get the inner or public ip addr for linux sys

get_ip.py

# coding=utf-8


def get_ip(inner=True):
    """
    get local ip addr
       default get inner ip address, set `inner` to False to
          get public ip if exists, or it will return None
       it returns 'localhost' when failed
    """
    import re
    ip_list = []

    def is_inner_ip(x):
        ip_lst = x.split(".")
        if len(ip_lst) != 4:
            return False
        if ip_lst[0] == "10":
            return True
        if ip_lst[:2] == ["192", "168"]:
            return True
        if ip_lst[0] == "172" and 16 <= int(ip_lst[1]) <= 31:
            return True
        return False
    try:
        from netifaces import interfaces, ifaddresses, AF_INET
        for interface in interfaces():
            try:
                links = ifaddresses(interface)[AF_INET]
            except KeyError:
                continue
            for link in links:
                ip_list.append(link['addr'])
    except ImportError:
        try:
            import subprocess
            _null = open('/dev/null', 'a')
            ip_list = subprocess.Popen(
                "/sbin/ifconfig|grep 'inet '|awk '{print $2}'",
                stdout=subprocess.PIPE, stderr=_null,
                shell=True).communicate()[0].split('\n')
            _null.close()
            ip_list = [re.sub("^.*?(\d+\.\d+\.\d+\.\d+).*$", r"\1", itm) for itm in ip_list]
        except:
            ip_list = []
    ip_list = filter(lambda x: re.match('^(\d+\.){3}\d+$', x) and x!='127.0.0.1', ip_list)
    inner_list = []
    outter_list = []
    for ip in ip_list:
        if is_inner_ip(ip):
            inner_list.append(ip)
        else:
            outter_list.append(ip)
    if not ip_list:
        return "localhost"
    if inner:
        return inner_list[-1] if inner_list else outter_list[-1]
    else:
        return outter_list[-1] if outter_list else None

if __name__ == '__main__':
    print 'inner ip:', get_ip()
    print 'pub ip:', get_ip(False)

it can perform better with module netifaces