LogParser (C++ / Qt 6)

A lightweight but powerful log viewer written in C++17 with Qt 6.

Parses lines into columns and filters on a per-column basis, both using regex for maximal flexibility.

For messages containing JSON data, a separate dialog allows the user to format the json and use JSONPath style filtering of the data.

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✨ Features

• Multi‑tab live tailing (create tabs with Ctrl+T)
• Two parsing modes
  • py_logging_fmt → converts %(asctime)s %(levelname)s … %(message)s to a regex, easy to copy-paste directly from your python logging setup
  • regex → your named-group pattern (e.g., (?<asctime>...) (?<levelname>...) (?<message>.*)) for full flexibility
• Dynamic table columns with level-based coloring
• Per‑column regex filters + time‑range filter on asctime
• Time-aware sorting (true chronological sort by asctime)
• Unread badges on tabs using colored dot icons (green dot = new activity, red dot = new error) for easy overview when using multiple tabs
• “First new row” when switching to another tab, a green line within the table will show the user what lines are unread/new
• Copy multiple selected cells to clipboard with Ctrl+C
• Message dialog by double-clicking a message
  • shows full message, practical for very long messages
  • Pretty JSON formatting + Text search/highlight
  • Auto-detect embedded JSON fragments inside text
  • Foldable JSON tree view
  • Mini JSONPath: $['key'][0]['nested'] to view subsets of the json data

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🚀 Building

This repo ships with CMake Presets. You can configure & build with one line.

Prerequisites

• Qt 6.10.2 installed
  • MinGW kit: (e.g. C:/Qt/6.10.2/mingw_64) added to QT_ROOT
  • MinGW toolchain: (e.g. C:/Qt/Tools/mingw1310_64/bin) added to PATH
• CMake 3.21+

Configure & build (MinGW, Release)

cmake --preset mingw-release
cmake --build --preset mingw-release -j

Configure & build (MinGW, Debug)

cmake --preset mingw-debug
cmake --build --preset mingw-debug -j

Feel free to use the run_build.bat script to build and install. Just make sure to edit the paths inside to your local Qt installation.

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▶️ Run

From the build folder:

.\build\mingw-release\log_parser.exe

Run with one or more files to open them directly:

.\log_parser.exe C:\logs\app.log C:\logs\server.txt

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📦 Install / Deploy

This project uses Qt’s qt_generate_deploy_app_script(...). After building:

cmake --install build\mingw-release

You’ll get a self-contained folder (Qt DLLs/plugins are copied) at:

install\mingw-release\bin\log_parser.exe

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🧑‍💻 Usage quick‑start

• Choose file → Reload All to load the full file, Start to tail for live updates.
• Apply Format with py_logging_fmt or regex to parse columns. The column asctime enables time filters & chronological sorting.
• Type regex in any column filter field (invalid patterns are tinted red).
• Enable Use From/To to filter by time.
• Double-click a row for the message dialog popup:
  • Enter free form text in the search bar to highlight text
  • If the message contains (but not necessarily solely) a JSON, enter $['key'][0]['anotherkey'] in the JSON filter to view a subtree.