Azure Function Downloading file to Azure Virtual file share

Question

Azure Function Downloading file to Azure Virtual file share

Adrian Griffith 61

Access to the path '\fileserver1.domain.com\directory\sub-directory' is denied. fileserver1.domain.com is a Azure VM

Users upload a file to be processed to our "azure file share" and send a request to "azure queue". That request tells us there is a file to be processed and to validate the file. Once validated, the file is downloaded to to a "shared directory" on the "azure VM file server" for processing.

I am using the Legacy SDK CloudFile.DownloadToFileAsync to copy the file. I did not see this capability in the newer "File Share" api.

As you can see, I am getting a permission error when I run from/within azure versus my own desktop. The code works using a "shared directory" on my desktop. It works with a "shared directory" on fileserver1.domain.com if I execute from my desktop. I have permissions.

Who, and how, do I grant permissions to the account executing my Azure Function. How do I grant my function the ability to write to my file server.

Thanks

Adrian Griffith 61 Reputation points

2022-06-13T13:43:52.38+00:00

Moving on to try SFTP access to Blobs.

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Adrian Griffith 61 Reputation points

2022-06-13T13:43:52.38+00:00

Moving on to try SFTP access to Blobs.

Answer 1

MughundhanRaveendran-MSFT 12,506

@Adrian Griffith ,

Thanks for reaching out to Q&A.

The code works in your local machine as you have write permissions on the shared directory in your desktop. However, there are restrictions in the Functions file system as it is a sanboxed environment.

File systems restrictions and considerations : https://github.com/projectkudu/kudu/wiki/Azure-Web-App-sandbox#file-system-restrictionsconsiderations

The long term solution for your problem is to download and move the files to an Azure storage account.

I hope this helps! Feel free to reach out to me if you have any further queries or concerns.

Adrian Griffith 61 Reputation points

2022-03-14T15:01:41.417+00:00

Thank you Mughundhan Raveendran!

But but but ... lol ... I have an Azure Function attempting to write a file on a Azure VM. We have an Azure VNET and Azure AD. But the Azure function is "sandboxed" and there is no way to write the file to a shared drive on an Azure VM?

There is no way to leverage .... Virtual Networks
Azure Web Apps may set up their virtual networks, or VNets in order to facilitate connectivity between Azure and on-premise intranets. This special case of network connectivity is also handled differently in the sandbox. In particular, the aforementioned restrictions on private and local addresses are ignored if the target network interface belongs to the app. Other VNet adapters on the same machine cannot be accessed, and all other network limitations are still apply.

Additionally, the sandbox automatically affinitizes connect and send operations destined for VNet addresses to the correct VNet interface, in order to improve ease-of-use of the VNet feature.

Is it possible to write an "Socket Listener" on the destination machine and use a Azure Hybrid Connection Manager? I assume so since it is the listener doing the writing to the local file system
Adrian Griffith 61 Reputation points

2022-03-15T17:21:49.827+00:00

Must I mount a drive to write to a file, say '\fileserver1.domain.com\directory\sub-directory'?

I am thinking the Azure Function communicating with a Hybrid Connection to fileserver1 SMB port. I don't have the experience to say if this is worth pursuing or not. Hoping you would.

Thank you!
MughundhanRaveendran-MSFT 12,506 Reputation points

2022-03-16T07:40:45.367+00:00

@Adrian Griffith , I am discussing this internally. I will get back to you with an update.
Adrian Griffith 61 Reputation points

2022-03-18T14:09:40.54+00:00

Dang ... so I have attempted to use FTP over a Hybrid Connection for port 21. I thought this would work. FTP/SFTP/FTPS are socket based (like SQL Server). That is what hybrid connections are to provide. A means for socket based communication without opening your firewall.

This is a certificate problem (for which I have no control over): RemoteCertificateNameMismatch, I respond with true. This works locally but not as an Azure Function. Maybe we are just not ready to move to the cloud.

The server committed a protocol violation at System.Net.FtpWebRequest.SyncRequestCallback(Object obj)
at System.Net.CommandStream.InvokeRequestCallback(Object obj)
at System.Net.CommandStream.Abort(Exception e)
at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage)
at System.Net.FtpWebRequest.GetResponse()
at ProcessSalesforceData.Manager.Repositories.FtpStorageRepository.CopyAsync(String sourcePathAndFile, String destinationPathAndFile, String fileShare) in D:\a\8\s\Production\Services\ProcessSalesforceData\trunk\ProcessSalesforceData.Manager\Repositories\FtpStorageRepository.cs:line 56
at ProcessSalesforceData.Manager.FileStorageManager.CopyAsync(QueueRequest queueRequest, ProjectInformation projectInfo) in D:\a\8\s\Production\Services\ProcessSalesforceData\trunk\ProcessSalesforceData.Manager\FileStorageManager.cs:line 41
at ProcessSalesforceData.Manager.ProcessRequestManager.ProcessRequestAsync(QueueRequest queueRequest) in D:\a\8\s\Production\Services\ProcessSalesforceData\trunk\ProcessSalesforceData.Manager\ProcessRequestManager.cs:line 54

Answer 2

Adrian Griffith 61

Moving on to try SFTP access to Blobs.

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Azure Function Downloading file to Azure Virtual file share

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