Timotej Lazar
048195c45c
Before we relied on the combined data being present in ipsets.json when generating a new config, but ipsets.json is only updated through the form at /ipsets. So submitting any other form after changing NetBox definitions might crash when trying to find an entry from networks.json in ipsets.json. Now we introduce a helper functon to always read both files and combine the prefixes fron networks.json with ipsets.json. This way it is not necessary to save a new ipsets.json before other changes. Also don’t crash when enumerating networks for each VPN group.
240 lines
11 KiB
Python
240 lines
11 KiB
Python
#!/usr/bin/python3
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import collections
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import email.message
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import getpass
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import multiprocessing
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import os
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import pathlib
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import shutil
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import smtplib
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import socket
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import subprocess
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import syslog
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import click
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import flask
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import flask.cli
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import ldap3
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from . import db
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from . import ipsets
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def init_app(app):
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app.cli.add_command(generate)
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app.cli.add_command(push)
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def mail(rcpt, subject, body):
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try:
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msg = email.message.EmailMessage()
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msg['Subject'] = f'friwall: {subject}'
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msg['From'] = f'{getpass.getuser()}@{socket.getfqdn()}'
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msg['To'] = rcpt
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msg.set_content(body)
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with smtplib.SMTP('localhost') as server:
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server.send_message(msg)
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except Exception as e:
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syslog.syslog(f'error sending mail: {e}')
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def run(fun, args=()):
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def task():
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if os.fork() == 0:
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os.setsid()
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fun(*args)
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multiprocessing.Process(target=task).start()
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# Generate configuration files and create a config tarball.
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def save_config():
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output = None
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try:
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# Just load required settings here but keep the database unlocked
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# while we load group memberships from LDAP.
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with db.locked():
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settings = db.read('settings')
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# Build LDAP query for users and groups.
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filters = [
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'(objectClass=user)', # only users
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'(objectCategory=person)', # that are people
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'(!(userAccountControl:1.2.840.113556.1.4.803:=2))', # with enabled accounts
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]
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if group := settings.get('user_group'):
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filters += [f'(memberOf:1.2.840.113556.1.4.1941:={group})'] # in given group, recursively
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# Run query and store group membership data.
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server = ldap3.Server(settings['ldap_host'], use_ssl=True)
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ldap = ldap3.Connection(server, settings['ldap_user'], settings['ldap_pass'], auto_bind=True)
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ldap.search(settings.get('ldap_base_dn', ''),
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f'(&{"".join(filters)})', # conjuction (&(…)(…)(…)) of queries
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attributes=['userPrincipalName', 'memberOf'])
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user_groups = { e.userPrincipalName.value: set(e.memberOf) for e in ldap.entries }
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# Now read the settings again while keeping the database locked until
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# config files are generated, and increment version before unlocking.
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with db.locked():
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sets = ipsets.read()
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wireguard = db.read('wireguard')
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settings = db.read('settings')
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version = settings['version'] = int(settings.get('version') or '0') + 1
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# Find networks accessible to VPN users for each AD group.
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vpn_groups = {e['vpn'] for e in sets.values() if e.get('vpn')}
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group_networks = {
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group: [name for name, data in sets.items() if data.get('vpn') == group] for group in vpn_groups
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}
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# Add VPN addresses to IP sets.
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for ip, key in wireguard.items():
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# Find all networks this IP should belong to:
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# - manually specified networks for custom keys,
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# - networks accessible to any of the user’s groups.
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key_networks = set(key.get('networks', ()))
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for group in user_groups.get(key.get('user', ''), ()):
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key_networks |= set(group_networks.get(group, ()))
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for network in key_networks:
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sets[network]['ip'].append(f'{ip}/32')
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if ip6 := key.get('ip6'):
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sets[network]['ip6'].append(ip6)
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# Create config files.
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output = pathlib.Path.home() / 'config' / f'{version}'
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shutil.rmtree(output, ignore_errors=True)
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os.makedirs(output / 'etc/nftables.d', exist_ok=True)
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os.makedirs(output / 'etc/wireguard', exist_ok=True)
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# Print version.
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with open(output / 'version', 'w', encoding='utf-8') as f:
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f.write(f'{version}')
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# Print nftables sets.
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with open(output / 'etc/nftables.d/sets.nft', 'w', encoding='utf-8') as f:
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nft_set = 'set {name} {{\n type ipv4_addr; flags interval; {ips}\n}}\n'
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nft_set6 = 'set {name}/6 {{\n type ipv6_addr; flags interval; {ips}\n}}\n'
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def make_set(ips):
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# return "elements = { ip1, ip2, … }", prefixed with "# " if no ips
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return f'{"" if ips else "# "}elements = {{ {", ".join(ips)} }}'
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for name, data in sets.items():
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f.write(nft_set.format(name=name, ips=make_set(data.get('ip', ()))))
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f.write(nft_set6.format(name=name, ips=make_set(data.get('ip6', ()))))
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f.write('\n')
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# Print static NAT (1:1) rules.
