the-other-dude/.planning/phases/15-signal-trending-site-alerting/15-02-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
15-signal-trending-site-alerting	02	api	asyncio signal-trending alerting typescript scheduled-tasks	phase provides 14-wireless-sector-management wireless_links, sectors, devices with site_id	Hourly signal trend detection comparing 7d vs 14d averages 5-minute alert rule evaluation with hysteresis for 4 rule types Frontend API clients for signal history, alert rules, and alert events	15-signal-trending-site-alerting	added patterns asyncio background task with getattr fallback for config hysteresis via consecutive_hits counter	created modified backend/app/services/trend_detector.py backend/app/services/alert_evaluator_site.py backend/app/main.py frontend/src/lib/api.ts	Used getattr with fallback for config settings (SIGNAL_DEGRADATION_THRESHOLD_DB etc.) so services work before Plan 01 adds them to Settings class Trend detector derives site_id via JOIN on devices table since wireless_links has no direct site_id column Alert events created with consecutive_hits=1 immediately; UI/API filters for >= 2 to show confirmed alerts Severity auto-assigned: critical for device_offline rules, warning for sector signal/client rules	Hysteresis pattern: create event at hits=1, confirm at hits>=2, auto-resolve when condition clears Scheduled task pattern: getattr config fallback, AdminAsyncSessionLocal, raw SQL for cross-tenant system queries	TRND-02 ALRT-01 ALRT-02	3min	2026-03-19

Phase 15 Plan 02: Signal Trending & Alert Evaluation Summary

Hourly trend detection comparing 7d/14d signal averages plus 5-minute alert rule evaluation with hysteresis across 4 rule types, with TypeScript API clients for Plan 03 UI

Performance

• Duration: 3 min
• Started: 2026-03-19T12:14:19Z
• Completed: 2026-03-19T12:17:00Z
• Tasks: 2
• Files modified: 4

Accomplishments

• Trend detector scans active/degraded wireless links hourly, creates signal_degradation alerts when 7d avg drops 5+ dB from 14d baseline
• Alert evaluator checks all enabled rules every 5 minutes with hysteresis (2 consecutive hits before confirming)
• Both tasks wired into lifespan with non-fatal startup and graceful cancel on shutdown
• Three frontend API clients (signalHistoryApi, alertRulesApi, alertEventsApi) ready for Plan 03 UI components

Task Commits

Each task was committed atomically:

1. Task 1: Create trend detection and alert evaluation scheduled tasks - c3ae48e (feat)
2. Task 2: Add frontend TypeScript API clients - b9a92f3 (feat)

Files Created/Modified

• backend/app/services/trend_detector.py - Hourly signal trend detection loop
• backend/app/services/alert_evaluator_site.py - 5-minute alert rule evaluation with hysteresis
• backend/app/main.py - Wired both tasks into lifespan startup/shutdown
• frontend/src/lib/api.ts - Added signalHistoryApi, alertRulesApi, alertEventsApi clients

Decisions Made

• Used getattr with fallback for config settings so services work before Plan 01 adds settings to the Settings class
• Derived site_id via JOIN on devices table since wireless_links has no direct site_id FK
• Alert events created immediately with consecutive_hits=1; confirmed when hits reach 2
• Auto-assigned severity: critical for device_offline rules, warning for sector-scoped rules

Deviations from Plan

None - plan executed exactly as written.

Issues Encountered

None.

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• Backend scheduled tasks ready for signal degradation detection and alert evaluation
• Frontend API clients ready for Plan 03 UI components (signal charts, alert rules tab, notification bell)
• Depends on Plan 01 completing first (database tables, config settings, router endpoints)

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Phase: 15-signal-trending-site-alerting Completed: 2026-03-19