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FabledSteward/plugins/docker/swarm_health.py
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bvandeusenandClaude Opus 5.5 0b787a0676
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fix(alerts): an alert on a count says how many of what, and names them (#6400)
"swarm services short on swarm is 6." becomes "6 swarm services are
short of their replicas.", with a Which line naming each service and how
many of its tasks run. The swarm figures get labels, and the counting
figures (swarm, mounts, drives, updates) read as sentences in the email,
its subject and the Alerts page. A plugin names what its count counts
through core.alerts.names_behind; the Docker plugin does for the three
swarm figures, from the stored swarm. Webhooks get alert.which too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-25 13:00:56 -04:00

112 lines
5.1 KiB
Python

"""The swarm's health as three figures an alert rule can watch (#5788).
Every manager's agent reports the whole swarm, so the figures are swarm-wide,
on one resource, `swarm`, and are recorded at most once every RECORD_EVERY
whichever manager sent them: three managers then read as one series, and one
manager going silent doesn't silence it.
- swarm_services_short: services running fewer tasks than they want. A
service scaled to 0 wants none and is never short.
- swarm_nodes_down: nodes whose status isn't ready, other than drained ones.
A drained node is one taken out of service on purpose (VDNT-Util01 always;
any node during its maintenance), so its going away is expected. Its host's
own "Agent offline" rule still covers it.
- swarm_managers_unreachable: managers the swarm can't reach (agent 1.19.0
sends ManagerStatus.Reachability; before that, a manager whose status
isn't ready), drained ones aside for the same reason. With three managers
one can be lost and the swarm keeps working; two, and it can't change.
A maintenance job on a swarm node holds these rules' notifications in its
window (host_agent maintenance._swarm_window), since draining and rebooting a
node is exactly what moves them.
"""
from __future__ import annotations
from datetime import datetime, timedelta
RESOURCE = "swarm"
SWARM_METRICS = ("swarm_services_short", "swarm_nodes_down", "swarm_managers_unreachable")
RECORD_EVERY = timedelta(seconds=30)
_last_recorded: datetime | None = None
def short_services(services: list[dict]) -> list[str]:
"""The services swarm_services_short counts, each with how many of its
tasks run: "web_app (0 of 2 running)"."""
return [f"{s.get('service_name')} ({int(s.get('running') or 0)} of {int(s.get('desired') or 0)} running)"
for s in sorted(services, key=lambda s: s.get("service_name") or "")
if int(s.get("desired") or 0) > 0 and int(s.get("running") or 0) < int(s.get("desired") or 0)]
def _in_service(nodes: list[dict]) -> list[dict]:
return sorted((n for n in nodes if (n.get("availability") or "active") != "drain"),
key=lambda n: n.get("hostname") or "")
def down_nodes(nodes: list[dict]) -> list[str]:
"""The nodes swarm_nodes_down counts, by hostname, with their status."""
return [f"{n.get('hostname') or n.get('node_id')} ({n.get('status') or 'unknown'})"
for n in _in_service(nodes) if (n.get("status") or "unknown") != "ready"]
def unreachable_managers(nodes: list[dict]) -> list[str]:
"""The managers swarm_managers_unreachable counts, by hostname."""
return [n.get("hostname") or n.get("node_id") for n in _in_service(nodes)
if n.get("role") == "manager"
and (n["reachability"] != "reachable" if n.get("reachability")
else (n.get("status") or "unknown") != "ready")]
def figures(swarm: dict) -> dict[str, float]:
"""The three figures from one manager's swarm report."""
services = swarm.get("services") or []
nodes = swarm.get("nodes") or []
return {"swarm_services_short": float(len(short_services(services))),
"swarm_nodes_down": float(len(down_nodes(nodes))),
"swarm_managers_unreachable": float(len(unreachable_managers(nodes)))}
async def _stored(session) -> tuple[list[dict], list[dict]]:
"""The swarm's services and nodes as stored, the newest report of each
when more than one manager reported it, in the shape figures() reads.
A stored node has no reachability, so its status stands in for it."""
from sqlalchemy import select
from .mcp_tools import unique_nodes
from .models import DockerSwarmNode, DockerSwarmService
services: dict[str, DockerSwarmService] = {}
for s in (await session.execute(select(DockerSwarmService))).scalars():
if s.service_name not in services or s.updated_at > services[s.service_name].updated_at:
services[s.service_name] = s
nodes = unique_nodes(list((await session.execute(select(DockerSwarmNode))).scalars()))
return ([{"service_name": s.service_name, "desired": s.desired, "running": s.running}
for s in services.values()],
[{"node_id": n.node_id, "hostname": n.hostname, "role": n.role,
"availability": n.availability, "status": n.status} for n in nodes])
async def name_short_services(session, resource: str) -> list[str]:
return short_services((await _stored(session))[0])
async def name_down_nodes(session, resource: str) -> list[str]:
return down_nodes((await _stored(session))[1])
async def name_unreachable_managers(session, resource: str) -> list[str]:
return unreachable_managers((await _stored(session))[1])
NAMERS = {"swarm_services_short": name_short_services, "swarm_nodes_down": name_down_nodes,
"swarm_managers_unreachable": name_unreachable_managers}
def due(now: datetime) -> bool:
"""Whether this report should be recorded: the first in RECORD_EVERY,
whichever manager it came from."""
global _last_recorded
if _last_recorded is not None and now - _last_recorded < RECORD_EVERY:
return False
_last_recorded = now
return True