bundlewrap/bundles/left4me/metadata.py

assert node.has_bundle('nftables'), (
    f'{node.name}: bundle left4me requires bundle nftables (uses nftables/output for srcds DSCP marking)'
)
assert node.has_bundle('systemd'), (
    f'{node.name}: bundle left4me requires bundle systemd (declares units via systemd/units metadata)'
)


defaults = {
    'left4me': {
        # Application-wide defaults; node only overrides if it really needs to.
        'git_url': 'git@git.sublimity.de:cronekorkn/left4me',
        'git_branch': 'master',
        'secret_key': repo.vault.random_bytes_as_base64_for(f'{node.name} left4me secret_key', length=32).value,
        'gunicorn_workers': 1,
        'gunicorn_threads': 32,
        'job_worker_threads': 4,
        'port_range_start': 27015,
        'port_range_end': 27115,
    },
    'apt': {
        'packages': {
            'p7zip-full': {},
            'nftables': {},
            'iproute2': {},
            'curl': {},
            'ca-certificates': {},
            'python3': {},
            'python3-venv': {},
            'python3-pip': {},
            'python3-dev': {},
        },
    },
    'nftables': {
        # Match deploy/files/usr/local/lib/left4me/nft/left4me-mark.nft.
        # Mark srcds UDP egress (uid left4me) with DSCP EF + skb priority 6
        # so CAKE classifies it into the priority tin.
        'output': {
            'meta skuid "left4me" meta l4proto udp ip dscp set ef meta priority set 0006:0000',
            'meta skuid "left4me" meta l4proto udp ip6 dscp set ef meta priority set 0006:0000',
        },
    },
    'systemd': {
        'services': {
            'left4me-web.service': {
                'enabled': True,
                'running': True,
                'needs': [
                    'action:left4me_alembic_upgrade',
                    'file:/etc/left4me/host.env',
                    'file:/etc/left4me/web.env',
                ],
            },
            # Note: left4me-server@.service is a TEMPLATE — instances are
            # started on-demand by the web app via the left4me-systemctl
            # helper. Don't enable/start it from here.
            # The slices are installed (file present) but don't need
            # enable/start — they're activated implicitly when a unit
            # uses Slice=.
        },
    },
    'backup': {
        # Application-owned paths. Set-merged with backup group / node-level paths.
        'paths': {
            '/var/lib/left4me',
            '/etc/left4me',
        },
    },
}


@metadata_reactor.provides(
    'nginx/vhosts',
    'nftables/input',
)
def derived_from_domain(metadata):
    # letsencrypt/domains is auto-populated from nginx/vhosts.keys() by
    # bundles/nginx/metadata.py. monitoring/services for the vhost is also
    # auto-populated there using the vhost's check_path/check_protocol —
    # we just declare check_path: '/health' below to point the auto-check
    # at the Flask health endpoint instead of '/'.
    domain = metadata.get('left4me/domain')
    port_start = metadata.get('left4me/port_range_start')
    port_end = metadata.get('left4me/port_range_end')

    return {
        'nginx': {
            'vhosts': {
                domain: {
                    'content': 'nginx/proxy_pass.conf',
                    'context': {
                        'target': 'http://127.0.0.1:8000',
                    },
                    'check_path': '/health',
                },
            },
        },
        'nftables': {
            'input': {
                f'udp dport {port_start}-{port_end} accept',
                f'tcp dport {port_start}-{port_end} accept',
            },
        },
    }


