The CPU/Memory/Disk gauges read `server.metrics`, the same key the
per-server status endpoint uses (servers.py:757). The list endpoint never
populated it -- to_dict() defaults to include_metrics=False, and even when
asked it emits `latest_metrics` -- so on a live panel every gauge cell fell
back to the "no data" dash.
It survived because the screenshot fixtures DO supply `metrics`
(sections.mjs:294): the UI looked correct in every capture and was empty in
production. The fixture had encoded the intended contract; the backend never
implemented it.
Batched deliberately: Server.metrics is lazy='dynamic', so the obvious
per-row lookup costs one extra SELECT per server. Newest row per server =
highest id (autoincrement on insert), which also avoids the tie a
max(timestamp) join hits for same-second rows -- two queries total,
regardless of server count.
Tests pin all three properties, and each fails without the fix: the key and
field names the table reads, absence (not {}) for a server that never
reported, and that the query count stays flat as servers are added.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
