fleet/server/chart/CLAUDE.md

Chart bounded context

Before working in server/chart/, read README.md — it covers the architecture, the SCD + bitmap data model, sample strategies, and a step-by-step guide for adding new datasets and charts.

Quick reminders (full detail in the README):

• This is a self-contained bounded context. No chart package may import server/fleet or server/contexts/viewer — arch_test.go enforces this. Bridge to legacy Fleet via a narrow api interface implemented in server/acl/chartacl.
• External code only touches bootstrap.New and the api package.
• Data lives in one table, host_scd_data (slowly-changing-dimension type-2), with host-sets stored as roaring bitmaps. Work in op form (*roaring.Bitmap); only cross the storage boundary via BitmapToBlob / DecodeBitmap.
• Mind the nil vs empty-slice semantics on HostFilter.TeamIDs and GetSCDData entityIDs — they are load-bearing; don't normalize them away.
• Snapshot collectors must call RecordBucketData even with an empty map (it closes open rows). Accumulate collectors may skip empty input.
• Adding a dataset: implement api.Dataset in datasets.go, add any store method to both api.DatasetStore and internal/types.Datastore, register it in cmd/fleet/serve.go, and wire config gating + scrub in server/fleet/historical_data.go if it's opt-in/out.