Every Store interface method (except Close) now takes context.Context
as first parameter. All 54 db.Query/Exec/QueryRow calls in SQLStore
replaced with their *Context variants. DB operations now respect
cancellation and deadlines.
Context sources by caller:
- Engine dbWriter/poll/pruner: engine ctx from Start()
- HTTP handlers: r.Context()
- config.Apply/Export: caller-provided ctx
- TUI/main.go init: context.Background()
RunCheck and all sub-checks (HTTP/ping/port/DNS) accept parent ctx.
HTTP checks now inherit shutdown cancellation instead of rooting in
context.Background(). dbWrite.exec takes ctx so the writer goroutine
can cancel stuck DB operations.
DeleteSite/ImportData use BeginTx(ctx) instead of Begin().
1. Group auto-pause trap: remove the one-way Paused=true mutation
from checkGroup — monitorRoutine skipped paused groups, so they
could never re-evaluate or auto-unpause.
2. Retry logic: apply MaxRetries to all →DOWN transitions, not just
UP→DOWN. New monitors (PENDING) no longer alert on first transient
failure when retries are configured.
3. Shutdown drain hole: track checker goroutines with checkerWG so
Stop() waits for in-flight checks before draining the write queue.
Final drainWrites() catches any writes enqueued after the writer's
own drain.
4. Probe-ingest writer bypass: route SaveCheckFromNode through the
engine's serialized dbWriter instead of writing directly to the
store from the HTTP handler.
5. Dead-probe expiry: expire stale probe results (>3× site interval)
before aggregation so a dead probe can't poison status forever.
Also clean probeResults in RemoveSite.
6. Maintenance-cache N+1: replace per-check DB query with a
fully-resolved in-memory cache refreshed every poll cycle. One
GetActiveMaintenanceWindows() call instead of N IsMonitorInMaintenance.
ImportData now wipes check_history, state_changes, and alert_health
so re-inserted IDs don't inherit stale history from prior occupants.
Every check spawned `go e.db.Save*(...)` with the error discarded: a
fire-and-forget goroutine per log line, check, state change, and alert
health update. SaveLog ran a full-table prune DELETE on every insert and
SaveCheck a COUNT + conditional prune on every check, so the hot path
amplified each write into several statements. Nothing tracked these
goroutines, so at shutdown they raced the store's Close() — writes to a
closing DB, silently swallowed.
Introduce a single writer goroutine that drains a buffered channel of
typed dbWrite values (log/check/state-change/alert-health). Writes are
enqueued non-blocking; a saturated queue drops and notes it in the
in-memory log rather than blocking the check loop. Write errors are now
logged instead of discarded. Retention moves off the hot path: SaveLog
and SaveCheck become plain INSERTs, and PruneLogs/PruneCheckHistory/
PruneStateChanges run on a 10-minute timer inside the writer (single
keep-newest-N-per-site pass via a window function). state_changes was
previously never pruned — now bounded.
Add Engine.Stop(): cancels the engine's context, then waits for the
writer to drain every buffered write before returning. main wires it in
before the deferred store Close() so no write races a closed DB.
SQLite gains busy_timeout=5000 and synchronous=NORMAL, applied via the
DSN so every pooled connection inherits them (a post-open PRAGMA only
touches one connection); WAL moves to the DSN too. :memory: test DBs are
left as-is.
Tests: writer drains on Stop, Stop is idempotent, and the prune queries
keep newest-N per site / N logs on real SQLite. Full suite green under
-race.
lerko
