The httpRequestDuration histogram labeled every request with the raw URL
path (`url.split("?")[0]`), so every distinct path — `/activities/<uuid>`,
`/routes/<uuid>`, probed usernames, crawler junk — became a permanent
label-set. prom-client never evicts label-sets, so RSS grew linearly for
the life of the process and reset only on restart. On the flagship this
showed as ~25 MiB/day of unbounded journal memory growth; a live
`/api/metrics` scrape held 2,655 histogram series across 291 distinct
`route` values (344 KB body), dominated by per-UUID activity paths.
Add `normalizeRoute()` in metrics.server.ts: it collapses dynamic path
segments back to the `:param` templates declared in app/routes.ts (UUID
and numeric segments -> `:id`; `:username`/`:provider` slots keyed by
their preceding static segment), strips query/fragment, and enforces a
hard cap (MAX_ROUTES) that funnels anything beyond the known route table
into a single `/other` bucket as an absolute backstop. Cardinality is now
proportional to the route table, not to traffic.
Logs still record the raw path (`logger.info`) — only the metric label is
bounded.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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