Forming a list of dicts in a loop according to if conditions - python-3.x

Question

I need your help.
I have this code:
import ipaddress
from ipaddress import IPv4Network
prefixes = []
ip_addresses_all = [{'address': '10.0.0.1/24', 'vrf': {'id': 31,'name': 'god_inet'},
{'address': '10.0.0.10/24', 'vrf': {'id': 33, 'name': 'for_test'},
{'address': '10.1.1.1/30', 'vrf': {'id': 8, 'name': 'ott_private_net'},
{'address': '10.1.1.2/30', 'vrf': {'id': 11,'name': 'ott_public_net'},
{'address': '10.10.0.129/30', 'vrf': None,},
{'address': '10.10.0.130/30', 'vrf': None,},
{'address': '10.10.0.137/30', 'vrf': None,},
{'address': '10.10.0.138/30', 'vrf': None,}]
for ip in ip_addresses_all:
prefix = str(ipaddress.ip_network(ip.address, False))
mask_length = int(IPv4Network(prefix).prefixlen)
description_interface = ip.address
if ip.vrf:
ip_vrf_name = ip.vrf.name
ip_vrf_id = ip.vrf.id
ip_vrf = ip.vrf
else:
ip_vrf_name = 'null'
ip_vrf_id = 'null'
ip_vrf = 'null'
prefix_dict = {'prefix': prefix,
'vrf': {'name': ip_vrf_name,
'id': ip_vrf_id},
'prefix_description': [description_interface]}
if prefixes:
for i in prefixes:
if prefix != i['prefix']:
prefixes.append(prefix_dict)
elif i['prefix'] == prefix and i['vrf']['name'] == ip_vrf_name and description_interface not in i['prefix_description']:
i['prefix_description'].append(description_interface)
else:
prefixes.append(prefix_dict)
pprint(prefixes)
So, I wanna append the 'prefixes' list with dicts according to this logic : if prefix not in prefixes = [] - create new dict , if prefix with the same vrf already exists, then append a description string to a description key and update existing dict.
I struggle with this for 8 hours and it doesnt work, Ive got infinite loops=)
Intended output, something like that:
{'10.0.0.0/24': {'prefix_description': ['10.0.0.10/24'],'vrf': {'id': 31, 'name': 'god_inet'}},
'10.0.0.0/24': {'prefix_description': ['10.0.0.10/24'],'vrf': {'id': 33, 'name': 'for_test'}},
'10.1.1.0/30': {'prefix_description': ['10.1.1.2/30'],'vrf': {'id': 8, 'name': 'ott_private_net'}},
'10.1.1.0/30': {'prefix_description': ['10.1.1.2/30'],'vrf': {'id': 11, 'name': 'ott_public_net'}},
'10.10.0.128/30': {'prefix_description': ['10.10.0.129/30',
'10.10.0.130/30'],'vrf': {'id': 'null', 'name': 'null'}},
'10.10.0.136/30': {'prefix_description': ['10.10.0.137/30',
'10.10.0.138/30'],'vrf': {'id': 'null', 'name': 'null'}}}
Or better in a list like that:
[{'prefix': '10.0.0.0/24',
'prefix_description': ['77-GOD-VPN-2 ---- Vlan40'],
'vrf': {'id': 31, 'name': 'god_inet'}},
{'prefix': '10.0.0.0/24',
'prefix_description': ['78-ELS-CORE ---- Vlan142'],
'vrf': {'id': 33, 'name': 'for_test'}}]

Answer 1

make prefixes a dict and handle that code in the for loop
import ipaddress
from ipaddress import IPv4Network
prefixes = {}
ip_addresses_all = [{'address': '10.0.0.1/24', 'vrf': {'id': 31,'name': 'god_inet'}},
{'address': '10.0.0.10/24', 'vrf': {'id': 33, 'name': 'for_test'}},
{'address': '10.1.1.1/30', 'vrf': {'id': 8, 'name': 'ott_private_net'}},
{'address': '10.1.1.2/30', 'vrf': {'id': 11,'name': 'ott_public_net'}},
{'address': '10.10.0.129/30', 'vrf': None,},
{'address': '10.10.0.130/30', 'vrf': None,},
{'address': '10.10.0.137/30', 'vrf': None,},
{'address': '10.10.0.138/30', 'vrf': None,}]
for ip in ip_addresses_all:
prefix = str(ipaddress.ip_network(ip['address'], False))
mask_length = int(IPv4Network(prefix).prefixlen)
description_interface = ip['address']
if ip['vrf']:
ip_vrf_name = ip['vrf']['name']
ip_vrf_id = ip['vrf']['id']
ip_vrf = ip['vrf']
else:
ip_vrf_name = 'null'
ip_vrf_id = 'null'
ip_vrf = 'null'
prefix_dict = {
'vrf': {'name': ip_vrf_name,
'id': ip_vrf_id},
'prefix_description': [description_interface]}
if prefix in prefixes and \
prefixes[prefix]['vrf']['name'] == ip_vrf_name and \
description_interface not in prefixes[prefix]['prefix_description']:
prefixes[prefix]['prefix_description'].append(description_interface)
else:
prefixes[prefix] = prefix_dict
from pprint import pprint
pprint(prefixes)
output
{'10.0.0.0/24': {'prefix_description': ['10.0.0.10/24'],
'vrf': {'id': 33, 'name': 'for_test'}},
'10.1.1.0/30': {'prefix_description': ['10.1.1.2/30'],
'vrf': {'id': 11, 'name': 'ott_public_net'}},
'10.10.0.128/30': {'prefix_description': ['10.10.0.129/30', '10.10.0.130/30'],
'vrf': {'id': 'null', 'name': 'null'}},
'10.10.0.136/30': {'prefix_description': ['10.10.0.137/30', '10.10.0.138/30'],
'vrf': {'id': 'null', 'name': 'null'}}}