Azure Function(Python Runtime): Local development store environment variable

Question

I'm creating an Azure Function with Python 3.9 runtime. The function is a timer triggered function that will read credentials from Azure Key Vault, and call the rest api accordingly. In the azure documentation, it is shown the best approach will be to store the key vault url in an environment variable. I have tried to store the key vault url value in local.settings.json, and tried to access it using os.environ() dictionary, but I'm not able to access the url.

Can anyone please help me to understand, what can be the best approach to store environment variable when I'm developing azure function locally(using Visual Studio Code) using Python runtime, so that I don't have to change the code to access the value in azure function(in azure cloud) as well as when I'm developing locally?

Answer 1

@Yash Thank you for reaching out. I have tested the scenario in my local environment by creating the Timmer trigger function, stored the key Vault name as environment variable in the local.settings.json file. As documented here I have used os.environ() to get the key vault name and was able to retrieve the secrets.

init.py:

import datetime  
import logging  
import os  
from azure.keyvault.secrets import SecretClient  
from azure.identity import DefaultAzureCredential  
  
import azure.functions as func  
  
def main(mytimer: func.TimerRequest) -> None:  
    utc_timestamp = datetime.datetime.utcnow().replace(  
    tzinfo=datetime.timezone.utc).isoformat()  
  
    keyVaultName = os.environ["KEY_VAULT_NAME"]  
    KVUri = fhttps://{keyVaultName}.vault.azure.net  
    credential = DefaultAzureCredential()  
    client = SecretClient(vault_url=KVUri, credential=credential)  
    secret=client.get_secret("keytest")  
    logging.info(secret.value)  
    logging.info('Python timer trigger function ran at %s', utc_timestamp)  

local.setting.json:

{  
  "IsEncrypted": false,  
  "Values": {  
    "AzureWebJobsStorage": "<<yourstorageconnectionstring>>",  
    "FUNCTIONS_WORKER_RUNTIME": "python",  
    "KEY_VAULT_NAME":"<<yourkeyvalutname>>"  
  }  
}  

requirements.txt

azure-functions  
azure-identity  
azure-keyvault  
azure-keyvault-secrets  

Output:

Can anyone please help me to understand, what can be the best approach to store environment variable when I'm developing azure function locally(using Visual Studio Code) using Python runtime, so that I don't have to change the code to access the value in azure function(in azure cloud) as well as when I'm developing locally?

It is always recommended to store the environment variables in local.settings.json file during your local development but when deploying to function make sure your local.settings.json settings are reflected/uploaded in the configuration blade of your function app.

Feel free to get back to me if you need any assistance.