# Systant

A comprehensive Elixir-based system monitoring solution with real-time dashboard, designed for deployment across multiple NixOS hosts.

## Components

- **Server** (`server/`): Elixir OTP application that collects and publishes system metrics via MQTT
- **Dashboard** (`dashboard/`): Phoenix LiveView web dashboard for real-time monitoring
- **Nix Integration**: Complete NixOS module and packaging for easy deployment

## Features

### System Metrics Collection
- **CPU**: Load averages (1/5/15min) and utilization monitoring
- **Memory**: System memory usage and swap monitoring  
- **Disk**: Usage statistics and capacity monitoring for all drives
- **System Alarms**: Real-time alerts for disk space, memory pressure, etc.
- **System Info**: Uptime, Erlang/OTP versions, scheduler information

### Real-time Dashboard
- Phoenix LiveView interface showing all connected hosts
- Live system metrics and alert monitoring
- Automatic reconnection and error handling

### MQTT Integration
- Publishes comprehensive system metrics every 30 seconds
- Uses hostname-based topics: `systant/${hostname}/stats`
- Structured JSON payloads with full system data
- Configurable MQTT broker connection

## Quick Start

### Development Environment
```bash
# Enter Nix development shell
nix develop

# Run the server
cd server && mix run --no-halt

# Run the dashboard (separate terminal)
just dashboard
# or: cd dashboard && mix phx.server
```

### Production Deployment (NixOS)
```bash
# Build and install via Nix
nix build
sudo nixos-rebuild switch --flake .

# Or use the NixOS module in your configuration:
# imports = [ ./path/to/systant/nix/nixos-module.nix ];
# services.systant.enable = true;
```

## Configuration

Default MQTT configuration (customizable via environment variables):
- **Host**: `mqtt.home:1883`
- **Topics**: `systant/${hostname}/stats` and `systant/${hostname}/commands`
- **Interval**: 30 seconds
- **Client ID**: `systant_${random}` (auto-generated to avoid conflicts)

## Architecture

- **Server**: `server/lib/systant/mqtt_client.ex` - MQTT publishing and command handling
- **Metrics**: `server/lib/systant/system_metrics.ex` - System data collection using `:os_mon`
- **Dashboard**: `dashboard/lib/dashboard/mqtt_subscriber.ex` - Real-time MQTT data consumption
- **Nix**: `nix/package.nix` and `nix/nixos-module.nix` - Complete packaging and deployment

## Roadmap

- ✅ **Phase 1**: System metrics collection with real-time dashboard
- 🔄 **Phase 2**: Command system for remote host management  
- 🔄 **Phase 3**: Home Assistant integration for automation

See `CLAUDE.md` for detailed development context and implementation notes.