Files
BanGUI/backend/app/utils/runtime_state.py

226 lines
7.8 KiB
Python

"""Centralise mutable runtime application state.
Runtime state is kept outside of Starlette's raw ``app.state`` storage and
exposed through a controlled state manager object. This keeps the FastAPI
framework state bag limited to shared infrastructure handles and immutable
configuration while still allowing existing code to access runtime values via
attribute proxying.
"""
from __future__ import annotations
import datetime
from dataclasses import dataclass, field
from typing import TYPE_CHECKING, Any
from starlette.datastructures import State
import structlog
from app.models.config import PendingRecovery
from app.models.server import ServerStatus
if TYPE_CHECKING: # pragma: no cover
from app.config import Settings
log: structlog.stdlib.BoundLogger = structlog.get_logger()
ActivationRecord = dict[str, datetime.datetime]
# Maximum seconds since an activation for a subsequent crash to be
# attributed to that activation.
_ACTIVATION_CRASH_WINDOW: int = 60
_RUNTIME_ATTRIBUTES: frozenset[str] = frozenset(
{
"setup_complete_cached",
"server_status",
"pending_recovery",
"last_activation",
"runtime_settings",
}
)
@dataclass
class RuntimeState:
"""Mutable runtime state for the current application instance."""
setup_complete_cached: bool = False
server_status: ServerStatus = field(default_factory=lambda: ServerStatus(online=False))
pending_recovery: PendingRecovery | None = None
last_activation: ActivationRecord | None = None
runtime_settings: Settings | None = None
class ApplicationState(State):
"""Application state wrapper that delegates runtime state access.
This allows runtime values to be stored in a dedicated
:class:`RuntimeState` instance while preserving the familiar attribute-based
``app.state`` API for the rest of the application.
"""
def __init__(self, runtime_state: RuntimeState, state: dict[str, Any] | None = None):
super().__init__(state)
object.__setattr__(self, "_runtime_state", runtime_state)
@property
def runtime_state(self) -> RuntimeState:
"""Return the dedicated runtime state manager."""
return object.__getattribute__(self, "_runtime_state")
def __getattr__(self, key: str) -> Any:
if key in _RUNTIME_ATTRIBUTES:
return getattr(self.runtime_state, key)
return super().__getattr__(key)
def __setattr__(self, key: str, value: Any) -> None:
if key in _RUNTIME_ATTRIBUTES:
setattr(self.runtime_state, key, value)
return
super().__setattr__(key, value)
def __delattr__(self, key: str) -> None:
if key in _RUNTIME_ATTRIBUTES:
delattr(self.runtime_state, key)
return
super().__delattr__(key)
def get_runtime_state(app: Any) -> RuntimeState:
"""Return the runtime state manager for the current FastAPI application."""
state = getattr(app, "state", None)
if state is None or not hasattr(state, "runtime_state"):
raise AttributeError("Runtime state has not been initialised on the application.")
return state.runtime_state
def get_app_settings(app: Any) -> Settings:
"""Return the bootstrap settings loaded at startup."""
settings = getattr(app.state, "settings", None)
if settings is None:
raise AttributeError("Application settings are not available on the app state.")
return settings
def get_effective_settings(app: Any) -> Settings:
"""Return the effective settings for the current application instance."""
runtime_settings = getattr(app.state, "runtime_settings", None)
if runtime_settings is not None:
return runtime_settings
return get_app_settings(app)
def set_runtime_settings(app: Any, settings: Settings) -> None:
"""Store the resolved runtime settings separately from bootstrap config."""
runtime_state = get_runtime_state(app)
runtime_state.runtime_settings = settings
def update_app_settings(app: Any, **overrides: Any) -> None:
"""Update the current effective settings immutably."""
settings = get_app_settings(app)
updated = settings.model_copy(update=overrides)
set_runtime_settings(app, updated)
def record_activation(app: Any, jail_name: str, at: datetime.datetime | None = None) -> datetime.datetime:
"""Record a jail activation timestamp in runtime state."""
now = at if at is not None else datetime.datetime.now(tz=datetime.UTC)
runtime_state = get_runtime_state(app)
runtime_state.last_activation = {
"jail_name": jail_name,
"at": now,
}
return now
def create_pending_recovery(
app: Any,
jail_name: str,
activated_at: datetime.datetime,
detected_at: datetime.datetime | None = None,
) -> None:
"""Create a pending recovery record in runtime state."""
runtime_state = get_runtime_state(app)
runtime_state.pending_recovery = PendingRecovery(
jail_name=jail_name,
activated_at=activated_at,
detected_at=detected_at if detected_at is not None else datetime.datetime.now(tz=datetime.UTC),
)
def clear_pending_recovery(app: Any) -> None:
"""Clear the current pending recovery record."""
get_runtime_state(app).pending_recovery = None
def clear_activation_record(app: Any) -> None:
"""Clear the current activation tracking record."""
get_runtime_state(app).last_activation = None
def process_health_probe_result(
runtime_state: RuntimeState,
status: ServerStatus,
now: datetime.datetime | None = None,
) -> None:
"""Process a new health probe result and update runtime state.
This function tracks fail2ban transitions and creates or resolves
pending recovery records when the daemon goes offline shortly after a
jail activation.
Args:
runtime_state: The mutable runtime state manager.
status: The latest fail2ban server status.
now: The current timestamp used for time-based decisions.
"""
prev_status = getattr(runtime_state, "server_status", ServerStatus(online=False))
runtime_state.server_status = status
now = now if now is not None else datetime.datetime.now(tz=datetime.UTC)
if status.online and not prev_status.online:
log.info("fail2ban_came_online", version=status.version)
existing = runtime_state.pending_recovery
if existing is not None and not existing.recovered:
runtime_state.pending_recovery = PendingRecovery(
jail_name=existing.jail_name,
activated_at=existing.activated_at,
detected_at=existing.detected_at,
recovered=True,
)
log.info(
"pending_recovery_resolved",
jail=existing.jail_name,
)
elif not status.online and prev_status.online:
log.warning("fail2ban_went_offline")
last_activation = runtime_state.last_activation
if last_activation is not None:
activated_at = last_activation["at"]
seconds_since = (now - activated_at).total_seconds()
if seconds_since <= _ACTIVATION_CRASH_WINDOW:
jail_name = last_activation["jail_name"]
current = runtime_state.pending_recovery
if current is None or current.recovered:
runtime_state.pending_recovery = PendingRecovery(
jail_name=jail_name,
activated_at=activated_at,
detected_at=now,
)
log.warning(
"activation_crash_detected",
jail=jail_name,
seconds_since_activation=seconds_since,
)
log.debug(
"health_check_complete",
online=status.online,
version=status.version,
active_jails=status.active_jails,
)