Signifer

A signifer was a standard bearer of the Roman legions. He carried a signum (military standard) for a cohort or century.

Signifer is a network device monitoring application that tracks device availability via ICMP pings and sends Discord webhook notifications when status changes occur.

Features

• ICMP Monitoring: Ping devices (IPv4/IPv6) with configurable intervals
• State Tracking: Detects device status changes (online ↔ offline)
• Discord Notifications: Rich embeds with color coding, latency, and failure reasons
• Web UI: Device management interface powered by Templ and Tailwind CSS
• SQLite Database: Lightweight data persistence
• Basic Authentication: Secure web interface access

Quick Start

Docker (Recommended)

# Create config.yaml from example
cp config.yaml.example config.yaml
# Edit config.yaml and add your Discord webhook URL

docker-compose up -d

Access at http://localhost with credentials admin/admin.

From Binary

# Build
./build.sh

# Create config.yaml
cat > config.yaml << EOF
discord:
  webhook_url: "YOUR_DISCORD_WEBHOOK_URL"
EOF

# Run
./signifer

Configuration

Create a config.yaml file:

# Web server port (default: 9090)
port: 9090

# Discord webhook URL (REQUIRED)
discord:
  webhook_url: "https://discord.com/api/webhooks/YOUR_WEBHOOK_ID/YOUR_WEBHOOK_TOKEN"

# Basic authentication (default: admin/admin)
auth:
  user: "admin"
  password: "secure_password"

# Ping configuration
ping:
  interval_seconds: 30  # How often to ping devices (default: 30)

Using Docker

The config.yaml file is mounted into the container at /app/config.yaml. Create this file before running:

# Create config.yaml on host
cat > config.yaml << EOF
discord:
  webhook_url: "YOUR_DISCORD_WEBHOOK_URL"
EOF

# Run with docker-compose
docker-compose up -d

Discord Notifications

Signifer sends notifications when:

• A device goes offline (red embed)

  • Includes hostname, previous state, and reason (DNS resolution error, timeout, etc.)

• A device comes back online (green embed)

  • Includes hostname, previous state, current state, and latency

Example Notification

Device Offline:

┌─────────────────────────────────────────┐
│ Device Offline                          │
│ Database Server is no longer responding │
├─────────────────────────────────────────┤
│ Hostname:       db01.example.com        │
│ Previous State: Online                  │
│ Current State:  Offline                 │
│ Reason:         DNS resolution error    │
└─────────────────────────────────────────┘

Building from Source

Prerequisites

• Go 1.25+
• GCC (for SQLite)

Build

go build -o signifer .
sudo setcap cap_net_raw=+ep ./signifer  # Grant ICMP capability

Development

# Generate templ code
templ generate

# Generate SQL code
sqlc generate

# Run
go run .

License

MIT