Avoid using network at import time

[hauntsaninja]

The latest version of msal can open sockets at import time as part of DNS resolution
This is from 95ccef0#diff-24c0727ff4626c6c535d05c13b61fa4b4a47d6fc4496ec0ceadc734191de19cbR128
cc @rayluo

[rayluo]

Hi @hauntsaninja , can you share your code snippet to reproduce the issue? I tried the snippet below but did not see any network traffic.

from http.client import HTTPConnection
import logging

HTTPConnection.debuglevel = 1
logging.basicConfig()
logging.getLogger().setLevel(logging.DEBUG)

import msal

[hauntsaninja]

One easy way to check is to use strace (on Linux):

λ strace -e trace=connect python -c 'import msal'                                  
connect(3, {sa_family=AF_UNIX, sun_path="/var/run/nscd/socket"}, 110) = -1 ENOENT (No such file or directory)
connect(3, {sa_family=AF_UNIX, sun_path="/var/run/nscd/socket"}, 110) = -1 ENOENT (No such file or directory)
+++ exited with 0 +++

Source is the socket.getfqdn here (class variable assignments run at import time):

microsoft-authentication-library-for-python/msal/managed_identity.py

Line 147 in c1ead1c

_instance, _tenant = socket.getfqdn(), "managed_identity" # Placeholders