Here are some quick notes I put together over the last few months about navigating the uncharted waters of legacy projects. Generally, I think any code that isn’t actively worked on or tested can be considered legacy. The discovery refers to the process of getting to know code that isn’t well understood – for example when onboarding on a new project that has poor documentation.

Generally, I like to start by looking at the code at a very high level. You can only learn so much from this, but it’s usually an automated quick step that gives some insight.

Code overview

Gource

Gource will give you a good amount of information on how the project has been worked on in the past – who maintains what parts of it, how frequently, as well as what the project is made of.

Sample command, piping the video to ffmpeg for storage:

gource -s 0.05 -1280x720 --stop-at-end --key --highlight-users --hide mouse,progress --file-idle-time 0 --max-files 0 --background-colour 000000 --font-size 22 --title "my gource" --output-framerate 30 -o - | ffmpeg -y -r 30 -f image2pipe -vcodec ppm -i - -vcodec libx264 -preset ultrafast -pix_fmt yuv420p -crf 1 -threads 0 -bf 0 gource.mp4

Requirements: ffmpeg. Then use VLC for compression. Share the output around, it’s always interesting to look at.

tree and cloc

tree and cloc are two useful CLI tools that will give you lots of insight into the contents of a project in a short amount of time. Do learn what options are available for both of them.

tree -D -L 2 .

cloc --vcs git .

eralchemy

eralchemy -i 'mysql://root:<pw>@127.0.0.1/my_db' -o output.pdf
eralchemy -i 'mysql://root:<pw>@127.0.0.1/my_db' -o output.er