#debug-tool #log #viewer

app logv

A very simple program to view and filter logs easily

4 releases

0.3.0 Feb 20, 2023
0.2.2 Mar 18, 2021
0.2.1 Mar 18, 2021
0.2.0 Mar 18, 2021

#37 in Visualization

MIT license

215 lines

Log viewer

A very simple program to view and filter logs easily. It's a crude, but efficient tool to view log files. Focuses on ease of installation and ease of use. Only one binary to drop somwhere in PATH and it will work anywhere there is a browser available. Easy for non-techical users to use.

Example GIF


After installation, write: logv in a root folder where you want to search and find log files in the subfolders.

The app transverses all subdirectories from where it's called and looks for *.log files. These files are all parsed and categorized by the keywords:

  • INFO
  • WARN

Lines that doesn't match any of these are categorized as "other".

The app will launch a local webserver and open a UI in the default web browser.

This is a small program that should be pretty easy to audit and look through. It only implements the bare minimum of functionality, and is especially geared towards typical log output from Rust programs.

Close the console program when you're done by closing the console window or Ctrl + C.

Goals and pros/cons

This is a crude tool with only some advantages:

  • Easy to install. Just build and drop in PATH (or cargo install) and that's it
  • Small program size
  • Short codebase, easy to audit and review (for those that doesn't like to run arbitrary programs in certain environments, this program probably takes 20 minutes to audit)
  • Easy to adapt and extend to you own needs
  • Easy to contribute to the codebase

This is not the most efficient, the most featurefull or the most advanced log viewer available. It was built with the advantages above in mind and for my own use.

Large files

There is no paging so rendering very large files will take a lot of resources.



cargo install logv

Or download the source code, build with cargo build --release and drop the resulting binary somewhere in "PATH" so you can call it in a project directory from the command line.

Technical details

The Rust program is only 260 lines of code and the UI is 320 lines of HTML/JavaScript.

The search logic is written using only the Rust strandard libray, and the UI is written using only vanilla JavaScript. Besides that the dependencies are as follows.

  • Rocket is used as the web server.
  • Serde is used for serialization
  • Bootstrap is used as the frontend toolkit


Only tested in Windows, but should work on any fully supported Rust target where a web browser is available.


~887K SLoC