Unable to download blobs from azure blob storage

0
votes

i'm trying to download blob from sub-directory of azure blob . i'm only able to download few files but for remaining it is throwing "HTTP status code=416, Exception=The range specified is invalid for the current size of the resource. ErrorCode: InvalidRange" . i am able to directly download the blobs from azure but programmatically only few were downloaded

3
pythonazure-blob-storage
Welcome to the site. Please add more details about your current python implementation. - EmJ
Please add the code and what specifically you're trying to accomplish. Are the blobs within a virtual folder, or a container, also did you speciffy any range/size limits for the blobs to be downloaded ? - Adam Smith - Microsoft Azure

3 Answers

2
votes

I got this error, when I tried to download an empty blob. Using Peter Pan's code, you need to add a check for emptiness.

blob_info = blob_service.get_blob_properties(container_name, blob_name)
if blob_info.properties.content_length == 0:
    return "empty blob"
0
votes

Here is the description about your error, please refer to the offical document Common REST API Error Codes for Storage Services.

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Due to there is not any code in your description, I post my sample code as reference at here.

from azure.storage.blob.baseblobservice import BaseBlobService

import os

account_name = '<your account name>'
account_key = '<your account key>'

blob_service = BaseBlobService(
    account_name=account_name,
    account_key=account_key
)

container_name = '<your container name, such as `test`'

# Virtual Directory Name as the prefix string of a blob name
prefix = '<the blob name prefix, such as `images`>' 

# local directory path for downloading blobs
local_path = '<a local directory path for downloading, such as `download`>' 

blobs = blob_service.list_blobs(container_name, prefix=prefix)

for blob in blobs:
    blob_name = blob.name
    blob_base_name = os.path.basename(blob_name)
    file_path = '%s/%s' % (local_path, blob_base_name)
    blob_service.get_blob_to_path(container_name, blob_name, file_path)

Hope it helps.

0
votes

Most likely you get these exceptions for blobs with zero length. Here (Microsoft Azure Storage SDK for Python issues: https://github.com/Azure/azure-storage-python/issues/586) they say that you are safe to ignore these exceptions - catch and swallow. Such files are still downloaded correctly:

I believe this error is shown when you try to download a zero-length blob. You can get around it by checking the blob properties prior to trying the download, or alternatively just let it happen - the file is downloaded as it should be anyway.

I verified it and can confirm that zero-length files are downloaded correctly if these exceptions are swallowed.