workshop-config

#!/usr/bin/env python

### This program is free software; you can redistribute it and/or
### modify it under the terms of the GNU General Public License
### as published by the Free Software Foundation; either version 2
### of the License, or (at your option) any later version.
###
### This program is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
### GNU General Public License for more details.
###
### You should have received a copy of the GNU General Public License
### along with this program; if not, write to the Free Software
### Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

### Copyright 2014 Dag Wieers <dag@wieers.com>

### This tool is run on boot and provides a configuration window to
### display the system's IP address and set the system's name.
### This is useful when you have a basic image using DHCP which can
### be cloned at will as many times to have a group of systems to
### demo or learn a configuration system.

import ethtool, fcntl, os, sys, termios, tty
from snack import Entry, GridForm, Label, Listbox, SnackScreen

names = ( 'vm-master', 'vm-web', 'vm-db', 'vm-syslog', 'vm-kdump' )
system = os.uname()[1].split('.')[0]
domain = 'example.net'

def ipaddress():
    '''Return the first acceptable IP address on the hostonly network'''
    for dev in ethtool.get_active_devices():
        if (ethtool.get_flags(dev) & (ethtool.IFF_LOOPBACK | ethtool.IFF_POINTOPOINT)):
            continue
        for addr in ethtool.get_interfaces_info(dev)[0].get_ipv4_addresses():
            return addr.address

    return '<unknown>'

def set_tty(nr):
    '''Move application to a different console'''
    fd = open('/dev/tty%d' % nr, 'a')
    old = termios.tcgetattr(fd)
    new = termios.tcgetattr(fd)
    new[0] = new[0] & ~termios.ICRNL
    new[3] = new[3] & ~(termios.ICANON | termios.ECHO)
    new[3] = new[3] | termios.ISIG
    termios.tcsetattr(fd, termios.TCSAFLUSH, new)
    tty.setraw(fd)
    os.closerange(0, 3)
    os.dup2(fd.fileno(), sys.stdin.fileno())
    os.dup2(fd.fileno(), sys.stdout.fileno())
    os.dup2(fd.fileno(), sys.stderr.fileno())

def chvt(nr):
    '''Change to a different console'''
    fd = open('/proc/self/fd/0')
    fcntl.ioctl(fd, 0x00005606, nr)
    fcntl.ioctl(fd, 0x00005607, nr)

try:
    tty_nr = int(sys.argv[1])
except IndexError:
    tty_nr = None
except ValueError:
    print >>sys.stderr, "ERROR: Argument %s is not a number" % sys.argv[1]
    sys.exit(1)

if tty_nr != None:
    set_tty(tty_nr)

screen = SnackScreen()
screen.drawRootText(17, 1, 'Welcome to the Ansible Workshop configurator !')
screen.pushHelpLine('Change or select hostname')

hostname = Entry(15, system)
listbox = Listbox(height = len(names), width = 18, returnExit = 1)
for nr, name in enumerate(names):
    listbox.append(name, nr)
    if name == system:
        listbox.setCurrent(names.index(system))

grid = GridForm(screen, "Virtual Machine", 1, 5)
grid.add(Label('Hostname:'), 0, 2, anchorLeft=1)
grid.add(hostname, 0, 3, anchorRight=1)
grid.add(Label('IP Address:'), 0, 0, anchorLeft=1)
grid.add(Label(ipaddress()), 0, 1, anchorRight=1)
grid.add(listbox, 0, 4, padding=(0, 1, 0, 0))

if tty_nr != None:
    chvt(tty_nr)

while True:
    hostname.set(system)
    result = grid.run()
    system = names[listbox.current()]
    try:
        open('/proc/sys/kernel/hostname', 'w').write(system)
        open('/etc/sysconfig/network', 'w').write('NETWORKING=yes\nHOSTNAME=%s.%s\n' % (system, domain))
        open('/etc/hostname', 'w').write('%s.%s\n' % (system, domain))
        screen.pushHelpLine('Configured!')
    except:
        screen.pushHelpLine('Error changing system name')