WIP Ansible /etc/network/interfaces module

interfaces.py

#!/usr/bin/python

import os
import json

def update(module, state, name, auto, hotplug, iface_type, addr_family, address,
           netmask, nameservers, gateway):
    try:
        fd = open('/etc/network/interfaces')

        iface = ""
        addr_family = ""
        results = {}
        ignored = []

        for line in fd:
            fields = line.split()

            if not fields:
                continue
            elif fields[0] in ['auto', 'allow-hotplug']:
                iface = fields[1]

                if iface not in results.keys():
                    results[iface] = {}

                results[iface].update({fields[0]: True})
            elif fields[0] == 'iface':
                iface = fields[1]
                addr_family = fields[2]

                if iface not in results.keys():
                    results[iface] = {}

                results[iface].update(
                    {
                        'addr_family': {addr_family: {}},
                        'iface_type': fields[3]
                    }
                )
            elif fields[0] in [
                    'address', 'netmask', 'gateway', 'up', 'down',
                    'pre-up', 'post-up', 'pre-down', 'post-down',
                    'dns-nameservers']:

                # In an interface block?
                if not iface:
                    ignored.append(line.strip())
                    continue

                entry = fields[0]
                rest = " ".join(fields[1:])
                entries = results[iface]['addr_family'][addr_family]

                # Store these as a list
                if entry.startswith(('pre','post','up','down')):
                    if not entry in entries:
                        entries[entry] = []

                    entries[entry].append(rest)
                # The rest are unique
                else:
                    entries.update({entry: rest})
            else:
                ignored.append(line.strip())

        # Close file so we copy over it
        fd.close()

        # Truncate
        fd = open('/etc/network/interfaces.tmp', 'w')
        fd.write('# This file is controlled by ansible\n')

        # Build basic structure
        entry = {
            'auto': auto,
            'allow-hotplug': hotplug,
            'iface_type': iface_type,
            'addr_family': {addr_family: {}}
        }

        # Add iface directives
        for key in {
                'address': address,
                'netmask': netmask,
                'gateway': gateway,
                'dns-namservers': nameservers
        }.items():
            if key[1]:
                entry['addr_family'][addr_family].update({key[0]: key[1]})

        # Default
        changed = False

        # Handle state request
        if state == 'present':
            if not name in results.keys() or results[name] != entry:
                changed = True
                results[name] = entry
        elif state == 'absent':
            if name in results.keys():
                changed = True
                results[name] = {}

        # Write it out
        for iface in sorted(results.keys(), reverse=True):
            for directive in sorted(results[iface].keys(), reverse=True):
                if directive in ['auto', 'allow-hotplug'] \
                and results[iface][directive]:
                    fd.write('%s %s' % (directive, iface) + '\n')
                elif directive in ['addr_family']:
                    addr_families = results[iface][directive]
                    for addr_family in sorted(addr_families.keys()):
                        fd.write(
                            'iface %s %s %s' % (
                                iface,
                                addr_family,
                                results[iface]['iface_type']
                            )
                            + '\n'
                        )
                        entries = addr_families[addr_family]
                        for entry in sorted(entries.keys()):
                            if entry.startswith(('pre','post','up','down')):
                                for cmd in entries[entry]:
                                    fd.write(
                                        '    %s %s' % (entry, cmd)
                                        + '\n'
                                    )
                            else:
                                fd.write(
                                    '    %s %s' % (entry, entries[entry])
                                    + '\n'
                                )
                        fd.write('\n')
                else:
                    ignored.append('Key error: %s' % directive)

        # Close file so we can move it
        fd.close()
        #os.rename('/etc/network/interfaces.tmp', '/etc/network/interfaces')

        module.exit_json(
            changed=changed,
            results=json.dumps(results),
            ignored=json.dumps(ignored)
        )
    except Exception, e:
        module.fail_json(
            msg='%s' % e,
            results=json.dumps(results),
            ignored=json.dumps(ignored)
        )

def main():
    module = AnsibleModule(
        argument_spec   = dict(
            state       = dict(required=False,
                               default='present',
                               choices=['present', 'absent']),
            name        = dict(required=True,
                               aliases=['interface']),
            auto        = dict(required=False,
                               default=True,
                               choices=BOOLEANS),
            hotplug     = dict(required=False,
                               default=False,
                               choices=BOOLEANS),
            iface_type  = dict(required=False,
                               default='dhcp',
                               choices=['dhcp', 'manual', 'static']),
            addr_family = dict(required=False,
                               default='inet',
                               choices=['inet', 'inet6']),
            address     = dict(required=False),
            netmask     = dict(required=False),
            nameservers = dict(required=False),
            gateway     = dict(required=False)
        )
    )

    state       = module.params.get('state')
    name        = module.params.get('name')
    auto        = module.params.get('auto')
    hotplug     = module.params.get('hotplug')
    iface_type  = module.params.get('iface_type')
    addr_family = module.params.get('addr_family')
    address     = module.params.get('address')
    netmask     = module.params.get('netmask')
    nameservers = module.params.get('nameservers')
    gateway     = module.params.get('gateway')

    update(module, state, name, auto, hotplug, iface_type, addr_family, address,
           netmask, nameservers, gateway)

# include magic from lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()