oxynote/server/core/internal/datasource/AGENTS.md

AGENTS.md

Outbound data-source connections and the built-in demo source. Go standards live in server/core/AGENTS.md.

The demo data source

Every organization is seeded, unconditionally, with a Prometheus data source "Demo" at demo://engineering, and the welcome document whose charts query it.

• demo/ synthesises the metrics in-process. runner.ensurePrepared picks it for exactly that URL; any other demo:// is demo.ErrUnknownSource. The type stays prometheus, so nothing downstream can tell.
• One demo.Client lives on datasource.Manager for the whole process, because its registry walks cache replayed history; a runner is built per call.
• The timeline is a pure function of the tick (fixed epoch, one-minute tick, per-series seed), so history never rewrites and any window backfills. walk.checkpoint caches one value per day-long segment.
• Queries run through the official promql engine over a storage.Queryable synthesising only the requested window, at the query's step.
• registry.go declares every metric family. Test_welcomeDocumentQueries runs every query in internal/document/files/available_metrics.json against it.

Processor tests

processor/ starts throwaway MariaDB and Postgres containers (gnomock) to cover real connection, query and read-only-check paths; docker is a unit-test dependency here, as in internal/db.