Reads Packet.net metadata JSON and writes out RedHat style /etc/sysconfig/network-scripts config

packet-configure-network.py

#!/usr/bin/env python3

import argparse
import glob
import ipaddress
import json
import os
import requests

PACKET_BOND_OPTIONS = 'miimon=100 downdelay=200 updelay=200 xmit_hash_policy=1 lacp_rate=1'
PACKET_DNS = [
    '147.75.207.207',
    '147.75.207.208'
]
PACKET_V4_PRIVATE_NETWORK = '10.0.0.0/8'

def get_metadata(args):
    if args.file:
        with open(args.file, 'r') as json_file:
            metadata = json.load(json_file)
    else:
        r = requests.get(args.url)
        r.raise_for_status()
        metadata = r.json()

    return metadata

def write_files(args, ifcfgs, routes):
    for iface,ifcfg in ifcfgs.items():
        fn = 'ifcfg-{}'.format(iface)
        if args.debug:
            for k in sorted(ifcfg):
                print('{}: {}={}'.format(fn, k, ifcfg[k]))
        else:
            with open(os.path.join(args.outdir, fn), 'w') as iface_file:
                for k in sorted(ifcfg):
                    iface_file.write('{}={}\n'.format(k, ifcfg[k]))

    for iface,route in routes.items():
        fn = 'route-{}'.format(iface)
        if args.debug:
            for k in sorted(route):
                print('{}: {} via {}'.format(fn, k, route[k]))
        else:
            with open(os.path.join(args.outdir, fn), 'w') as route_file:
                for k in sorted(route):
                    route_file.write('{} via {}\n'.format(k, route[k]))

def get_iface_macs():
    devs = {}

    for iface in glob.glob('/sys/class/net/*'):
        # skip virtual interfaces
        device = os.path.join(iface, 'device')
        if not os.path.exists(device):
            continue
        with open(os.path.join(iface, 'address')) as mac_file:
            mac = mac_file.read().strip().lower()
            dev = os.path.basename(iface)
            devs[mac] = dev

    return devs

def add_bond(ifcfgs, bond, bond_mode):
    assert (bond not in ifcfgs)
    bond_opts = '"mode={} {}"'.format(bond_mode, PACKET_BOND_OPTIONS)
    cfg = {
        'DEVICE': bond,
        'NAME': bond,
        'BOOTPROTO': 'none',
        'ONBOOT': 'yes',
        'USERCTL': 'no',
        'TYPE': 'Bond',
        'BONDING_OPTS': bond_opts
    }
    ifcfgs[bond] = cfg

def add_alias(ifcfgs, alias):
    assert (alias not in ifcfgs)
    cfg = {
        'DEVICE': alias,
        'NAME': alias,
        'ONBOOT': 'yes',
        'USERCTL': 'no'
    }
    ifcfgs[alias] = cfg

def add_route(routes, iface, network, gateway):
    route = routes.setdefault(iface, {})
    new_route = {
        network: gateway
    }
    route.update(new_route)

def add_interface(ifcfgs, name, mac, bond):
    assert (name not in ifcfgs)
    cfg = {
        'DEVICE': name,
        'ONBOOT': 'yes',
        'HWADDR': mac,
        'MASTER': bond,
        'SLAVE': 'yes',
        'BOOTPROTO': 'none',
    }
    ifcfgs[name] = cfg

def add_interfaces(ifcfgs, interfaces):
    iface_macs = get_iface_macs()

    for iface in interfaces:
        name = iface['name']
        mac = iface['mac']
        bond = iface['bond']

        assert (bond in ifcfgs)

        if mac in iface_macs:
            name = iface_macs[mac]

        add_interface(ifcfgs, name, mac, bond)

def incr_alias(iface):
    if ':' not in iface:
        return iface + ':0'

