Show HN: Nupst v5 –> Deno based shutdown tool protecting against power outage

3 hours ago 1

Keep your systems safe when the power goes out. NUPST is a lightweight, battle-tested command-line tool that monitors SNMP-enabled UPS devices and orchestrates graceful system shutdowns during power emergencies. Distributed as self-contained binaries with zero runtime dependencies for maximum reliability.

Version 5.0+ is powered by Deno and distributed as single pre-compiled binaries—no installation, no setup, just run.

✨ Features

🔌 Multi-UPS Support: Monitor multiple UPS devices from a single installation
👥 Group Management: Organize UPS devices into groups with flexible operating modes
- Redundant Mode: Only shutdown when ALL UPS devices in a group are critical
- Non-Redundant Mode: Shutdown when ANY UPS device in a group is critical
⚙️ Action System: Define custom actions with flexible trigger conditions
- Battery threshold triggers
- Runtime threshold triggers
- Power status change triggers
- Configurable shutdown delays
🌐 Universal SNMP Support: Full support for SNMP v1, v2c, and v3 with authentication and encryption
🏭 Multiple UPS Brands: Works with CyberPower, APC, Eaton, TrippLite, Liebert/Vertiv, and custom OID configurations
🚀 Systemd Integration: Simple service installation and management
📊 Real-time Monitoring: Live status updates with detailed action and group information
🌐 HTTP API: Optional HTTP server for JSON status export with authentication
⚡ Power Metrics: Monitor output load, power (watts), voltage, and current for all UPS devices
📦 Self-Contained Binary: Single executable with zero runtime dependencies—just download and run
🖥️ Cross-Platform: Binaries available for Linux (x64, ARM64), macOS (Intel, Apple Silicon), and Windows

🚀 Quick Start

One-Line Installation

Initial Setup

That's it! Your system is now protected. 🛡️

📥 Installation

Automated Installer Script (Recommended)

The installer script handles everything automatically:

What it does:

Detects your platform (OS and architecture)
Downloads the latest pre-compiled binary
Installs to /opt/nupst/nupst
Creates symlink at /usr/local/bin/nupst
Preserves existing configuration

Installer Options

Manual Installation

Download the appropriate binary for your platform from releases:

Platform Binary

Linux x64	nupst-linux-x64
Linux ARM64	nupst-linux-arm64
macOS Intel	nupst-macos-x64
macOS Apple Silicon	nupst-macos-arm64
Windows x64	nupst-windows-x64.exe

Alternative: Via npm

Alternatively, NUPST can be installed via npm:

Note: This method downloads the appropriate pre-compiled binary for your platform during installation.

Verify Installation

📖 Usage

Command Structure

NUPST uses an intuitive subcommand structure:

Service Management

UPS Device Management

Group Management

Action Management 🆕

Actions define what happens when UPS conditions are met. Actions can be attached to individual UPS devices or to groups.

Example: Adding an action

Feature Management 🆕

Optional features like the HTTP server for JSON status export:

Example: Enabling HTTP Server

Query UPS Status via HTTP:

JSON Response:

Configuration

Global Options

⚙️ Configuration

NUPST stores configuration at /etc/nupst/config.json. The easiest way to configure is through interactive commands, but you can also edit the JSON directly.

Example Configuration (v4.1+)

Configuration Fields

Global Settings

version: Config format version (current: "4.2")
checkInterval: Polling interval in milliseconds (default: 30000)
httpServer: Optional HTTP server configuration (see HTTP Server Configuration below)

UPS Device Settings

id: Unique identifier for the UPS
name: Friendly name
groups: Array of group IDs this UPS belongs to
actions: Array of action configurations (see Actions section)

SNMP Configuration:

Field Description Values

host	IP address or hostname	e.g., "192.168.1.100"
port	SNMP port	Default: 161
version	SNMP version	1, 2, or 3
timeout	Timeout in milliseconds	Default: 5000
upsModel	UPS brand/model	'cyberpower', 'apc', 'eaton', 'tripplite', 'liebert', 'custom'
community	SNMP community (v1/v2c)	Default: "public"

SNMPv3 Security:

Field Description

securityLevel	'noAuthNoPriv', 'authNoPriv', or 'authPriv'
username	SNMPv3 username
authProtocol	'MD5' or 'SHA'
authKey	Authentication password
privProtocol	'DES' or 'AES' (for authPriv)
privKey	Privacy/encryption password

Action Configuration

Actions define automated responses to UPS conditions:

Action Fields:

Field Description Values

type	Action type	Currently only 'shutdown'
thresholds	Battery and runtime limits	{ battery: 0-100, runtime: minutes }
triggerMode	When to trigger action	See Trigger Modes below
shutdownDelay	Delay before executing (seconds)	Default: 5

Trigger Modes:

Mode Description

onlyPowerChanges	Trigger only when power status changes (on battery → online or vice versa)
onlyThresholds	Trigger only when battery or runtime thresholds are violated
powerChangesAndThresholds	Trigger only when power changes AND thresholds are violated
anyChange	Trigger on any status change

Group Settings

Groups allow coordinated management of multiple UPS devices:

Group Modes:

redundant: System shuts down only when ALL UPS devices in the group are critical. Perfect for setups with backup UPS units.
nonRedundant: System shuts down when ANY UPS device in the group is critical. Used when all UPS devices must be operational.