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with open(output / 'etc/nftables.d/netmap.nft', 'w', encoding='utf-8') as f:
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nft_map = 'map {name} {{\n type ipv4_addr : interval ipv4_addr; flags interval; elements = {{\n{ips}\n }}\n}}\n'
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def make_map(ips, reverse=False):
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# return "{ from1: to1, from2: to2, … }" with possibly reversed from and to
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return ',\n'.join(f"{b if reverse else a}: {a if reverse else b}" for a, b in ips)
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if netmap := db.read('netmap'): # { private range: public range… }
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f.write(nft_map.format(name='netmap-out', ips=make_map(netmap.items())))
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f.write('\n')
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f.write(nft_map.format(name='netmap-in', ips=make_map(netmap.items(), reverse=True)))
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# Print dynamic NAT rules.
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with open(output / 'etc/nftables.d/nat.nft', 'w', encoding='utf-8') as f:
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nft_nat = 'iif @inside oif @outside ip saddr @{name} snat to {nat}\n'
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for name, data in sets.items():
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if nat := data.get('nat'):
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f.write(nft_nat.format(name=name, nat=nat))
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# Print forwarding rules.
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with open(output / 'etc/nftables.d/forward.nft', 'w', encoding='utf-8') as f:
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# Forwarding rules for VPN users.
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if vpn_networks := sorted(name for name, data in sets.items() if data.get('vpn')):
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nft_forward = 'iif @inside oif @inside ip saddr @{name} ip daddr @{name} accept\n'
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nft_forward6 = 'iif @inside oif @inside ip6 saddr @{name}/6 ip6 daddr @{name}/6 accept\n'
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f.write('# forward from the VPN interface to physical networks and back\n')
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for name in vpn_networks:
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f.write(nft_forward.format(name=name))
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for name in vpn_networks:
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f.write(nft_forward6.format(name=name))
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f.write('\n')
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# Custom forwarding rules.
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nft_rule = '# {index}. {name}\n{text}\n\n'
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for index, rule in enumerate(db.read('rules')):
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if rule.get('enabled') and rule.get('text'):
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f.write(nft_rule.format(index=index, name=rule.get('name', ''), text=rule['text']))
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# Print wireguard config.
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with open(output / 'etc/wireguard/wg.conf', 'w', encoding='utf-8') as f:
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# Server configuration.
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wg_intf = '[Interface]\nListenPort = {port}\nPrivateKey = {key}\n\n'
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f.write(wg_intf.format(port=settings.get('wg_port') or 51820, key=settings.get('wg_key')))
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# Client configuration.
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wg_peer = '# {user}\n[Peer]\nPublicKey = {key}\nAllowedIPs = {ips}\n\n'
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for ip, data in wireguard.items():
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f.write(wg_peer.format(
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user=data.get('user'),
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key=data.get('key'),
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ips=', '.join(filter(None, [ip, data.get('ip6')]))))
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# Make a temporary config archive and move it to the final location,
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# so we avoid sending incomplete tars.
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tar_file = shutil.make_archive(f'{output}-tmp', 'gztar', root_dir=output, owner='root', group='root')
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os.rename(tar_file, f'{output}.tar.gz')
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# If we get here, write settings with the new version.
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db.write('settings', settings)
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return True
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except Exception as e:
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import traceback
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e.add_note(f'exception while generating config: {e}')
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msg = traceback.format_exc()
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if rcpt := settings.get('admin_mail'):
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mail(rcpt, 'error generating config', msg)
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# TODO this doesn’t seem to work
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#syslog.syslog(msg)
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return False
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finally:
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# Remove temporary directory.
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if output:
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shutil.rmtree(output, ignore_errors=True)
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@click.command('generate')
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@flask.cli.with_appcontext
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def generate():
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save_config()
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@click.command('push')
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@click.option('--version', '-v', type=click.INT, default=None, help="Config version to push")
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@flask.cli.with_appcontext
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def push(version=None):
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try:
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with db.locked('nodes'):
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if version is None:
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version = db.load('settings').get('version', 0)
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nodes = db.read('nodes')
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tar_file = pathlib.Path.home() / 'config' / f'{version}.tar.gz'
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errors = []
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for node, node_version in nodes.items():
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if node_version != version:
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try:
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# Push config tarfile to node. There sshd runs a forced command that
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# reads in a tarball, copies files to /etc and reloads services.
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syslog.syslog(f'updating config for {node} from v{node_version} to v{version}')
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result = subprocess.run(['/usr/bin/ssh', '-T', '-o', 'ConnectTimeout=10', f'root@{node}'],
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stdin=open(tar_file), capture_output=True, text=True)
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if result.returncode == 0:
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nodes[node] = version
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db.write('nodes', nodes)
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syslog.syslog(f'successfully updated config for {node} to v{version}')
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else:
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raise RuntimeError(f'error updating config to v{version}: {result.stderr}')
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except (FileNotFoundError, RuntimeError) as e:
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e.add_note(f'error while updating node {node}')
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errors.append(e)
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if errors:
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raise ExceptionGroup('errors while updating nodes', errors)
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except Exception as e:
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import traceback
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msg = traceback.format_exc()
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if rcpt := db.load('settings').get('admin_mail'):
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mail(rcpt, 'error updating nodes', msg)
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syslog.syslog(msg)
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