slmm/CHANGELOG.md

Changelog

All notable changes to SLMM (Sound Level Meter Manager) will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[0.2.1] - 2026-01-23

Added

• Roster management: UI and API endpoints for managing device rosters.
• Delete config endpoint: Remove device configuration alongside cached status data.
• Scheduler hooks: start_cycle and stop_cycle helpers for Terra-View scheduling integration.

Changed

• FTP logging: Connection, authentication, and transfer phases now log explicitly.
• Documentation: Reorganized docs/scripts and updated API notes for FTP/TCP verification.

[0.2.0] - 2026-01-15

Added

Background Polling System

• Continuous automatic device polling - Background service that continuously polls configured devices
• Per-device configurable intervals - Each device can have custom polling interval (10-3600 seconds, default 60)
• Automatic offline detection - Devices automatically marked unreachable after 3 consecutive failures
• Reachability tracking - Database fields track device health with failure counters and error messages
• Dynamic sleep scheduling - Polling service adjusts sleep intervals based on device configurations
• Graceful lifecycle management - Background poller starts on application startup and stops cleanly on shutdown

New API Endpoints

• GET /api/nl43/{unit_id}/polling/config - Get device polling configuration
• PUT /api/nl43/{unit_id}/polling/config - Update polling interval and enable/disable per-device polling
• GET /api/nl43/_polling/status - Get global polling status for all devices with reachability info

Database Schema Changes

• NL43Config table:

  • poll_interval_seconds (Integer, default 60) - Polling interval in seconds
  • poll_enabled (Boolean, default true) - Enable/disable background polling per device

• NL43Status table:

  • is_reachable (Boolean, default true) - Current device reachability status
  • consecutive_failures (Integer, default 0) - Count of consecutive poll failures
  • last_poll_attempt (DateTime) - Last time background poller attempted to poll
  • last_success (DateTime) - Last successful poll timestamp
  • last_error (Text) - Last error message (truncated to 500 chars)

New Files

• app/background_poller.py - Background polling service implementation
• migrate_add_polling_fields.py - Database migration script for v0.2.0 schema changes
• test_polling.sh - Comprehensive test script for polling functionality
• CHANGELOG.md - This changelog file

Changed

• Enhanced status endpoint - GET /api/nl43/{unit_id}/status now includes polling-related fields (is_reachable, consecutive_failures, last_poll_attempt, last_success, last_error)
• Application startup - Added lifespan context manager in app/main.py to manage background poller lifecycle
• Performance improvement - Terra-View requests now return cached data instantly (<100ms) instead of waiting for device queries (1-2 seconds)

Technical Details

Architecture

• Background poller runs as async task using asyncio.create_task()
• Uses existing NL43Client and persist_snapshot() functions - no code duplication
• Respects existing 1-second rate limiting per device
• Efficient resource usage - skips work when no devices configured
• WebSocket streaming remains unaffected - separate real-time data path

Default Behavior

• Existing devices automatically get 60-second polling interval
• Existing status records default to is_reachable=true
• Migration is additive-only - no data loss
• Polling can be disabled per-device via poll_enabled=false

Recommended Intervals

• Critical monitoring: 30 seconds
• Normal monitoring: 60 seconds (default)
• Battery conservation: 300 seconds (5 minutes)
• Development/testing: 10 seconds (minimum allowed)

Migration Notes

To upgrade from v0.1.x to v0.2.0:

1. Stop the service (if running):

   docker compose down slmm
   # OR
   # Stop your uvicorn process
   

2. Update code:

   git pull
   # OR copy new files
   

3. Run migration:

   cd slmm
   python3 migrate_add_polling_fields.py
   

4. Restart service:

   docker compose up -d --build slmm
   # OR
   uvicorn app.main:app --host 0.0.0.0 --port 8100
   

5. Verify polling is active:

   curl http://localhost:8100/api/nl43/_polling/status | jq '.'
   

You should see "poller_running": true and all configured devices listed.

Breaking Changes

None. This release is fully backward-compatible with v0.1.x. All existing endpoints and functionality remain unchanged.

---

[0.1.0] - 2025-12-XX

Added

• Initial release
• REST API for NL43/NL53 sound level meter control
• TCP command protocol implementation
• FTP file download support
• WebSocket streaming for real-time data (DRD)
• Device configuration management
• Measurement control (start, stop, pause, resume, reset, store)
• Device information endpoints (battery, clock, results)
• Measurement settings management (frequency/time weighting)
• Sleep mode control
• Rate limiting (1-second minimum between commands)
• SQLite database for device configs and status cache
• Health check endpoints
• Comprehensive API documentation
• NL43 protocol documentation

Database Schema (v0.1.0)

• NL43Config table - Device connection configuration
• NL43Status table - Measurement snapshot cache

---

Version History Summary

• v0.2.1 (2026-01-23) - Roster management, scheduler hooks, FTP logging, doc cleanup
• v0.2.0 (2026-01-15) - Background Polling System
• v0.1.0 (2025-12-XX) - Initial Release