Files
BanGUI/backend/app/services/health_service.py

172 lines
6.3 KiB
Python

"""Health service.
Probes the fail2ban socket to determine whether the daemon is reachable and
collects aggregated server statistics (version, jail count, ban counts).
The probe is intentionally lightweight — it is meant to be called every 30
seconds by the background health-check task, not on every HTTP request.
"""
from __future__ import annotations
from typing import Any
import structlog
from app.models.server import ServerStatus
from app.utils.fail2ban_client import Fail2BanClient, Fail2BanConnectionError, Fail2BanProtocolError
log: structlog.stdlib.BoundLogger = structlog.get_logger()
# ---------------------------------------------------------------------------
# Internal helpers
# ---------------------------------------------------------------------------
_SOCKET_TIMEOUT: float = 5.0
def _ok(response: Any) -> Any:
"""Extract the payload from a fail2ban ``(return_code, data)`` response.
fail2ban wraps every response in a ``(0, data)`` success tuple or
a ``(1, exception)`` error tuple. This helper returns ``data`` for
successful responses or raises :class:`ValueError` for error responses.
Args:
response: Raw value returned by :meth:`~Fail2BanClient.send`.
Returns:
The payload ``data`` portion of the response.
Raises:
ValueError: If the response indicates an error (return code ≠ 0).
"""
try:
code, data = response
except (TypeError, ValueError) as exc:
raise ValueError(f"Unexpected fail2ban response shape: {response!r}") from exc
if code != 0:
raise ValueError(f"fail2ban returned error code {code}: {data!r}")
return data
def _to_dict(pairs: Any) -> dict[str, Any]:
"""Convert a list of ``(key, value)`` pairs to a plain dict.
fail2ban returns structured data as lists of 2-tuples rather than dicts.
This helper converts them safely, ignoring non-pair items.
Args:
pairs: A list of ``(key, value)`` pairs (or any iterable thereof).
Returns:
A :class:`dict` with the keys and values from *pairs*.
"""
if not isinstance(pairs, (list, tuple)):
return {}
result: dict[str, Any] = {}
for item in pairs:
try:
k, v = item
result[str(k)] = v
except (TypeError, ValueError):
pass
return result
# ---------------------------------------------------------------------------
# Public interface
# ---------------------------------------------------------------------------
async def probe(socket_path: str, timeout: float = _SOCKET_TIMEOUT) -> ServerStatus:
"""Probe the fail2ban daemon and return a :class:`~app.models.server.ServerStatus`.
Sends ``ping``, ``version``, ``status``, and per-jail ``status <jail>``
commands. Any socket or protocol error is caught and results in an
``online=False`` status so the dashboard can always return a safe default.
Args:
socket_path: Path to the fail2ban Unix domain socket.
timeout: Per-command socket timeout in seconds.
Returns:
A :class:`~app.models.server.ServerStatus` snapshot. ``online`` is
``True`` when the daemon is reachable, ``False`` otherwise.
"""
client = Fail2BanClient(socket_path=socket_path, timeout=timeout)
try:
# ------------------------------------------------------------------ #
# 1. Connectivity check #
# ------------------------------------------------------------------ #
ping_data = _ok(await client.send(["ping"]))
if ping_data != "pong":
log.warning("fail2ban_unexpected_ping_response", response=ping_data)
return ServerStatus(online=False)
# ------------------------------------------------------------------ #
# 2. Version #
# ------------------------------------------------------------------ #
try:
version: str | None = str(_ok(await client.send(["version"])))
except (ValueError, TypeError):
version = None
# ------------------------------------------------------------------ #
# 3. Global status — jail count and names #
# ------------------------------------------------------------------ #
status_data = _to_dict(_ok(await client.send(["status"])))
active_jails: int = int(status_data.get("Number of jail", 0) or 0)
jail_list_raw: str = str(status_data.get("Jail list", "") or "").strip()
jail_names: list[str] = (
[j.strip() for j in jail_list_raw.split(",") if j.strip()]
if jail_list_raw
else []
)
# ------------------------------------------------------------------ #
# 4. Per-jail aggregation #
# ------------------------------------------------------------------ #
total_bans: int = 0
total_failures: int = 0
for jail_name in jail_names:
try:
jail_resp = _to_dict(_ok(await client.send(["status", jail_name])))
filter_stats = _to_dict(jail_resp.get("Filter") or [])
action_stats = _to_dict(jail_resp.get("Actions") or [])
total_failures += int(filter_stats.get("Currently failed", 0) or 0)
total_bans += int(action_stats.get("Currently banned", 0) or 0)
except (ValueError, TypeError, KeyError) as exc:
log.warning(
"fail2ban_jail_status_parse_error",
jail=jail_name,
error=str(exc),
)
log.debug(
"fail2ban_probe_ok",
version=version,
active_jails=active_jails,
total_bans=total_bans,
total_failures=total_failures,
)
return ServerStatus(
online=True,
version=version,
active_jails=active_jails,
total_bans=total_bans,
total_failures=total_failures,
)
except (Fail2BanConnectionError, Fail2BanProtocolError) as exc:
log.warning("fail2ban_probe_failed", error=str(exc))
return ServerStatus(online=False)
except ValueError as exc:
log.error("fail2ban_probe_parse_error", error=str(exc))
return ServerStatus(online=False)