How to write API response to Azure Blobstorage

Question

I am developing an Azure function blob trigger to read a column from CSV in a blob and pass column values to API request to get JSON response of each value, I want to write each response to Azure blob storage in a new .JSON file.

Here is my code

    import logging
    import azure.functions as func
    from azure.storage.blob import BlobServiceClient,BlobClient
    import pandas as pd
    import requests
    import json
    import os, io
    
    
    def main(inputBlob: func.InputStream, outputBlob: func.Out[str]):
        logging.info(f"Blob trigger executed!")
        logging.info(f"Blob Name: {inputBlob.name} ({inputBlob.length}) bytes")
        logging.info(f"Full Blob URI: {inputBlob.uri}")
    
    
        # connections
        connection_string  = "DefaultEndpointsProtocol=https;AccountName=nhtsa;AccountKey=*********==;EndpointSuffix=core.windows.net"
        containerName = "myblobcontainer"
        blobName = "input/NHTSA_Inbound.csv"
        out_blob = "output"
        blob = BlobClient.from_connection_string(conn_str=connection_string, container_name=containerName, blob_name=blobName)
      
        # reading csv column values and pass into   request to get each value response 

        blobStream = blob.download_blob().content_as_bytes()
        logging.info(blobStream)
        df = pd.read_csv(io.BytesIO(blobStream), sep=',', dtype=str)
        vin_df = pd.DataFrame(df['vin'])
        vin_tup = list(vin_df.to_records(index=False))
        for i,t in enumerate(vin_tup):
            nhtsa_url = 'https://vpic.nhtsa.dot.gov/api/vehicles/DecodeVinValuesExtended/%s?format=json&modelyear=2011'%t[0]
            nhtsa_req_content = requests.get(nhtsa_url)
            nhtsa_data = nhtsa_req_content.json()
            with open(os.path.join(outputBlob,'Veh_%s.json'%t[0]),"w+") as output_file:
                json.dump(list(list(nhtsa_data.values())[0]),output_file)

Everything was working fine except the file write section. I am debugging function in my VS Code and my breakpoint is throwing error at this location

with open(os.path.join(outputBlob,'Veh_%s.json'%t[0]),"w+") as output_file: json.dump(list(list(nhtsa_data.values())[0]),output_file)

error
Executed 'Functions.BlobTrigger1' (Failed, Id=8c1dd2bb-7fb9-4670-9f44-4fb290530325, Duration=34741ms)
[2021-05-15T15:51:01.978Z] System.Private.CoreLib: Exception while executing function: Functions.BlobTrigger1. System.Private.CoreLib: Result: Failure
Exception: TypeError: expected str, bytes or os.PathLike object, not Out
Stack:   File "C:\Program Files\Microsoft\Azure Functions Core Tools\workers\python\3.7/WINDOWS/X64\azure_functions_worker\dispatcher.py", line 372, in _handle__invocation_request
    self.__run_sync_func, invocation_id, fi.func, args)
  File "C:\Program Files\Python37\lib\concurrent\futures\thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "C:\Program Files\Microsoft\Azure Functions Core Tools\workers\python\3.7/WINDOWS/X64\azure_functions_worker\dispatcher.py", line 548, in __run_sync_func
    return func(**params)
  File "C:\Users\yyy1u39\Desktop\Campaign Group Dashboard\Portfolio\Azure Data Factory\BlobTrigger1\__init__.py", line 35, in main
    with open(os.path.join(outputBlob,'Veh_%s.json'%t[0]),"w+") as output_file:
  File "C:\Program Files\Python37\lib\ntpath.py", line 76, in join
    path = os.fspath(path)
.

 

Answer 1

It is recommended to use Azure storage blob SDK to upload multiple request results instead of Azure function blob output binding.

Just try the code below:

import requests
from azure.storage.blob import ContainerClient

#skip reading csv 

#Call demo API and save result individually 
requestURLs =['https://reqres.in/api/users?page=1','https://reqres.in/api/users?page=2']
storageConnStr = ''
containerName =''
container_client = ContainerClient.from_connection_string(storageConnStr,containerName)
count = 0

for req in requestURLs:
    result = requests.get(req).text
    container_client.get_blob_client('output/req'+ str(count) + '.json').upload_blob(result)
    count+=1

Result:

Let me know if you have any more questions.