LogViewer

A real-time log viewer built with Qt 6 and C++17.

Features

• Real-time tailing via QFileSystemWatcher — updates as the file grows
• Auto-detect structured vs plain text log lines
• Level filtering — toggle DEBUG / INFO / WARN / ERROR / FATAL independently
• Text search — live filter across all messages
• Color-coded rows per log level
• Auto-scroll toggle
• Log rotation handling — detects when a file is truncated/replaced
• Dark theme via Fusion style + custom palette

Structured Log Format

The parser recognizes lines matching:

[LEVEL] HH:mm:ss - message
[LEVEL] yyyy-MM-dd HH:mm:ss - message

Examples:

[INFO]  12:00:01 - Server started on port 8080
[WARN]  12:00:05 - High memory usage detected
[ERROR] 12:00:09 - Failed to connect to database
[DEBUG] 12:00:10 - Packet received: 42 bytes
[FATAL] 12:00:11 - Unhandled exception, shutting down

Any line that doesn't match is treated as plain text and shown with level PLAIN.

Build

Requirements

• Qt 6.x (Core, Widgets)
• CMake 3.16+
• C++17 compiler

Steps

cmake -S . -B build
cmake --build build
./build/LogViewer

Architecture

File	Responsibility
LogEntry.h	Plain data struct — level, timestamp, message, raw line
LogParser	Stateless parser — structured regex + plain text fallback
LogWatcher	QFileSystemWatcher wrapper — emits newLines signal
LogModel	QAbstractTableModel — owns log entries, drives the view
LogFilterProxyModel	QSortFilterProxyModel — level + text filtering
MainWindow	Top-level UI — toolbar, table, status bar, dark theme