Git Commits: Year In Review

A few years ago I saw someone post a video they created by capturing a picture from their webcam each day and then combining them together into a movie. I was struck by how interesting it was to watch small changes in a person over time. So I thought I would try to do something similar.

Unfortunately, I knew there was no way I could remember to take a picture every day. Even if I could, it would quickly become one more task to complete in my already packed days. I needed a way to automate the process.

A bit later I learned about Git Hooks and saw someone using git hooks to take a webcam picture. (I unfortunately cannot remember where I first saw this or I would credit them..)

A git commits timeline.

I created a post-commit git hook that would take a picture with the built in webcam immediately after each commit. It's as simple as creating a file inside your project's .git/hooks directory named post-commit. Chances are, there are some samples already in that directory.

Inside the post-commit file paste this snippet:

#!/usr/bin/env ruby
puts "Taking capture into #{file}!"
system "imagesnap -q -w 3 #{file}"
exit 0

Lines 2, 3 and 4 are the ones we need to focus on.

Line #2 defines where the new image will be saved. I use a Dropbox folder for this which allows me to work from multiple machines and have all git shots saved together. The #{} bit creates a file name based on the current time. This makes sure that each file has a unique name and is easily kept in the correct order.

Line #3 prints a message to the console with the file name each time the script runs.

Line #4 takes the actual picture and saves it to the path and filename that was defined in line #2.

Creating a movie or Gif.

If you want to create a movie or gif from your gitshots, you will need to install ImageMagick. ImageMagick is a powerful image editing and transformation tool that offers us some command line functionality.

If you are a homebrew user, simply brew install:

brew install imagemagick

Once ImageMagick is installed, navigate into your gitshots directory and run this command:

convert -quality 100 -delay 30 *.jpg _myGifName.gif

Or for a movie:

convert -quality 100 -delay 30 *.jpg _myMovieName.mp4

This will run a conversion with the quality set to 100 with a delay of 30 ticks per second between each image. Every JPG in the current directory will be used and the output file will be saved in the same directory with the name _movie.mp4.

Note: In my own tests the video always seems to have a render error about 4/5 of the way through. I've tried using fewer images or lowering the quality with no luck. If any of you know the reason, I'd love to know why!

Automate the post-commit creation.

Copying our new post-commit file into every new repo will become tiresome very quickly. Luckily Git allows us to create templates that all new git repos will be initialized with.

Templates for git hooks live in ~/.git_template/hooks/. Simply drop in your post-commit file and the next time git init is run in a directory, the git repo will include this post commit function.

The finished product

Since the video creation wouldn't work, here is a sample Gif.

Gitshots Year In Review

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Benjamin Charity

Self-motivated UXE technical lead focused on building highly scalable systems for both the web and mobile platforms. Currently focused on Design Language Systems and Component Libraries.