Get Progress in Python file Upload to Azure

Question

i'm uploading files to azure like so:

with open(tempfile, "rb") as data:
    blob_client.upload_blob(data, blob_type='BlockBlob',  length=None, metadata=None)

how can i get a progress indication? when i try uploading as stream, it only uploads one chunk.

i'm sure i'm doing something wrong, but can't find info.

thanks!

Answer 1

It looks like the Azure library doesn't include a callback function to monitor progress.

Fortunately, you can add a wrapper around Python's file object which can call a callback everytime there's a read.

Try this:

import os
from io import BufferedReader, FileIO


class ProgressFile(BufferedReader):
    # For binary opening only

    def __init__(self, filename, read_callback):
        f = FileIO(file=filename, mode='r')
        self._read_callback = read_callback
        super().__init__(raw=f)

        # I prefer Pathlib but this should still support 2.x
        self.length = os.stat(filename).st_size

    def read(self, size=None):
        calc_sz = size
        if not calc_sz:
            calc_sz = self.length - self.tell()
        self._read_callback(position=self.tell(), read_size=calc_sz, total=self.length)
        return super(ProgressFile, self).read(size)



def my_callback(position, read_size, total):
    # Write your own callback. You could convert the absolute values to percentages
    
    # Using .format rather than f'' for compatibility
    print("position: {position}, read_size: {read_size}, total: {total}".format(position=position,
                                                                                read_size=read_size,
                                                                                total=total))


myfile = ProgressFile(filename='mybigfile.txt', read_callback=my_callback)

Then you would do

blob_client.upload_blob(myfile, blob_type='BlockBlob',  length=None, metadata=None)

myfile.close()

Edit: It looks like TQDM (progress monitor) has a neat wrapper: https://github.com/tqdm/tqdm#hooks-and-callbacks. The bonus there is that you get easy access to a pretty progress bar.