HTTP Server Configuration 🆕

Enable optional HTTP server for JSON status export with authentication:

HTTP Server Fields:

Field Description Default

enabled	Whether HTTP server is enabled	false
port	TCP port for HTTP server	8080
path	URL path for status endpoint	/ups-status
authToken	Authentication token (required for all requests)	Auto-generated

Authentication Methods:

The HTTP server supports two authentication methods:

Bearer Token (Header): Authorization: Bearer <token>
Query Parameter: ?token=<token>

Security Features:

Token-based authentication required for all requests
Returns 401 Unauthorized for invalid/missing tokens
Serves cached data from monitoring loop (no extra SNMP queries)
No CORS headers (local network only)

Use Cases:

Integration with monitoring systems (Prometheus, Grafana, etc.)
Custom dashboards and visualizations
Mobile apps and web interfaces
Home automation systems

Supported UPS Models

NUPST includes built-in OID mappings for:

CyberPower (cyberpower)
APC (apc)
Eaton (eaton)
TrippLite (tripplite)
Liebert/Vertiv (liebert)
Custom OIDs (custom)

For custom UPS models, specify customOIDs:

🖥️ Monitoring

Status Display

The status command shows comprehensive information about your UPS devices, groups, and configured actions:

Live Logs

Monitor NUPST in real-time:

Example output:

🔒 Security

NUPST is designed with security as a priority:

Architecture Security

Single Binary: Self-contained executable with zero runtime dependencies
No Installation Required: Pre-compiled binaries run immediately without package managers
Minimal Attack Surface: Compiled Deno binary with only essential SNMP functionality
Reduced Supply Chain Risk: Pre-compiled binaries with SHA256 checksums
Isolated Execution: Runs with minimal required privileges

SNMP Security

Full SNMPv3 support with authentication and encryption:

Security Level Description

noAuthNoPriv	No authentication, no encryption (not recommended)
authNoPriv	MD5/SHA authentication without encryption
authPriv	Full authentication + DES/AES encryption (recommended)

Example SNMPv3 Configuration:

Network Security

Local-Only Communication: Only connects to UPS devices on local network
No Telemetry: No data sent to external servers
No Auto-Updates: Manual update process only
HTTP Server (optional):
- Disabled by default
- Token-based authentication required
- Local network access only (no CORS)
- Serves cached data (no additional SNMP queries)
- Configurable port and path

Verifying Downloads

All releases include SHA256 checksums:

🔄 Updating NUPST

Automatic Update

Re-run the installer to update to the latest version:

The installer will:

Download the latest binary
Replace the existing installation
Preserve your configuration
Restart the service if it was running

Manual Update

Check for Updates

Visit the releases page for the latest version.

🗑️ Uninstallation

🔧 Troubleshooting

Binary Won't Execute

Service Won't Start

Can't Connect to UPS

Permission Denied Errors

Most system operations require root:

Action Not Triggering

📊 System Changes

When installed, NUPST makes the following changes:

File System

Path Description

/opt/nupst/nupst	Pre-compiled binary
/usr/local/bin/nupst	Symlink to binary
/etc/nupst/config.json	Configuration file
/etc/systemd/system/nupst.service	Systemd service unit

Services

Creates nupst.service systemd unit (when enabled)
Runs with root permissions (required for system shutdown)

Network

Outbound SNMP to UPS devices (default port 161)
Optional inbound HTTP server (disabled by default, configurable port)
No external internet connections

🚀 Migration from v3.x

Upgrading from NUPST v3.x (Node.js) to v4.x (Deno) is seamless:

The installer automatically:

Detects v3.x installation
Stops the service
Replaces Node.js version with Deno binary
Migrates configuration (v4.0 → v4.1 format if needed)
Restarts the service

Key Changes in v4.x

Aspect v3.x v4.x

Runtime	Node.js + npm	Deno
Distribution	Git repo + npm install	Pre-compiled binaries
Runtime Dependencies	node_modules required	Zero (self-contained)
Size	~150MB (with node_modules)	~80MB (single binary)
Startup	Seconds	Milliseconds
Commands	Flat (nupst add)	Subcommands (nupst ups add)
Configuration	UPS-level thresholds	Action-based thresholds

Configuration Compatibility

Your v3.x configuration is fully compatible. The migration system automatically converts:

v4.0 format (UPS-level thresholds):

v4.1 format (action-based thresholds):

Migration happens automatically on first run—no manual changes needed.

💻 Development

Building from Source

Requirements: Deno v1.x or later

Project Structure

📞 Support

Issues: Report bugs or request features
Documentation: Full documentation
Source Code: View source

License and Legal Information

This repository contains open-source code that is licensed under the MIT License. A copy of the MIT License can be found in the license file within this repository.

Please note: The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.

Trademarks

This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH and are not included within the scope of the MIT license granted herein. Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines, and any usage must be approved in writing by Task Venture Capital GmbH.