@metadata_reactor.provides(
    'systemd/units',
)
def systemd_units(metadata):
    workers = metadata.get('left4me/gunicorn_workers')
    threads = metadata.get('left4me/gunicorn_threads')

    web_service = {
        'Unit': {
            'Description': 'left4me web application',
            'After': 'network-online.target',
            'Wants': 'network-online.target',
        },
        'Service': {
            'Type': 'simple',
            'User': 'left4me',
            'Group': 'left4me',
            'WorkingDirectory': '/opt/left4me/src',
            'Environment': {
                'HOME=/var/lib/left4me',
                'PATH=/opt/left4me/.venv/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin',
            },
            'EnvironmentFile': (
                '/etc/left4me/host.env',
                '/etc/left4me/web.env',
            ),
            'ExecStart': (
                '/opt/left4me/.venv/bin/gunicorn '
                f'--workers {workers} --threads {threads} '
                "--bind 127.0.0.1:8000 'l4d2web.app:create_app()'"
            ),
            'Restart': 'on-failure',
            'RestartSec': '3',
            # NoNewPrivileges intentionally NOT set: workers sudo to the helpers.
            'ProtectSystem': 'full',
            'ReadWritePaths': '/var/lib/left4me',
            'PrivateTmp': 'true',
        },
        'Install': {
            'WantedBy': {'multi-user.target'},
        },
    }

    server_template = {
        'Unit': {
            'Description': 'left4me server instance %i',
            'After': 'network-online.target',
            'Wants': 'network-online.target',
            'StartLimitBurst': '5',
            'StartLimitIntervalSec': '60s',
        },
        'Service': {
            'Type': 'simple',
            'User': 'left4me',
            'Group': 'left4me',
            'EnvironmentFile': (
                '/etc/left4me/host.env',
                '/var/lib/left4me/instances/%i/instance.env',
            ),
            'WorkingDirectory': '-/var/lib/left4me/runtime/%i/merged/left4dead2',
            'ExecStartPre': (
                '+/usr/bin/nsenter --mount=/proc/1/ns/mnt -- '
                '/usr/local/libexec/left4me/left4me-overlay mount %i'
            ),
            'ExecStart': (
                '/var/lib/left4me/runtime/%i/merged/srcds_run '
                '-game left4dead2 +hostport ${L4D2_PORT} $L4D2_ARGS'
            ),
            'ExecStopPost': (
                '+/usr/bin/nsenter --mount=/proc/1/ns/mnt -- '
                '/usr/local/libexec/left4me/left4me-overlay umount %i'
            ),
            'Restart': 'on-failure',
            'RestartSec': '5',
            'Slice': 'l4d2-game.slice',
            'Nice': '-5',
            'IOSchedulingClass': 'best-effort',
            'IOSchedulingPriority': '4',
            'OOMScoreAdjust': '-200',
            'MemoryHigh': '1.5G',
            'MemoryMax': '2G',
            'TasksMax': '256',
            'LimitNOFILE': '65536',
            'KillSignal': 'SIGINT',
            'TimeoutStopSec': '15s',
            'LogRateLimitIntervalSec': '0',
            'NoNewPrivileges': 'true',
            'PrivateTmp': 'true',
            'PrivateDevices': 'true',
            'ProtectHome': 'true',
            'ProtectSystem': 'strict',
            'ReadOnlyPaths': '/var/lib/left4me/installation /var/lib/left4me/overlays',
            'ReadWritePaths': '/var/lib/left4me/runtime/%i',
            'RestrictSUIDSGID': 'true',
            'LockPersonality': 'true',
        },
        'Install': {
            'WantedBy': {'multi-user.target'},
        },
    }

    game_slice = {
        'Unit': {
            'Description': 'left4me game-server slice',
            'Before': 'slices.target',
        },
        'Slice': {
            'CPUWeight': '1000',
            'IOWeight': '1000',
        },
    }

    build_slice = {
        'Unit': {
            'Description': 'left4me script-sandbox build slice',
            'Before': 'slices.target',
        },
        'Slice': {
            'CPUWeight': '10',
            'IOWeight': '10',
        },
    }

    return {
        'systemd': {
            'units': {
                'left4me-web.service':       web_service,
                'left4me-server@.service':   server_template,
                'l4d2-game.slice':           game_slice,
                'l4d2-build.slice':          build_slice,
            },
        },
    }