Python Azure Function sample showing how to using Input and Output binding with Azure Blob Storage and doing local file manipulation.

iobindingfunction.py

from io import BytesIO
from logging import FileHandler
import logging
import azure.functions as func
from PIL import Image

def main(msg: func.QueueMessage, inputblob: func.InputStream,
         outputblob: func.Out[func.InputStream]) -> None:

    blob_source_raw_name = msg.get_body().decode('utf-8')
    logging.info('Python queue trigger function processed a queue item: %s', blob_source_raw_name)

    # thumbnail filename
    local_file_name_thumb = blob_source_raw_name[:-4] + "_thumb.jpg"

    #####
    # Download file from Azure Blob Storage
    #####
    with open(blob_source_raw_name,"w+b") as local_blob:
        local_blob.write(inputblob.read())

    #####
    # Use PIL to create a thumbnail
    #####
    new_size = 200,200 
    im = Image.open(local_blob.name)
    im.thumbnail(new_size)
    im.save(local_file_name_thumb, quality=95)

    # write the stream to the output file in blob storage
    new_thumbfile = open(local_file_name_thumb,"rb")
    outputblob.set(new_thumbfile.read())