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FabledSteward/steward/core/alerts.py
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bvandeusenandClaude Opus 5.5 a6c24299a2
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fix(alerts): acknowledgements hold until resolve; clear after N OK; rule changes reset (#5059)
#5059 "Alert state machine: acknowledgement holds until resolve; N
consecutive OK to resolve; editing, disabling or deleting a rule resets it".

- The state machine is now next_step(), a pure function of one sample. An
  acknowledged alert stays acknowledged while breached; before, the next
  breaching sample re-fired it. Firing and acknowledged alerts resolve after
  consecutive_ok_required OK checks in a row (new rule column, default 1;
  rule form, rules list and MCP create/update_alert_rule clear_after_checks).
- Changing what a rule watches (source, resource, metric, operator,
  threshold) or disabling it resets its alert to inactive; a firing or
  acknowledged one records a resolved event whose new note says why, and
  nobody is notified. Web and MCP edits share alerts.service.apply_rule_change.
- Migration 0028: consecutive_ok_required, consecutive_ok_count,
  alert_events.note, and metric_value nullable (a reset has no sample).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-06 11:32:17 -04:00

371 lines
13 KiB
Python

from __future__ import annotations
import asyncio
import logging
import uuid
from dataclasses import dataclass
from datetime import datetime, timezone
from typing import TYPE_CHECKING
from sqlalchemy import and_, or_, select
from sqlalchemy.ext.asyncio import AsyncSession
from steward.models.alerts import (
AlertEvent,
AlertOperator,
AlertRule,
AlertState,
AlertStateEnum,
MaintenanceWindow,
)
from steward.models.metrics import PluginMetric
if TYPE_CHECKING:
from quart import Quart
logger = logging.getLogger(__name__)
_app: "Quart | None" = None
def init_alerts(app: "Quart") -> None:
"""Store app reference for use in notification dispatch tasks."""
global _app
_app = app
def alert_extra_vars(rule: AlertRule, value: float) -> list[str]:
"""Ansible extra-vars describing the alert that fired, as `key=value` strings.
Injected into every alert-triggered playbook run so the playbook can target
the exact resource/metric that fired without templating. Pure function.
"""
return [
f"steward_alert_rule={rule.name}",
f"steward_alert_source={rule.source_module}",
f"steward_alert_resource={rule.resource_name}",
f"steward_alert_metric={rule.metric_name}",
f"steward_alert_value={value}",
f"steward_alert_threshold={rule.threshold}",
f"steward_alert_operator={rule.operator.value}",
]
async def record_metric(
session: AsyncSession,
source_module: str,
resource_name: str,
metric_name: str,
value: float,
) -> None:
"""Write a metric row and evaluate alert rules inline.
Must be called inside an active transaction:
async with session.begin():
await record_metric(session, ...)
Notification I/O is deferred via asyncio.create_task() so no network
calls occur while the transaction is open.
"""
now = datetime.now(timezone.utc)
# Write metric row
metric = PluginMetric(
source_module=source_module,
resource_name=resource_name,
metric_name=metric_name,
value=value,
recorded_at=now,
)
session.add(metric)
await session.flush()
# Check active maintenance windows — skip rule evaluation if suppressed
mw_result = await session.execute(
select(MaintenanceWindow).where(
MaintenanceWindow.start_at <= now,
MaintenanceWindow.end_at >= now,
or_(
MaintenanceWindow.scope_source.is_(None),
and_(
MaintenanceWindow.scope_source == source_module,
or_(
MaintenanceWindow.scope_resource.is_(None),
MaintenanceWindow.scope_resource == resource_name,
),
),
),
).limit(1)
)
if mw_result.scalar_one_or_none() is not None:
return # suppressed by maintenance window
# Load matching enabled rules
result = await session.execute(
select(AlertRule).where(
AlertRule.source_module == source_module,
AlertRule.resource_name == resource_name,
AlertRule.metric_name == metric_name,
AlertRule.enabled.is_(True),
)
)
rules = result.scalars().all()
for rule in rules:
state_result = await session.execute(
select(AlertState).where(AlertState.rule_id == rule.id)
)
alert_state = state_result.scalar_one_or_none()
if alert_state is None:
logger.warning(f"No alert_state row for rule {rule.id}, skipping")
continue
notifications = await _evaluate_rule(session, rule, alert_state, value, now)
for notif_type, event_id in notifications:
if _app is not None:
asyncio.create_task(
_dispatch_notification(
_app, notif_type, rule, value, event_id
)
)
