# uptimetracker

A lightweight HTTP uptime monitor written in Go. Checks a list of URLs at a configurable interval, logs results, and sends Discord alerts on state changes.

## Features

- Checks multiple targets concurrently
- Alerts on DOWN and recovery via Discord webhook (fires once per state change, no spam)
- Logs to file and stdout simultaneously

## Configuration

Edit `config.json`:

```json
{
  "interval_seconds": 30,
  "discord_webhook": "https://discord.com/api/webhooks/...",
  "log_file": "uptimetracker.log",
  "targets": [
    { "name": "My Site", "url": "https://example.com" }
  ]
}
```

| Field | Required | Description |
|---|---|---|
| `targets` | yes | List of sites to monitor |
| `interval_seconds` | no | Check frequency, defaults to 60 |
| `discord_webhook` | no | Discord webhook URL for alerts |
| `log_file` | no | Log file path, defaults to `uptimetracker.log` |

## Usage

```bash
go build -o uptimetracker .
./uptimetracker             # uses config.json in current directory
./uptimetracker /path/to/config.json
```

Output:

```
2026-02-25 18:00:00  started monitoring 1 target(s) every 30s
2026-02-25 18:00:00  My Site  UP    200  45ms
2026-02-25 18:00:30  My Site  DOWN  503  120ms
2026-02-25 18:00:30  alert sent: My Site is DOWN
```

## Deploy with systemd

Build a Linux binary:

```bash
GOOS=linux GOARCH=amd64 go build -o uptimetracker .
```

Copy to your server:

```bash
scp uptimetracker config.json uptimetracker.service user@your-vps:~/uptimetracker/
```

Install and start the service:

```bash
# Update User= and paths in the service file to match your username
sudo cp ~/uptimetracker/uptimetracker.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now uptimetracker
```

View logs:

```bash
sudo journalctl -fu uptimetracker
```