truckfactor 0.2.2

Tool to compute the truck factor of a Git repository

What is this?

This tool, truckfactor computes the truck (bus/lorry/lottery) factor for a given Git repository.

The truck factor is

the number of people on your team that have to be hit by a truck (or quit) before the project is in serious trouble

L. Williams and R. Kessler, Pair Programming Illuminated. Addison Wesley, 2003.

One of the earliest occurrences of the term in a real project was in the Python mailing list: "If Guido was hit by a bus?"

Installation

pip install truckfactor

Requirements

The tool requires that git is installed and accessible on PATH.

How to use it?

You have to either point the tool to a directory containing a Git repository or to a URL with a remote repository. In case a URL is given, the tool will clone the repository into a temporary directory.

From the terminal, the tool can be run as in the following:

$ truckfactor <path_or_url_to_repository>
The truck factor of <path_to_repository> is: <number>

For now, it just returns one line of text ending in the number of the truck factor for that repository.

Calling it from code:

from truckfactor.compute import main


truckfactor = main("<path_to_repo>")

How does the tool compute the truck factor?

In essence the tool does the following:

• Reads a git log from the repository
• Computes for each file who has the knowledge ownership of it.
  • A contributor has knowledge ownership of a file when she edited the most lines in it.
  • That computation is inspired by A. Thornhill Your Code as a Crime Scene.
  • Note, only for text files knowledge ownership is computed. The tool may not return a good answer for repositories containing only binary files.
• Then similar to G. Avelino et al. A novel approach for estimating Truck Factors low-contributing authors are removed from the analysis as long as still more than half of all files have a knowledge owner. The amount of remaining knowledge owners is the truck factor of the given repository.