observability

Overview ¶

Example: observability

Demonstrates drel's production observability surface — all opt-in via Options passed to Open, plus the OnQuery hook:

• WithLogger + WithQueryLog: structured slog line for every query.
• WithSlowQueryThreshold: queries slower than the threshold are flagged.
• WithTracer: one span per executed query (OpenTelemetry-style). This example plugs in a tiny in-memory tracer that counts spans.
• WithDevMode: development-time diagnostics — here it warns about an unbounded SELECT (no LIMIT).
• OnQuery: a raw hook receiving SQL, args, duration, and error for custom metrics/audit.

Runs against in-memory SQLite (pure-Go modernc.org/sqlite, no CGO).

Usage:

cd examples/observability
go run ../../cmd/drel generate   # generates catalog/product_drel.go + db/drel_gen.go
go run .