# Admin-configured Ansible action runs only on transition-to-firing.
if notif_type == "firing" and rule.ansible_action:
asyncio.create_task(
_run_ansible_action(_app, rule, value, event_id)
)
def _is_breached(value: float, operator: AlertOperator, threshold: float) -> bool:
op = operator.value
if op == ">":
return value > threshold
if op == "<":
return value < threshold
if op == ">=":
return value >= threshold
if op == "<=":
return value <= threshold
if op == "==":
return value == threshold
if op == "!=":
return value != threshold
return False
@dataclass(frozen=True)
class Step:
"""One sample's effect on an alert: the state after it, the two run
counters, and the event to record ("firing" / "resolved") if any."""
state: AlertStateEnum
fail_count: int
ok_count: int
event: str | None = None
def next_step(state: AlertStateEnum, fail_count: int, ok_count: int, breached: bool,
fail_required: int, ok_required: int) -> Step:
"""The alert state machine, as a pure function of one sample.
inactive → pending → firing when `fail_required` breaching checks run in a
row; a non-breaching check while pending goes back to inactive.
firing and acknowledged resolve (to inactive, with a resolved event) only
after `ok_required` non-breaching checks in a row; a breaching check
resets that run. An acknowledgement holds while the alert is still
breached: only a resolve clears it.
"""
fail_required, ok_required = max(1, fail_required), max(1, ok_required)
S = AlertStateEnum
if state in (S.firing, S.acknowledged):
if breached:
return Step(state, fail_count + 1, 0)
if ok_count + 1 >= ok_required:
return Step(S.inactive, 0, 0, "resolved")
return Step(state, fail_count, ok_count + 1)
# inactive, pending (and the transient resolved, read as inactive)
if not breached:
return Step(S.inactive, 0, 0)
fails = fail_count + 1 if state == S.pending else 1
if fails >= fail_required:
return Step(S.firing, fails, 0, "firing")
return Step(S.pending, fails, 0)
async def _evaluate_rule(
session: AsyncSession,
rule: AlertRule,
state: AlertState,
value: float,
now: datetime,
) -> list[tuple[str, str]]:
"""Apply one sample to a rule's state. Returns [(notif_type, event_id)]."""
from_state = state.state
step = next_step(from_state, state.consecutive_failure_count, state.consecutive_ok_count,
_is_breached(value, rule.operator, rule.threshold),
rule.consecutive_failures_required, rule.consecutive_ok_required)
state.consecutive_failure_count = step.fail_count
state.consecutive_ok_count = step.ok_count
notifications: list[tuple[str, str]] = []
if step.state != from_state:
state.state = step.state
state.last_transition_at = now
if step.state == AlertStateEnum.inactive:
state.acknowledged_by = None
state.acknowledged_at = None
if step.event:
event_id = _add_event(session, rule.id, from_state.value, step.event, value, now)
notifications.append((step.event, event_id))
await session.flush()
return notifications
async def reset_rule_state(session: AsyncSession, rule: AlertRule, note: str) -> None:
"""Put a rule's alert back to inactive because the rule itself changed
(what it watches, its threshold, or it was disabled). An alert that was
firing or acknowledged gets a resolved event carrying `note`; nobody is
notified, since nothing about the watched resource changed."""
