why can not get the local IP with configparser in python

Question

I run this python. everything is fine.

import socket
import sys
def get_local_ip(ifname):
    print type(ifname)
    import fcntl, struct 
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 
    inet = fcntl.ioctl(s.fileno(), 0x8915, struct.pack('256s', ifname[:15])) 
    ret = socket.inet_ntoa(inet[20:24]) 
    return ret 

out put

<type 'str'>
192.168.1.250

But I tried to set a config file

here is my config file socketConfig.conf

[config]
ethname = 'eth0'

here is the python code

import socket
import sys
import configparser
conf = configparser.ConfigParser()
conf.read("socketConfig.conf")


def get_local_ip(ifname):
    print type(ifname)
    import fcntl, struct 
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 
    inet = fcntl.ioctl(s.fileno(), 0x8915, struct.pack('256s', ifname[:15])) 
    ret = socket.inet_ntoa(inet[20:24]) 
    return ret

eth = conf.get('config', 'ethname').encode('utf-8')
print get_local_ip(eth)

then out put these error

<type 'str'>
Traceback (most recent call last):
  File "socketClient.py", line 28, in <module>
    print get_local_ip(eth)
  File "socketClient.py", line 23, in get_local_ip
    inet = fcntl.ioctl(s.fileno(), 0x8915, struct.pack('256s', ifname[:15]))
IOError: [Errno 19] No such device

Is anyone knows what is going on? thank you.

Answer 1

The quotes are being picked up as part of the configuration option.

Your configuration file should look like this;

[config]
ethname = eth0

Note the omission of quotes.