Salt grain for discovering primary IP address on a Linux machine.

primary_ip.py

#!/usr/bin/env python
import subprocess

def linux_get_primary_ip4():
    grains = {}

    try:
        defroute_device = subprocess.check_output("ip route | grep default | grep -Eo 'dev\s+\w+' | awk '{print $2}'", shell=True).strip()
        devip = subprocess.check_output("ip a s {0} | grep -E 'inet\s' | cut -d'/' -f1 | awk '{{print $2}}'".format(defroute_device), shell=True).strip()
    except subprocess.CalledProcessError as e:
        return

    if devip is not None or not devip == "":
        grains['primary_ip4'] = devip

    return grains