    a,b = iface.rsplit(':', 1)
    b = b+1
    return iface + ':' + b

def find_free_alias(ifcfgs, iface, key):
    while key in ifcfgs[iface]:
        iface = incr_alias(iface)
        if iface not in ifcfgs:
            add_alias(ifcfgs, iface)

    return iface
            
def add_v4_address(ifcfgs, iface, addr):
    iface = find_free_alias(ifcfgs, iface, 'IPADDR')
    cfg = {
        'IPADDR': addr['address'],
        'NETMASK': addr['netmask'],
    }
    if addr['public']:
        cfg['GATEWAY'] = addr['gateway']
    ifcfgs[iface].update(cfg)

def add_v6_address(ifcfgs, iface, addr):
    iface = find_free_alias(ifcfgs, iface, 'IPV6ADDR')
    cfg = {
        'IPV6INIT': 'yes',
        'IPV6ADDR': '{}/{}'.format(addr['address'], addr['cidr']),
    }
    if addr['public']:
        cfg['IPV6_DEFAULTGW'] = addr['gateway']
    ifcfgs[iface].update(cfg)

def add_addresses(ifcfgs, routes, iface, addresses):
    for addr in addresses:
        if not addr['enabled']:
            continue

        if addr['address_family'] == 4:
            add_v4_address(ifcfgs, iface, addr)
            if not addr['public']:
                add_route(routes, iface, PACKET_V4_PRIVATE_NETWORK, addr['gateway'])
        elif addr['address_family'] == 6:
            add_v6_address(ifcfgs, iface, addr)
        else:
            raise Exception('unexpected address family')

def add_dns(ifcfgs, iface, servers):
    i = 1
    for server in servers:
        ifcfgs[iface]['DNS{}'.format(i)] = server
        i = i+1
    ifcfgs[iface]['PEERDNS'] = 'yes'
        cfg['IPV6_DEFAULTGW'] = addr['gateway']
    ifcfgs[iface].update(cfg)

def add_addresses(ifcfgs, routes, iface, addresses):
    for addr in addresses:
        if not addr['enabled']:
            continue

        if addr['address_family'] == 4:
            add_v4_address(ifcfgs, iface, addr)
            if not addr['public']:
                add_route(routes, iface, PACKET_V4_PRIVATE_NETWORK, addr['gateway'])
        elif addr['address_family'] == 6:
            add_v6_address(ifcfgs, iface, addr)
        else:
            raise Exception('unexpected address family')

def add_dns(ifcfgs, iface, servers):
    i = 1
    for server in servers:
        ifcfgs[iface]['DNS{}'.format(i)] = server
        i = i+1
    ifcfgs[iface]['PEERDNS'] = 'yes'

def main(args):
    metadata = get_metadata(args)
    network = metadata['network']

    if 'bonding' not in network:
        raise Exception('not a bonded network, don\'t know how to proceed')

    ifcfgs = {}
    routes = {}

    bond = 'bond0'
    bond_mode = network['bonding']['mode']
    add_bond(ifcfgs, 'bond0', bond_mode)

    interfaces = network['interfaces']
    add_interfaces(ifcfgs, interfaces)

    addresses = network['addresses']
    add_addresses(ifcfgs, routes, bond, addresses)

    add_dns(ifcfgs, bond, PACKET_DNS)

    write_files(args, ifcfgs, routes)

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Fetch Packet.net metadata and write out ifcfg and route files for RH-style network config')
    parser.add_argument('-d', '--debug', action='store_true', help='Write to stdout instead of files')
    parser.add_argument('-o', '--outdir', default='/etc/sysconfig/network-scripts', help='Folder to write ifcfg-*/route-* files to')
    group = parser.add_mutually_exclusive_group()
    group.add_argument('-f', '--file', help='Use local input file instead of remote fetch')
    group.add_argument('-u', '--url', default='https://metadata.packet.net/metadata', help='Remote metadata URL to fetch')

    args = parser.parse_args()

    main(args)