Wireguard prettifier

wgp.py

#!/usr/bin/python3

'''
The script looks for a line similar to:
PublicKey=eP5bTA845m1hTnp0bjgFnw4efn+NHQ7WrXVwVmffwhY=

Then it goes back one line and uses that if it is a comment
# Example comment

Example file content
```
[Peer]
# Example
PublicKey = eP5bTA845m1hTnp0bjgFnw4efn+NHQ7WrXVwVmffwhY=
AllowedIPs = 192.0.2.3/32, 2001:db8::3cf5/128
```
'''

import argparse
import os
import re
import subprocess

parser = argparse.ArgumentParser()
parser.add_argument('-c', '--cfg', default='/etc/systemd/network/wg0.netdev')
args = parser.parse_args()

pubkeyRegex = re.compile(r'^PublicKey ?= ?(.*)$', re.IGNORECASE)
peerRegex = re.compile(r'^peer: (.*)$')

keyLabels = {}

# Stores the previous line from the current iteration
prevLine = ''

with open(args.cfg) as f:
    for line in f:
        line = line.strip()

        pubkeyMatch = re.search(pubkeyRegex, line)

        if pubkeyMatch != None:
            pubkey = pubkeyMatch.group(1)

            # The regex can match empty string so we prevent that here
            if len(pubkey) != 44:
                continue

            # If the previous line was a comment, then use it
            if len(prevLine) > 3 and prevLine[0] == '#':
                keyLabels[pubkey] = prevLine[2:]
            else:
                keyLabels[pubkey] = 'Unknown'

        prevLine = line

# We have parsed the config file, now we will run wg and modify its output

wg = subprocess.run(['wg'], encoding='utf-8', stdout=subprocess.PIPE)

for line in wg.stdout.split('\n'):
    peerMatch = re.search(peerRegex, line)

    if peerMatch != None:
        pubkey = peerMatch.group(1)

        if pubkey in keyLabels.keys():
            print('{} is {}'.format(line.strip(), keyLabels[pubkey]))
            continue

    print(line)