state = (await session.execute(
select(AlertState).where(AlertState.rule_id == rule.id))).scalar_one_or_none()
if state is None:
return
now = datetime.now(timezone.utc)
if state.state in (AlertStateEnum.firing, AlertStateEnum.acknowledged):
_add_event(session, rule.id, state.state.value, "resolved", None, now, note=note)
if state.state != AlertStateEnum.inactive:
state.last_transition_at = now
state.state = AlertStateEnum.inactive
state.consecutive_failure_count = 0
state.consecutive_ok_count = 0
state.acknowledged_by = None
state.acknowledged_at = None
def _add_event(
session: AsyncSession,
rule_id: str,
from_state: str,
to_state: str,
value: float | None,
now: datetime,
note: str | None = None,
) -> str:
"""Add an AlertEvent row and return its ID."""
event_id = str(uuid.uuid4())
event = AlertEvent(
id=event_id,
rule_id=rule_id,
from_state=from_state,
to_state=to_state,
metric_value=value,
transitioned_at=now,
note=note,
)
session.add(event)
return event_id
async def _dispatch_notification(
app: "Quart",
notif_type: str,
rule: AlertRule,
value: float,
event_id: str,
) -> None:
"""Run after the transaction commits. Sends notifications and updates the event row."""
from steward.core.notifications import dispatch_notifications
alert_data = {
"rule_name": rule.name,
"state": notif_type.upper(),
"metric": rule.metric_name,
"value": value,
"threshold": rule.threshold,
"resource": rule.resource_name,
"source_module": rule.source_module,
"timestamp": datetime.now(timezone.utc).isoformat(),
}
smtp_cfg = app.config.get("SMTP", {})
webhook_cfg = app.config.get("WEBHOOK", {})
results = await dispatch_notifications(smtp_cfg, webhook_cfg, alert_data)
# Update event row with delivery results in a new transaction
async with app.db_sessionmaker() as db:
async with db.begin():
event_result = await db.execute(
select(AlertEvent).where(AlertEvent.id == event_id)
)
event = event_result.scalar_one_or_none()
if event:
email_r = results.get("email")
if email_r:
event.email_sent = email_r["sent"]
event.email_error = email_r.get("error")
webhook_r = results.get("webhook")
if webhook_r:
event.webhook_sent = webhook_r["sent"]
event.webhook_error = webhook_r.get("error")
async def _run_ansible_action(
app: "Quart",
rule: AlertRule,
value: float,
event_id: str,
) -> None:
"""Run the rule's configured Ansible playbook (system-triggered).
Runs after the evaluation transaction commits (scheduled via create_task).
Creates a system-triggered AnsibleRun, links it to the firing AlertEvent,
then executes it with the static params plus injected alert context vars.
"""
from steward.ansible import executor, sources as src_module
from steward.models.ansible import AnsibleRun, AnsibleRunStatus
action = rule.ansible_action or {}
playbook = action.get("playbook")
inventory = action.get("inventory")
if not playbook or not inventory:
logger.error("Ansible action for rule %r missing playbook/inventory", rule.name)
return
try:
srcs = src_module.get_sources(app.config.get("ANSIBLE", {}))
except Exception:
logger.exception("Ansible action for rule %r: could not load sources", rule.name)
return
source = next((s for s in srcs if s["name"] == action.get("source")), None)
if source is None:
logger.error("Ansible action for rule %r: source %r not configured",
rule.name, action.get("source"))
return
# Static params + auto-injected alert context (all argv, never shell).
params: dict = {
"extra_vars": list(action.get("extra_vars") or []) + alert_extra_vars(rule, value),
}
if action.get("limit"):
params["limit"] = action["limit"]
if action.get("tags"):
params["tags"] = action["tags"]
if action.get("check"):
params["check"] = True
run_id = str(uuid.uuid4())
async with app.db_sessionmaker() as db:
async with db.begin():
db.add(AnsibleRun(
id=run_id,
playbook_path=playbook,
inventory_path=inventory,
source_name=source["name"],
triggered_by=None,
status=AnsibleRunStatus.running,
params=params,
))
event = (await db.execute(
select(AlertEvent).where(AlertEvent.id == event_id))).scalar_one_or_none()
if event:
event.ansible_run_id = run_id
await executor.start_run(app, run_id, playbook, inventory, source["path"], params)