NoneType object error related to Blob storage

Question

After upgrading my azure functions to runtime to ~4, and python to 3.11, as in my previous post https://learn.microsoft.com/en-us/answers/questions/1368325/microsoft-azure-functions-extensionbundle-error-re, they seem to run fine. Except one of them shows the below error, seems to be related to Blob storage:

I then roll back to ~2, python 3.7 (it was 3.6 before upgrading), and similar error still occurs.

Any idea what could be the reason?

Thank you very much!

Answer 1

Mingkai Liu Thanks for sharing the solution in the thread so that it will benefit others experiencing the similar issue. Since the Microsoft Q&A community has a policy that The question author cannot accept their own answer. They can only accept answers by others, I will repost your solution in case you like to accept the answer for greater visibility.

Issue:

After upgrading to Python 3.11/V4 version, you have experienced errors: File is not a zip file and cannot unpack non-iterable NoneType object with the following lines of code: (using pandas library)

try:
        # Retrieve the connection string for use with the application.
        connect_str = os.getenv("flpwrenvirogreendata_Connection_Str")
        logging.info(f"Get connection string: {connect_str}")
        # Create the BlobServiceClient object which will be used to create a container client
        blob_service_client = BlobServiceClient.from_connection_string(connect_str)
        logging.info(f"Created blob service client {blob_service_client}")
        # Create a blob client using the file name as the name for the blob
        blob_client = blob_service_client.get_blob_client(container=container_name, blob=file_name)
        logging.info(f"Created blob client {blob_client}")
        # read  file from blob as binary
        downloader = blob_client.download_blob()
        logging.info(f"downloader {downloader }")
        content_byte = downloader.readall()
        logging.info(f"content_byte{type(content_byte)}")

        try:
            #"pyxlsb" "openpyxl"
            dfs = pd.read_excel(downloader.readall(), sheet_name=None, engine="openpyxl") 
            logging.info(f"read excel {type(content_byte)}")        
        except pd.errors.ParserError as e:
            logging.error("ParserError:", str(e))
        
        
        sheets_name = list(dfs.keys())
        logging.info(f"sheets_name {sheets_name}")
        logging.info(
            f"Read the raw data from  directory in bolb successfulu. Container: {container_name}, File: {file_name}"
        )

        return dfs, sheets_name, content_byte

    except Exception as e:
        logging.error(e)

While debugging, you found the issue was specifically with the line dfs = pd.read_excel(downloader.readall(), sheet_name=None, engine="openpyxl")

Solution:

You have changed the following line of code to use BytesIO to wrap the binary data to resolve the issue.

dfs = pd.read_excel(BytesIO(downloader.readall()), sheet_name=None, engine="openpyxl").