Files
FabledSteward/plugins/host_agent/metrics_query.py
T
bvandeusenandClaude Opus 5.5 b8f73270e7
CI / lint (push) Successful in 3s
CI / integration (push) Failing after 1m14s
CI / unit (push) Successful in 1m33s
CI / publish (push) Skipped
perf(metrics): a latest-value table for "what is it now"; dashboard cells say loading, failed and as-of (#5208)
The dashboard's host widgets took 18-60 s. Every "latest reading" query
(hosts overview, host-agent fleet, host page, vitals, SNMP, MCP get_host)
searched plugin_metrics for the newest row per metric. Postgres has no skip
scan, so each one read every raw sample in the 7-day window.

- plugin_metric_latest: one row per (source, resource, metric).
  record_metrics upserts it in the same transaction, moving forward only and
  in sorted key order. Migration 0030 seeds it by stepping the existing index.
- Retention drops a latest row once its sample leaves the raw window, so a
  resource that stopped reporting disappears when its history does, as before.
  Renames carry it along.
- A quiet host keeps its last values, marked stale. A time-bounded query
  would have shown it as missing.
- Vitals sparklines span the 6 h they claim, averaged in SQL to ~120 points,
  instead of fetching 6 h raw and drawing the last 120 samples.
- Dashboard and share-view cells: "Loading…" until the first answer; a 20 s
  deadline per fetch; "Couldn't load (why)" with Retry now and an automatic
  retry for cells that don't poll; "as of HH:MM" in the header, and
  "couldn't refresh · as of" when a refresh fails over shown data.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-06 23:06:34 -04:00

97 lines
4.3 KiB
Python

"""Host-metric read helpers (latest snapshot + bucketed history).
Kept separate from routes.py so it imports only the core PluginMetric model — not
the host_agent ORM models — which lets integration tests import these helpers
without tripping the plugin-loader's double-registration ("Table already
defined") guard.
"""
from __future__ import annotations
from datetime import datetime, timedelta, timezone
from sqlalchemy import func, select
from steward.core.time_range import bucket_seconds
from steward.models.metrics import PluginMetric, PluginMetricHourly
SOURCE_MODULE = "host_agent"
# Host-level metrics charted on the detail page (sub-resources are shown as
# current-value lists, not time series, to keep the page readable).
HISTORY_METRICS = (
"cpu_pct", "mem_used_pct", "disk_used_pct_worst", "load_1m",
"net_rx_bps", "net_tx_bps", "disk_read_bps", "disk_write_bps",
"temp_c_max", "psi_mem_some_avg10",
)
async def _latest_metrics_for_host(session, host_name: str) -> dict[str, dict[str, float]]:
"""{resource_name: {metric: value}} — latest sample per (resource, metric) for
a host + its sub-resources, from plugin_metric_latest (#5208). A host whose
agent has gone quiet keeps its last values until they age out of the raw
window; the caller decides staleness from the registration's last_seen_at.
"""
from steward.core.metric_series import latest_values
out: dict[str, dict[str, float]] = {}
for r in await latest_values(session, SOURCE_MODULE, host_name, include_children=True):
out.setdefault(r.resource_name, {})[r.metric_name] = r.value
return out
async def _history_for_host(session, host_name: str, since, *, raw_days: int = 7) -> dict[str, list]:
"""{metric: [[epoch_ms, avg_value], …]} host-level series since `since`.
Retention rolls raw plugin_metrics older than `raw_days` into hourly averages
(plugin_metrics_hourly) and deletes the raw rows. So we read the rollup for the
part of the range older than that boundary and raw (bucket-averaged in SQL,
capped to ≤1h to match the rollup) for the recent part — never shipping raw
samples to Python. The two windows don't overlap, so appending hourly-then-raw
keeps each metric's series time-ordered. Epoch-ms x feeds a linear chart axis.
"""
now = datetime.now(timezone.utc)
raw_cutoff = (now - timedelta(days=raw_days)).replace(minute=0, second=0, microsecond=0)
series: dict[str, list] = {m: [] for m in HISTORY_METRICS}
# ── Older than the raw window: the hourly rollup ──
if since < raw_cutoff:
hourly = (await session.execute(
select(PluginMetricHourly.metric_name, PluginMetricHourly.bucket,
PluginMetricHourly.value_avg)
.where(
PluginMetricHourly.source_module == SOURCE_MODULE,
PluginMetricHourly.resource_name == host_name,
PluginMetricHourly.metric_name.in_(HISTORY_METRICS),
PluginMetricHourly.bucket >= since,
PluginMetricHourly.bucket < raw_cutoff,
)
.order_by(PluginMetricHourly.bucket)
)).all()
for metric_name, bucket, avg in hourly:
series[metric_name].append([int(bucket.timestamp() * 1000), round(float(avg), 2)])
# ── Recent part: raw, bucket-averaged in SQL ──
raw_since = since if since >= raw_cutoff else raw_cutoff
width_s = bucket_seconds(raw_since, 120)
if since < raw_cutoff:
width_s = min(width_s, 3600) # ≤ 1h so it matches the hourly portion
rbucket = func.date_bin(
func.make_interval(0, 0, 0, 0, 0, 0, width_s),
PluginMetric.recorded_at,
func.to_timestamp(0), # epoch origin
).label("bucket")
raw = (await session.execute(
select(PluginMetric.metric_name, rbucket, func.avg(PluginMetric.value))
.where(
PluginMetric.source_module == SOURCE_MODULE,
PluginMetric.resource_name == host_name,
PluginMetric.metric_name.in_(HISTORY_METRICS),
PluginMetric.recorded_at >= raw_since,
)
.group_by(PluginMetric.metric_name, rbucket)
.order_by(rbucket)
)).all()
for metric_name, b, avg in raw:
series[metric_name].append([int(b.timestamp() * 1000), round(float(avg), 2)])
return series