`screen-compose`

It's like docker compose, but instead of containers in Docker, it's command shells in GNU Screen.

david@carbon:~/src/screen-compose$ ./screen-compose example
david@carbon:~/src/screen-compose$ screen -list
There is a screen on:
        55734..carbon   (06/15/2024 02:09:26 AM)        (Detached)
1 Socket in /run/screen/S-david.
david@carbon:~/src/screen-compose$ screen -r

Now you're attached to a screen session that's running all of the shells defined in the example.

You can even run screen-compose as a @reboot cron user job, and attach to it later over ssh. That's the idea.

Why

I have various websites, side projects, and home automation programs running on an old laptop that I use as a home server. Whenever that server reboots, I have to remember what was running on it.

There are many solutions to this problem, but I want one that feels as close as possible to me setting things up by hand every time. I want to automate opening up a bunch of shells and typing commands into them.

What

screen-compose is a Python script that reads a configuration file and then executes screen in detached mode. The configuration file specifies how many windows the screen session will have, their titles, and initial shell commands to type into each window.

The configuration file format is described in the example configuration.

How

david@carbon:~/src/screen-compose$ ./screen-compose --help
usage: screen-compose [-h] [-S SESSION_NAME] [--lint] config_file

Set up a GNU Screen session.

positional arguments:
  config_file           path to configuration file

options:
  -h, --help            show this help message and exit
  -S SESSION_NAME, --session-name SESSION_NAME
                        custom name for the session
  --lint                validate configuration without running GNU screen

david@carbon:~/src/screen-compose$ ./screen-compose ./example
david@carbon:~/src/screen-compose$ screen -r

python read.py
python read.py
python read.py
python read.py
python read.py








 [0 asus probe]  1 lookatmyplants.com f  2 fowzystuff.com mover  3 shell

One way to have it run on boot:

david@denmark:~$ crontab -l | grep '@reboot'
@reboot         cd ~/src/screen-compose && ./screen-compose --session-name services ./services >>log 2>&1
david@denmark:~$

Why not systemd?

I don't want to use service, systemctl, and journalctl to manage my pet projects. I want to get in there with my hands and poke around with a shell.

Why not docker compose?

I don't want to use docker compose {attach,exec,logs} to manage my pet projects. I want the scripts and services to run on the system outside of any container.

Why not GNU Shepherd?

I just want to automate setting up a screen session, ok?

How does it work?

When GNU Screen starts, it reads a file of commands. By default it reads ~/.screenrc, but the file path can be overridden via the -c command line option.

screen-compose creates such a file and passes it to screen. One file is not enough, though, because in order to reliably execute large amounts of shell commands in a screen window, the commands must be read from a separate file. So, screen-compose creates a temporary directory containing multiple files, executes screen, and later deletes the temporary directory.

dgoffredo/screen-compose