger message.");
}
string functionId = message.FunctionId;
if (functionId == null)
{
throw new InvalidOperationException("Invalid function ID.");
}
// Ensure that the function ID is still valid. Otherwise, ignore this message.
FunctionResult successResult = new FunctionResult(true);
if (!_registrations.TryGetValue(functionId, out BlobQueueRegistration registration))
{
Logger.FunctionNotFound(_logger, message.BlobName, functionId, value.MessageId);
return(successResult);
}
var container = registration.BlobServiceClient.GetBlobContainerClient(message.ContainerName);
string blobName = message.BlobName;
BlobBaseClient blob;
BlobProperties blobProperties;
try
{
(blob, blobProperties) = await container.GetBlobReferenceFromServerAsync(blobName, cancellationToken).ConfigureAwait(false);
}
catch (RequestFailedException exception) when(exception.IsNotFound() || exception.IsOk())
{
// If the blob no longer exists, just ignore this message.
Logger.BlobNotFound(_logger, blobName, value.MessageId);
return(successResult);
}
// Ensure the blob still exists with the same ETag.
string possibleETag = blobProperties.ETag.ToString();
// If the blob still exists but the ETag is different, delete the message but do a fast path notification.
if (!string.Equals(message.ETag, possibleETag, StringComparison.Ordinal))
{
_blobWrittenWatcher.Notify(new Extensions.Storage.Blobs.BlobWithContainer <BlobBaseClient>(container, blob));
return(successResult);
}
// If the blob still exists and its ETag is still valid, execute.
// Note: it's possible the blob could change/be deleted between now and when the function executes.
Guid?parentId = await _causalityReader.GetWriterAsync(blob, cancellationToken).ConfigureAwait(false);
// Include the queue details here.
IDictionary <string, string> details = PopulateTriggerDetails(value);
if (blobProperties.CreatedOn != null)
{
details[BlobCreatedKey] = blobProperties.CreatedOn.ToString(Constants.DateTimeFormatString, CultureInfo.InvariantCulture);
}
if (blobProperties.LastModified != null)
{
details[BlobLastModifiedKey] = blobProperties.LastModified.ToString(Constants.DateTimeFormatString, CultureInfo.InvariantCulture);
}
TriggeredFunctionData input = new TriggeredFunctionData
{
ParentId = parentId,
TriggerValue = blob,
TriggerDetails = details
};
return(await registration.Executor.TryExecuteAsync(input, cancellationToken).ConfigureAwait(false));
}
public async Task <FunctionResult> ExecuteAsync(BlobTriggerExecutorContext context, CancellationToken cancellationToken)
{
BlobBaseClient value = context.Blob.BlobClient;
BlobTriggerScanSource triggerSource = context.TriggerSource;
string pollId = context.PollId;
// Avoid unnecessary network calls for non-matches. First, check to see if the blob matches this trigger.
IReadOnlyDictionary <string, object> bindingData = _input.CreateBindingData(value.ToBlobPath());
if (bindingData == null)
{
string pattern = new BlobPath(_input.ContainerNamePattern, _input.BlobNamePattern).ToString();
Logger.BlobDoesNotMatchPattern(_logger, _functionDescriptor.LogName, value.Name, pattern, pollId, triggerSource);
// Blob is not a match for this trigger.
return(new FunctionResult(true));
}
// Next, check to see if the blob currently exists (and, if so, what the current ETag is).
BlobProperties blobProperties = await value.FetchPropertiesOrNullIfNotExistAsync(cancellationToken).ConfigureAwait(false);
string possibleETag = null;
if (blobProperties != null)
{
possibleETag = blobProperties.ETag.ToString();
}
if (possibleETag == null)
{
Logger.BlobHasNoETag(_logger, _functionDescriptor.LogName, value.Name, pollId, triggerSource);
// If the blob doesn't exist and have an ETag, don't trigger on it.
return(new FunctionResult(true));
}
var receiptBlob = _receiptManager.CreateReference(_hostId, _functionDescriptor.Id, value.BlobContainerName,
value.Name, possibleETag);
// Check for the completed receipt. If it's already there, noop.
BlobReceipt unleasedReceipt = await _receiptManager.TryReadAsync(receiptBlob, cancellationToken).ConfigureAwait(false);
if (unleasedReceipt != null && unleasedReceipt.IsCompleted)
{
Logger.BlobAlreadyProcessed(_logger, _functionDescriptor.LogName, value.Name, possibleETag, pollId, triggerSource);
return(new FunctionResult(true));
}
else if (unleasedReceipt == null)
{
// Try to create (if not exists) an incomplete receipt.
if (!await _receiptManager.TryCreateAsync(receiptBlob, cancellationToken).ConfigureAwait(false))
{
// Someone else just created the receipt; wait to try to trigger until later.
// Alternatively, we could just ignore the return result and see who wins the race to acquire the
// lease.
return(new FunctionResult(false));
}
}
string leaseId = await _receiptManager.TryAcquireLeaseAsync(receiptBlob, cancellationToken).ConfigureAwait(false);
if (leaseId == null)
{
// If someone else owns the lease and just took over this receipt or deleted it;
// wait to try to trigger until later.
return(new FunctionResult(false));
}
try
{
// Check again for the completed receipt. If it's already there, noop.
BlobReceipt receipt = await _receiptManager.TryReadAsync(receiptBlob, cancellationToken).ConfigureAwait(false);
Debug.Assert(receipt != null); // We have a (30 second) lease on the blob; it should never disappear on us.
if (receipt.IsCompleted)
{
Logger.BlobAlreadyProcessed(_logger, _functionDescriptor.LogName, value.Name, possibleETag, pollId, triggerSource);
await _receiptManager.ReleaseLeaseAsync(receiptBlob, leaseId, cancellationToken).ConfigureAwait(false);
return(new FunctionResult(true));
}
// We've successfully acquired a lease to enqueue the message for this blob trigger. Enqueue the message,
// complete the receipt and release the lease.
// Enqueue a message: function ID + blob path + ETag
BlobTriggerMessage message = new BlobTriggerMessage
{
FunctionId = _functionDescriptor.Id,
BlobType = blobProperties.BlobType,
ContainerName = value.BlobContainerName,
BlobName = value.Name,
ETag = possibleETag
};
var(queueName, messageId) = await _queueWriter.EnqueueAsync(message, cancellationToken).ConfigureAwait(false);
Logger.BlobMessageEnqueued(_logger, _functionDescriptor.LogName, value.Name, messageId, queueName, pollId, triggerSource);
// Complete the receipt
await _receiptManager.MarkCompletedAsync(receiptBlob, leaseId, cancellationToken).ConfigureAwait(false);
return(new FunctionResult(true));
}
finally
{
await _receiptManager.ReleaseLeaseAsync(receiptBlob, leaseId, cancellationToken).ConfigureAwait(false);
}
}
