Check Existence of Blob based on Pattern match in Azure Blob Storage using Python in Azure Functions

Question

Is there a way to check if file exists in a Azure BLOB container using Python based on pattern using Azure Function? I have different files incoming and I need to process them based on "FileName" Parameter. The Files dropped on the container would come with appended date. I need to check if the file Exists, then work over it.

Sample Files at container =>

1. API_File1_20202008.CSV

2. API_File2_20202008.CSV

3. API_File3_20202008.CSV

If Parameter passed in Function = > API_File1.
Then the function should check if any blob in a specified with API_File1* exists, then process.

For Local OS I was able to use the following.

for name in glob.glob(SourceFolder +'/' + FileName + '*.CSV'):
    print(name)

Any suggestion?

Answer 1

For this requirement, you can use the code below to implement it on azure.

import logging

import azure.functions as func
from azure.storage.blob.blockblobservice import BlockBlobService


def main(req: func.HttpRequest) -> func.HttpResponse:
    logging.info('Python HTTP trigger function processed a request.')

    #just focus on below part
    block_blob_service = BlockBlobService(account_name="<your storage name>", account_key="<storage key>")

    if block_blob_service.exists("<container name>", "file5.csv"):
            print("========found file=======");
    else:
            print("========not exist========");
    #just focus on the part above

    name = req.params.get('name')
    if not name:
        try:
            req_body = req.get_json()
        except ValueError:
            pass
        else:
            name = req_body.get('name')

    if name:
        return func.HttpResponse(f"Hello, {name}. This HTTP triggered function executed successfully.")
    else:
        return func.HttpResponse(
             "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response.",
             status_code=200
        )

Before run the code, you need to install the modules. Do not install pip install azure-storage-blob , I test with install azure-storage-blob but it occurs some problem. You can install pip install azure==4.0.0 (it may take some time) in your virtual environment in "Terminal" window, and then the code can run success.

=================================== Update ==================================

I don't think we can query the file name by "File5" + "*.CSV" directly. But I can provide a workaround for your reference. Then function get the request parameter fileName and then use the code below:

files = [blob for blob in block_blob_service.list_blobs("testcontainer") if blob.name.startswith(fileName)]

for file in files:
    logging.info(file.name)

The code is used to get all of the file which start with the fileName you send to the function.