SNAP Tutorial 01. What is a snap and a simple example of a package assembly

snap

Hello everyone.

It has long been planned to write a couple of articles on the topic of assembling self-contained snap packages.

If anyone does not know, then the snapcraft technology is a package assembly similar to * .deb or * .rpm. But for a slight difference, the snap package is completely self-contained. That is, he does not need anything from the system at all. At the moment snap packages support such distributions as Arch, Debian, Fedora, Gentoo and itself the progenitor of this technology Ubuntu. There are about 5-6 distributions that support, but I did not check them. On the forums write that it works)).

In this article I will describe a little the configuration file for the assembly.

In order to compile a snap package, it is required to have snapd and snapcraft installed on the system.

1. snapd - The utility for working with the installation and managing the finished packages.
2. snapcraft - A utility to build your application into a snap package.

After you install everything you need to create a directory for our work, and in it a file snapcraft.yaml or in the console snapcraft init and then we get the default file in the snap directory which will look like this:

name: my-snap-name # you probably want to 'snapcraft register <name>'
version: '0.1' # just for humans, typically '1.2+git' or '1.3.2'
summary: Single-line elevator pitch for your amazing snap # 79 char long summary
description: |
This is my-snap's description. You have a paragraph or two to tell the
most important story about your snap. Keep it under 100 words though,
we live in tweetspace and your description wants to look good in the snap
store.
 
grade: devel # must be 'stable' to release into candidate/stable channels
confinement: devmode # use 'strict' once you have the right plugs and slots
 
parts:
my-part:
# See 'snapcraft plugins'
plugin: nil

I will describe in brief some points of the file:

1. Name - The name of the package that will be assigned to it after creation
2. ersion - After the package name comes the version you need will be if you plan to update your application
3. Description - The description of your application that will be displayed in the console
4. Confinement - The mechanism of restriction for the work of the package
5. Architectures - everything is clear. package architecture. will also be indicated in the package name
6. Apps - It can be an application graphical, or console command and daemon start (service).
7. Parts - This is part of the config that will handle snapcraft

Now we type the command snapcraft in the console, then on the basis of this configuration file we get our first package named my-snap-name_0.1_amd64.snap

Several console commands that will be useful for learning and familiarization:

snap find - list of available snap packages
 
sudo snap install <package_name> - installing the package. Rights of the Root
 
sudo snap refresh <package_name> - update package
 
snap list - list of all installed snap packages in the system
 
sudo snap remove <package_name> - package deletion
 
snap changes - A very useful utility that shows information about all the changes. (installation, update, deletion)

In the next article, we'll take a look at the example of my small graphical application written in Qt, setting up and starting from anywhere in the system.

P.S. If you have any questions, edits to the article, or something else, write. I will try to answer everyone.