How to save and restore your programs when using i3

6 April 2024

Introduction

One of the oldest problems I run into with Operating Systems in general, the lower layer of my development environment, is saving/managing my workspace.
But what does “workspace saving” mean exactly, what am I trying to achieve here?

I don’t want my OS to be able to restore my windows when I restart, it’s not about that, I can deal with this problem by not rebooting. What I want is the ability to to close apps and programs in order to have a clean workspace that contains only what I need at the moment. I also want to be able to reopen group of windows at will, to me, these group of windows basically mean the same as a projet. That’s right, a group of windows and their states is a project.

So how would you go about achieving this? These are the solutions I was able to find :

Using a (autonomous) solution that means :

A full-fledged IDE (other than VSCode)
Paid software at the OS-level (on Windows for the most part)

Scripting

That is what I will be writing about.

How to achieve workspace switching at the os-layer through scripting

The first thing I have to think about is the usage. I want, through a script, command or whatever, be able to open a specific workspace. Something like workspace.sh [project] [feature] for example.

I have to make a clear distinction between the project and the feature.

The project is in this case would represent the framework, the basis : the i3 layout, the setup scripts and the programs/scripts themselves. The feature could be a specific branch in a git repository for example, or it could be as simple as a parameter that you give to your programs/scripts.

Use case

Let’s say I want to work on a project called foo, on very this project I work simultaneously on 3 separate features. The first thing would be that I want to have one terminal, right where the project lives. I also want the shell session to start some init. scripts, that could be something like a Python venv for example. If I’m working on a Web application I would also need my browser opened up.

Scripting

Prerequisites

i3
i3-resurrect
dmenu

Scripts

Prompt the user for the project it wants to work on.
Run the main.sh script for the selected project

The script might prompt the user for additional information such as the feature.

workspace.sh

#!/usr/bin/env sh

projects_path="$HOME/.i3/i3-resurrect/projects"

project_name=$(ls "$projects_path" | dmenu -p project  -i | xargs)

if [[ "$project_name" == "" ]]; then
  echo "Invalid project"
  exit 1
fi

project_path="$projects_path/$project_name"
temp_folder="$(mktemp -d)"
workspace_number=$(i3-msg -t get_workspaces   | jq '.[] | select(.focused==true).name'   | cut -d"\"" -f2)
$project_path/main.sh "$project_path" "$temp_folder" "$workspace_number" && pipx run i3-resurrect restore -d "$temp_folder" -p current
rm -rf "$temp_folder"

main.sh

#!/usr/bin/env sh
project_path="$1"
temp_folder="$2"
workspace_number="$3"
feature_name=$(ls -t /my_project_path/.features | dmenu -p Feature -i | xargs)
if [[ "$feature_name" == "" ]]; then
  echo "Invalid feature_name"
  exit 1
fi
mkdir $temp_folder/profiles
sed -e "s/%{feature_name}/$feature_name/g" "$project_path/programs.json" > "$temp_folder/profiles/current_programs.json" && \ 
sed -e "s/%{feature_name}/$feature_name/g" "$project_path/layout.json" > "$temp_folder/profiles/current_layout.json"

programs.json

See https://github.com/JonnyHaystack/i3-resurrect

vscode
firefox
2 xterm windows

[
  {
    "command": [
      "/opt/visual-studio-code/code",
      "/my_project_path/.features/%{feature_name}/%{feature_name}.code-workspace"
    ],
    "working_directory": "/my_project_path/.features/%{feature_name}"
  },
  {
    "command": [
      "/usr/lib/firefox/firefox"
    ],
    "working_directory": "$HOME"
  },
  {
    "command": [
      "/usr/bin/xterm",
			"-class",
      "UXTerm",
      "-u8",
      "-bw",
      "0",
      "-e",
      "bash --login -i <<< 'source /home/user/.venvs/project/%{feature_name}/bin/activate; exec </dev/tty'"
    ],
    "working_directory": "$HOME"
  },
  {
    "command": [
      "/usr/bin/xterm",
			"-class",
      "UXTerm",
      "-u8",
      "-bw",
      "0",
      "-e",
      "bash --login -i <<< 'source /home/user/.venvs/project/%{feature_name}/bin/activate; exec </dev/tty'"
    ],
    "working_directory": "$HOME"
  }
]

layout.json

After setting up your layout manually you can save it using i3 (see https://i3wm.org/docs/layout-saving.html) or i3-ressurect (see https://github.com/JonnyHaystack/i3-resurrect?tab=readme-ov-file#usage)

That’s about it, now you can save and restore your workspaces.

Thanks for reading.