Files
ledgrab/server
alexei.dolgolyov e24f9d33cc fix(shutdown): survive PC restart with WAL fsync + Win32 session-end guard
Two bugs caused user data ('G502' target's color-strip ref, etc.) to
revert after PC restart while persisting fine across normal app
restarts:

1. SQLite was in WAL mode with synchronous=NORMAL and Database.close()
   was never called. On graceful Python exit the sqlite3 finalizer
   checkpoints the WAL, but on an unclean PC shutdown (power loss,
   forced reboot, or Windows force-terminating pythonw.exe) the WAL
   stayed in OS cache, never reached disk, and the next boot rolled the
   DB back to the last checkpoint -- losing recent edits.

2. Nothing handled WM_QUERYENDSESSION / WM_ENDSESSION, so on PC
   shutdown Windows force-killed pythonw.exe after ~5s and the FastAPI
   lifespan never ran. The 'stop_targets' setting was silently ignored
   and devices were left at their last frame.

Changes:
- Database: PRAGMA synchronous=FULL + wal_autocheckpoint=100, plus an
  explicit wal_checkpoint(TRUNCATE) inside Database.close().
- New utils/win_shutdown.py: hidden top-level window in a daemon thread
  with a ctypes WindowProc that catches WM_QUERYENDSESSION (calls
  ShutdownBlockReasonCreate to extend Windows' 5s hung-app timeout up
  to the ~20s GUI ceiling), fires the shutdown callback, then waits in
  WM_ENDSESSION on a completion event before returning. Also raises
  the process shutdown priority via SetProcessShutdownParameters. All
  Win32 argtypes/restypes are bound once at import to avoid LPARAM
  overflow on x64.
- New shutdown_state.py: leaf module owning the cross-thread Event so
  __main__ does not import the heavy ledgrab.main at startup.
- main.py lifespan: per-step asyncio.wait_for budgets (8s for
  processor_manager.stop_all, 1.5s each for HA/MQTT, etc.) so a hung
  device cannot starve the DB checkpoint, then db.close() and
  shutdown_complete.set() always run.
- __main__.py: install the Windows shutdown guard before tray start;
  install SIGINT/SIGTERM/SIGBREAK handlers only on the tray path
  (uvicorn overwrites them on no-tray); raise server_thread.join to 20s.
- Tests cover WM_QUERYENDSESSION (fires callback, returns TRUE,
  idempotent), WM_ENDSESSION (waits on event, times out cleanly,
  cancel-path returns instantly), signal handler installation, and
  that main and shutdown_state share the same Event instance.
2026-05-22 21:43:41 +03:00
..
2026-05-10 23:57:47 +03:00

LedGrab - Server

High-performance FastAPI server that captures screen content and controls WLED devices for ambient lighting.

Overview

The server component provides:

  • 🎯 Real-time Screen Capture - Multi-monitor support with configurable FPS
  • 🎨 Advanced Processing - Border pixel extraction with color correction
  • 🔧 Flexible Calibration - Map screen edges to any LED layout
  • 🌐 REST API - Complete control via 25+ REST endpoints
  • 💾 Persistent Storage - JSON-based device and configuration management
  • 📊 Metrics & Monitoring - Real-time FPS, status, and performance data

Quick Start

# Start server
docker-compose up -d

# View logs
docker-compose logs -f

# Stop server
docker-compose down

Server runs on: http://localhost:8080

Option 2: Python

# Create virtual environment
python -m venv venv

# Activate
source venv/bin/activate  # Linux/Mac
venv\Scripts\activate      # Windows

# Install dependencies
pip install .

# Set PYTHONPATH
export PYTHONPATH=$(pwd)/src  # Linux/Mac
set PYTHONPATH=%CD%\src       # Windows

# Run server
uvicorn ledgrab.main:app --host 0.0.0.0 --port 8080

Installation

Requirements

  • Python 3.11+ (for Python installation)
  • Docker & Docker Compose (for Docker installation)
  • WLED device on your network

See ../INSTALLATION.md for comprehensive installation guide.

Configuration

Configuration File

Edit config/default_config.yaml:

server:
  host: "0.0.0.0"
  port: 8080
  log_level: "INFO"

processing:
  default_fps: 30        # Target frames per second
  max_fps: 60           # Maximum allowed FPS
  border_width: 10      # Pixels to sample from edge

wled:
  timeout: 5            # Connection timeout (seconds)
  retry_attempts: 3     # Number of retries

storage:
  devices_file: "data/devices.json"

logging:
  format: "json"
  file: "logs/ledgrab.log"

Environment Variables

# Server configuration
export LEDGRAB_SERVER__HOST="0.0.0.0"
export LEDGRAB_SERVER__PORT=8080
export LEDGRAB_SERVER__LOG_LEVEL="INFO"

# Processing configuration
export LEDGRAB_PROCESSING__DEFAULT_FPS=30
export LEDGRAB_PROCESSING__BORDER_WIDTH=10

# WLED configuration
export WLED_WLED__TIMEOUT=5

Usage

WLED Device Setup

Important: Configure your WLED device using the official WLED web interface before connecting it to this controller:

  1. Access WLED Interface: Open http://[wled-ip] in your browser
  2. Configure Device Settings:
    • Set LED count and type
    • Configure brightness, color order, and power limits
    • Set up segments if needed
    • Configure effects and presets

This controller only sends pixel color data - it does not manage WLED settings like brightness, effects, or segments. All WLED device configuration should be done through the official WLED interface.

API Documentation

Quick Example

# 1. Add device
curl -X POST http://localhost:8080/api/v1/devices \
  -H "Content-Type: application/json" \
  -d '{"name":"Living Room","url":"http://192.168.1.100","led_count":150}'

# 2. Start processing
curl -X POST http://localhost:8080/api/v1/devices/{device_id}/start

# 3. Check status
curl http://localhost:8080/api/v1/devices/{device_id}/state

Testing

# Run all tests
pytest

# Run with coverage
pytest --cov=ledgrab --cov-report=html

# Run specific test
pytest tests/test_screen_capture.py -v

Development

Project Structure

src/ledgrab/
├── main.py              # FastAPI application
├── config.py            # Configuration
├── api/                 # API routes
├── core/                # Core functionality
│   ├── screen_capture.py
│   ├── wled_client.py
│   ├── calibration.py
│   └── processor_manager.py
├── storage/             # Data persistence
└── utils/               # Utilities

Code Quality

# Format code
black src/ tests/

# Lint code
ruff check src/ tests/

License

MIT - see ../LICENSE

Support