public static Task <IStorageBlob> GetBlobReferenceForArgumentTypeAsync(this IStorageBlobContainer container,
string blobName, Type argumentType, CancellationToken cancellationToken)
{
if (argumentType == typeof(CloudBlockBlob))
{
IStorageBlob blob = container.GetBlockBlobReference(blobName);
return(Task.FromResult(blob));
}
else if (argumentType == typeof(CloudPageBlob))
{
IStorageBlob blob = container.GetPageBlobReference(blobName);
return(Task.FromResult(blob));
}
else if (argumentType == typeof(CloudAppendBlob))
{
IStorageBlob blob = container.GetAppendBlobReference(blobName);
return(Task.FromResult(blob));
}
else
{
return(GetExistingOrNewBlockBlobReferenceAsync(container, blobName, cancellationToken));
}
}
public async Task <FunctionResult> ExecuteAsync(IStorageQueueMessage value, CancellationToken cancellationToken)
{
BlobTriggerMessage message = JsonConvert.DeserializeObject <BlobTriggerMessage>(value.AsString, 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);
BlobQueueRegistration registration;
if (!_registrations.TryGetValue(functionId, out registration))
{
return(successResult);
}
IStorageBlobContainer container = registration.BlobClient.GetContainerReference(message.ContainerName);
string blobName = message.BlobName;
IStorageBlob blob;
switch (message.BlobType)
{
case StorageBlobType.PageBlob:
blob = container.GetPageBlobReference(blobName);
break;
case StorageBlobType.AppendBlob:
blob = container.GetAppendBlobReference(blobName);
break;
case StorageBlobType.BlockBlob:
default:
blob = container.GetBlockBlobReference(blobName);
break;
}
// Ensure the blob still exists with the same ETag.
string possibleETag = await _eTagReader.GetETagAsync(blob, cancellationToken);
if (possibleETag == null)
{
// If the blob no longer exists, just ignore this message.
return(successResult);
}
// 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(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);
TriggeredFunctionData input = new TriggeredFunctionData
{
ParentId = parentId,
TriggerValue = blob
};
return(await registration.Executor.TryExecuteAsync(input, cancellationToken));
}