v4.0.0 and higher: AttributeError: 'NoneType' object has no attribute 'proxy_info' when attempting to connect to DFP using a service account.

Expected behavior

A service account with suitable privileges assigned should be able to connect to DFP services

Actual behavior

Attempts to connect to DFP with a valid service account result in Python AttributeError, apparently because GoogleServiceAccountClient.Refresh.proxy_config returns None.

Information

Some of my code started failing following googleads upgrade. To isolate the behavior to googleads, I composed the following simple test case, to connect to the DFP network service (based mainly on copy and paste from https://github.com/googleads/googleads-python-lib/tree/master/examples/dfp)

from googleads import dfp
from googleads import oauth2

# OAuth2 credential information. In a real application, you'd probably be
# pulling these values from a credential storage.
SERVICE_ACCOUNT_EMAIL = '[e-mail]'
KEY_FILE = '/secret/gcskey.p12'

# DFP API information.
APPLICATION_NAME = 'fake-pretend'


def dfp_api_client():

    oauth2_client = oauth2.GoogleServiceAccountClient(
            oauth2.GetAPIScope('dfp'), SERVICE_ACCOUNT_EMAIL, KEY_FILE)
    dfp_client = dfp.DfpClient(oauth2_client, APPLICATION_NAME)
    return dfp_client


def main(client):
    # directly from https://github.com/googleads/googleads-python-lib/blob/master/examples/dfp/v201602/network_service/get_all_networks.py
    # Initialize appropriate service.
    network_service = client.GetService('NetworkService', version='v201602')

    # Get all networks that you have access to with the current login credentials.
    networks = network_service.getAllNetworks()

    # Display results.
    for network in networks:
        print ('Network with network code \'%s\' and display name \'%s\' was found.'
             % (network['networkCode'], network['displayName']))

    print '\nNumber of results found: %s' % len(networks)

if __name__ == '__main__':
  # Initialize client object.
  dfp_client = dfp_api_client()
  main(dfp_client)

This works entirely as expected at v3.15.0, but fails with the following traceback with v4.0.0 and higher:

Traceback (most recent call last):
  File "api-test.py", line 37, in <module>
    dfp_client = dfp_api_client()# dfp.DfpClient.LoadFromStorage()
  File "api-test.py", line 16, in dfp_api_client
    oauth2.GetAPIScope('dfp'), SERVICE_ACCOUNT_EMAIL, KEY_FILE)
  File "/Users/thomas/.virtualenvs/tmp-1e8b453a8dbebace/lib/python2.7/site-packages/googleads/oauth2.py", line 203, in __init__
    self.Refresh()
  File "/Users/thomas/.virtualenvs/tmp-1e8b453a8dbebace/lib/python2.7/site-packages/googleads/oauth2.py", line 236, in Refresh
    proxy_info=self.proxy_config.proxy_info,
AttributeError: 'NoneType' object has no attribute 'proxy_info'

Steps to reproduce

1. Install googleads 3.15.0
2. Attempt connection to DFP API using a service account, which should work
3. upgrade to googleads 4.x
4. Attempt connection again

[nicholaschen]

My colleague Mark has found the issue, and is going to release this with the next lib push.

Thanks for your patience!

[msaniscalchi]

Closing as this has been open for some time without any response, feel free to reopen if it remains reproducible and you can provide additional information.

Regards, Mark