update-manager/docs/architecture.md

🧠 Update Manager Architecture

This document describes how Update Manager is structured internally and how data flows through the system.

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Overview

Update Manager is a lightweight, SSH-based system for managing updates across multiple Linux hosts.

It consists of two main layers:

• UI layer – interactive menu (update-manager-ui.sh)
• Core engine – update logic (update-manager.sh)

The system is designed to be simple, transparent, and dependency-light.

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High-Level Flow

User
  ↓
UI (update-manager-ui.sh)
  ↓
Core (update-manager.sh)
  ↓
SSH → Remote Hosts
  ↓
Results
  ↓
Logging (/opt/update-manager/log)
  ↓
UI / User

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Components

UI Layer (update-manager-ui.sh)

Responsible for:

• Displaying menu (via dialog)
• Handling user input
• Managing hosts (add/remove/edit)
• Providing access to logs
• Delegating actions to core engine

The UI does not perform updates directly.

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Core Engine (update-manager.sh)

Responsible for:

• Reading configuration
• Parsing hosts file
• Executing SSH commands
• Checking for updates (apt list --upgradable)
• Handling connection errors
• Writing structured logs

This is the execution layer of the system.

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Hosts Configuration

File:

/opt/update-manager/hosts.conf

Format:

name    ip    user

Example:

server1       192.168.1.10    user
server2       192.168.1.20    user
server3       192.168.1.30    user

Each line represents a target system accessed via SSH.

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Logging System

Log file:

/opt/update-manager/log/update-manager.log

Log format:

YYYY-MM-DD HH:MM:SS [LEVEL] host - message

Example:

2026-03-18 20:45:01 [INFO] lanx-www - Checking updates
2026-03-18 20:45:03 [OK] lanx-www - 3 updates available
2026-03-18 20:45:05 [ERR] lanx-db - Connection failed

Log Levels

• INFO – informational messages
• OK – successful operations
• ERR – errors or failures

Logging is centralized and written locally.

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Execution Flow

For each host:

1. Read host entry from hosts.conf
2. Establish SSH connection
3. Execute:

apt list --upgradable

4. Parse output

5. Determine:

   • Up-to-date
   • Updates available
   • Connection failure

6. Write result to:

   • terminal output
   • log file

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Configuration

Primary config:

/etc/update-manager.conf

Fallback:

./update-manager.conf

Supported options:

• HOSTS_FILE
• SSH_OPTIONS

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Design Principles

• No agents – uses standard SSH only
• Simple over complex – minimal dependencies
• Transparent behavior – everything is visible/logged
• CLI-first – designed for terminal environments
• Modular growth – prepared for future extensions

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Future Architecture Direction

Planned extensions:

• Plugin system (modular features)
• Web interface (optional UI layer)
• Notification system (alerts)
• Metrics / monitoring
• Integration with Lanx AI

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Summary

Update Manager follows a clean separation:

• UI = interaction
• Core = execution
• Config = data
• Log = output

This keeps the system predictable, debuggable, and easy to extend.