Comment 0 for bug 1684349

 mask2cidr error with integer value - argument of type 'int' is not iterable

~~~
def mask2cidr(mask):
    if ':' in str(mask):
        return ipv6mask2cidr(mask)
    elif '.' in mask:
        return ipv4mask2cidr(mask)
    else:
        return mask
~~~

is not type safe. It tries to take into account that this can be a prefix (so it does not contain ':' not '.' and then return mask. The problem is that if mask is an integer, then this returns:

~~~
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/cloudinit/cmd/main.py", line 513, in status_wrapper
    ret = functor(name, args)
  File "/usr/lib/python2.7/site-packages/cloudinit/cmd/main.py", line 269, in main_init
    init.apply_network_config(bring_up=bool(mode != sources.DSMODE_LOCAL))
  File "/usr/lib/python2.7/site-packages/cloudinit/stages.py", line 641, in apply_network_config
    return self.distro.apply_network_config(netcfg, bring_up=bring_up)
  File "/usr/lib/python2.7/site-packages/cloudinit/distros/__init__.py", line 150, in apply_network_config
    dev_names = self._write_network_config(netconfig)
  File "/usr/lib/python2.7/site-packages/cloudinit/distros/rhel.py", line 59, in _write_network_config
    ns = parse_net_config_data(netconfig)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 32, in parse_net_config_data
    nsi.parse_config(skip_broken=skip_broken)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 205, in parse_config
    handler(self, command)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 78, in decorator
    return func(self, command, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 239, in handle_physical
    subnet['netmask'] = mask2cidr(subnet['netmask'])
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 441, in mask2cidr
    elif '.' in mask:
~~~

Made a modification to the code to troubleshoot this:
~~~
       # convert subnet ipv6 netmask to cidr as needed
        subnets = command.get('subnets')
        print subnets
        if subnets:
            for subnet in subnets:
                if subnet['type'] == 'static':
                    if 'netmask' in subnet and ':' in subnet['address']:
                        subnet['netmask'] = mask2cidr(subnet['netmask'])
                        for route in subnet.get('routes', []):
                            if 'netmask' in route:
                                route['netmask'] = mask2cidr(route['netmask'])
~~~

This error can be hit on RHEL when running the following 2x (don't know why 2x):

 rm -Rf /var/lib/cloud/data/* ; cloud-init --force init

On the second run, this will be returned:
~~~
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/cloudinit/cmd/main.py", line 513, in status_wrapper
    ret = functor(name, args)
  File "/usr/lib/python2.7/site-packages/cloudinit/cmd/main.py", line 269, in main_init
    init.apply_network_config(bring_up=bool(mode != sources.DSMODE_LOCAL))
  File "/usr/lib/python2.7/site-packages/cloudinit/stages.py", line 641, in apply_network_config
    return self.distro.apply_network_config(netcfg, bring_up=bring_up)
  File "/usr/lib/python2.7/site-packages/cloudinit/distros/__init__.py", line 150, in apply_network_config
    dev_names = self._write_network_config(netconfig)
  File "/usr/lib/python2.7/site-packages/cloudinit/distros/rhel.py", line 59, in _write_network_config
    ns = parse_net_config_data(netconfig)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 32, in parse_net_config_data
    nsi.parse_config(skip_broken=skip_broken)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 205, in parse_config
    handler(self, command)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 78, in decorator
    return func(self, command, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 239, in handle_physical
    subnet['netmask'] = mask2cidr(subnet['netmask'])
  File "/usr/lib/python2.7/site-packages/cloudinit/net/network_state.py", line 441, in mask2cidr
    elif '.' in mask:
TypeError: argument of type 'int' is not iterable
------------------------------------------------------------
[{u'routes': [{u'netmask': u'0.0.0.0', u'network': u'0.0.0.0', u'gateway': u'192.168.0.1'}], u'netmask': u'255.255.255.0', u'type': 'static', 'ipv4': True, 'address': u'192.168.0.11'}, {u'routes': [{u'netmask': 0, u'network': u'::', u'gateway': u'2000:192:168::1'}], u'netmask': 64, 'ipv6': True, u'type': 'static', 'address': u'2000:192:168::4'}]
~~~

not the `u'netmask': 64` integer

This can be fixed by changing the code to:
~~~
def mask2cidr(mask):
    if ':' in str(mask):
        return ipv6mask2cidr(mask)
    elif '.' in str(mask):
        return ipv4mask2cidr(mask)
    else:
        return mask
~~~