#5061 "Metric catalog belongs to what emits: plugins register their
metrics; names match what is recorded".
- The static METRIC_CATALOG is gone. metric_catalog() is core's own sources
(the four monitor types and "steward", the app's open_fds/open_fds_pct,
which were recorded but never offered) plus each loaded plugin's
get_alert_metrics() export. A disabled plugin's sources leave the picker.
- traefik offers what it records: error_rate_4xx_pct and error_rate_5xx_pct.
The old "error_rate" was never recorded, so a rule on it could not fire.
- tests/core/test_metric_catalog.py walks every MetricBatch.add /
record_metric call (traefik's tuple loop included) and fails on a recorded
metric the catalog lacks; it shows on a synthetic writer that it can fail.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
bvandeusenandClaude Opus 5.5
0742b7a2b7