MSIAuthentication could not retrieve a token

[shawnswlin]

Hi,

I'm using Azure Function with Python and managed-identity, but noticed that a MSI: Failed to retrieve a token exception appears many times. Is there any workaround or new build could fix this problem?

Package version:

msrestazure==0.6.1

Trace back:

Exception while executing function: Functions.AzureTimerTrigger Result: Failure
Exception: RuntimeError: MSI: Failed to retrieve a token from 'http://localhost:8081/msi/token/?resource=https://management.core.windows.net/&api-version=2017-09-01' with an error of 'HTTPConnectionPool(host='localhost', port=8081): Max retries exceeded with url: /msi/token/?resource=https://management.core.windows.net/&api-version=2017-09-01 (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7feee2e160f0>: Failed to establish a new connection: [Errno 111] Connection refused',))'.
Stack:   File "/azure-functions-host/workers/python/3.6/LINUX/X64/azure_functions_worker/dispatcher.py", line 315, in _handle__invocation_request
    self.__run_sync_func, invocation_id, fi.func, args)
  File "/usr/local/lib/python3.6/concurrent/futures/thread.py", line 56, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/azure-functions-host/workers/python/3.6/LINUX/X64/azure_functions_worker/dispatcher.py", line 434, in __run_sync_func
    return func(**params)
  File "/home/site/wwwroot/AzureTimerTrigger/main.py", line 84, in main
    compute_client = create_azure_client(ComputeManagementClient, virtual_appliance_subscription)
  File "/home/site/wwwroot/AzureTimerTrigger/main.py", line 306, in create_azure_client
    credentials = MSIAuthentication()
  File "/home/site/wwwroot/.python_packages/lib/python3.6/site-packages/msrestazure/azure_active_directory.py", line 592, in __init__
    self.set_token()
  File "/home/site/wwwroot/.python_packages/lib/python3.6/site-packages/msrestazure/azure_active_directory.py", line 596, in set_token
    self.scheme, _, self.token = get_msi_token_webapp(self.resource, self.msi_conf)
  File "/home/site/wwwroot/.python_packages/lib/python3.6/site-packages/msrestazure/azure_active_directory.py", line 546, in get_msi_token_webapp
    raise RuntimeError(err_msg)

[shawnswlin]

A similar issue has fixed for JS Azure/azure-sdk-for-js#4631

[lmazuel]

Closing, since the recommended approach now is officially to use azure-identity to pull MSI token