Creating modules

Modules in MiniOS are self-contained packages of files and configurations that extend the functionality of the base system. They are similar to packages in other Linux distributions, but they are designed to be layered on top of each other, allowing for a flexible and customizable system. This layered approach enables easy customization, rollback of changes, and sharing of configurations.

There are quite a lot of utilities for creating modules in MiniOS. All of them are designed to use the terminal.

apt2sb - installs packages from repositories and packages them into a module. script2sb - performs the actions described in the script and packages the result into a module. chroot2sb - opens chroot, allowing you to perform any actions in it, after exiting it saves the result in the module.

apt2sb

To build a module using apt2sb, simply list the packages you want to package in the module, e.g. apt2sb install chromium chromium-sandbox. Running this command in the folder where the command was run will result in a chromium.sb module that will contain the Chromium browser. This module will be built relative to all the modules that are loaded into the system, which means that it will require all of them to run, since the libraries required for the program to work may already be installed in the system and may be contained in the lower modules.

Using the -l/--level option we can specify on which top module we need to build our module. For example, the apt2sb install -l 4 chromium chromium-sandbox command will filter out all modules numbered 04 and above when building, i.e. the module will be built based on modules numbered 00-03. As a result of executing this command, we will get the 04-chromium.sb module in the folder from which the command was executed. This module will have a larger size than the package in the previous example because it will include all the libraries necessary to run the program, which could be contained in modules with numbers 04 and higher, but it will be able to run both in the presence of modules with numbers 04-xx and in their absence.

The module name is created automatically, based on the name of the first specified package (in our case, chromium) and, if the --level option is specified, the level number. In case you want to specify the module name yourself, you can use the -n/--name option, e.g. apt2sb install -l 4 chromium chromium-sandbox -n 10-browser.sb.

apt2sb also has an upgrade command that allows to upgrade already installed packages.

script2sb

To build a module using script2sb, you need to write a bash script that describes the steps required to build your module. This can be useful if you need to perform some actions in the file system, import keys, add a repository, etc. before or after the installation. Here is an example of such a script:

#!/bin/bash
# Install the keys to access the Debian repository and the apt add-on to access the repository via https
apt install -y debian-keyring debian-archive-keyring apt-transport-https
# Adding a GPG key for the Caddy repository
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | gpg --dearmor -o /usr/share/keyrings/caddy-stable-archive-keyring.gpg
# Add the Caddy repository to the package source list
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' | tee /etc/apt/sources.list.d/caddy-stable.list
# Updating the list of packages
apt update
# Installing Caddy
apt install caddy
# Remove keys to access the Debian repository
apt remove -y debian-keyring debian-archive-keyring apt-transport-https
# Deleting the source list file and GPG key for the Caddy repository
rm /etc/apt/sources.list.d/caddy-stable.list /usr/share/keyrings/caddy-stable-archive-keyring.gpg

To run a build on this script (let's call it caddy.sh), you must run the script2sb -s ./caddy.sh command.

Additionally, you can add the -l/--level and -n/--name options to specify the module filter level and module name (see the apt2sb description for more details on the purpose of the module filter option). If no module name is specified, the name is created based on the level number, if specified, and the script name. An example of executing a command using these options is: script2sb -s ./caddy.sh -l 1 -n 01-caddy.sb.

In addition to these options, you can use the -d/--directory option. If this option is specified, the contents of the folder specified by the option argument will be copied to the root of the module before the script is executed. The files in such a folder should be arranged as they would be in the root folder of the system. Let's say you need to place a shortcut for some program in the menu, then let's create a mymodule folder and create a structure in it relative to the system root:

mkdir -p /home/user/mymodule/usr/share/applications

In the mymodule/usr/share/applications folder you should put the desktop file that will be packed into the module after the build is complete and run the build command:

script2sb -s ./caddy.sh -l 1 -n 01-caddy.sb -d /home/user/mymodule

chroot2sb

The chroot2sb utility is used to create an interactive chroot environment. This allows you to manually perform any actions required to build your module (install packages, edit files, run commands, etc.). Once you exit the chroot environment, the changes you made are packaged into a module.

As with apt2sb and script2sb, you can use the -l/--level and -n/--name options to specify the module filter level and module name (see the apt2sb description for more details). If no module name is specified, the name is created based on the level number, if specified, and the current date and time.

You can also use the -d/--directory option, similar to script2sb. If this option is specified, the contents of the specified folder will be copied to the root of the module before you enter the chroot environment. This provides a starting point for your customizations.

Example Usage:

• Basic chroot, automatic module name: chroot2sb
• Specify level and compression: chroot2sb -l 3 -c gzip
• Specify level, name, and compression: chroot2sb -l 3 -n 04-my-module.sb -c xz
• Copy files from a directory before entering chroot: chroot2sb -d /path/to/my/files

After running the chroot2sb command, you will be placed in a chroot environment. You can then perform any actions you need. When you're finished, type exit to leave the chroot environment. chroot2sb will then package the changes into a module. Any commands entered in the chroot are not saved as part of the final module's installation process. It's a snapshot of the final filesystem state. The history of bash is deleted.