9f3f346543
SystemMetricsValueStream used to dispatch on its ``self._metric`` string across three independent if/elif chains (audit finding M5): * priming in ``start()`` (cpu_percent seed, initial network counter); * raw reading in ``_read_metric_psutil`` plus ``_read_metric_fallback``; * normalisation in ``_normalize`` (percent / min-max range / max-rate). Adding a new metric meant editing all three chains plus the Android fallback — and forgetting one branch made the metric silently return 0. Lift each per-metric concern into a free function and register them as a ``MetricSpec(name, read_psutil, read_fallback, normalize, prime)`` in a new ``core.processing.metric_readers`` module. Shared normalisers (``_norm_percent`` / ``_norm_range`` / ``_norm_rate`` / ``_zero``) live once. The stream's ``start()`` / ``_read_metric()`` / ``_normalize()`` collapse to a single registry lookup + delegation. The stream still owns its mutable state (``_disk_path``, ``_sensor_label``, ``_gpu_unavailable``, ``_prev_net_bytes``, ``_prev_net_time``, etc.) — readers operate on the stream by parameter, not by inheritance, so the kitchen-sink class shrinks by ~140 lines without losing the per-stream cadence bookkeeping. Each spec function's docstring documents which fields it reads or mutates. Tests: 16 new tests cover the 10-metric coverage set, callable shape of every spec field, the three normaliser primitives' clamping + divide-by-zero behaviour, prime-hook presence (only the three metrics that need a baseline: cpu_load + network_rx + network_tx), and fallback-path expectations (desktop-only sensors -> _zero, cpu/ram -> real MetricsProvider). 754 existing core / storage / api tests stay green; ruff clean.
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
Option 1: Docker (Recommended)
# 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:
- Access WLED Interface: Open
http://[wled-ip]in your browser - 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
- Web UI: http://localhost:8080 (recommended for device management)
- Swagger UI: http://localhost:8080/docs
- ReDoc: http://localhost:8080/redoc
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