Snapcraft rocks

This repository contains Snapcraft rocks and the sources to generate them. The rocks are OCI-compliant container images that run different versions of Snapcraft to create snaps.

Each rock in this repository bundles a specific version of Snapcraft, targeting snaps for a specific core. The currently supported versions and cores have the following tags:

• 7_core22, bundling the latest Snapcraft 7 capable of building core22 snaps.
• 8_core22, bundling the latest Snapcraft 8 capable of building core22 snaps.
• 8_core24, bundling the latest Snapcraft 8 capable of building core24 snaps.

Usage

The contained Snapcraft needs access to the directory containing the project that you want to snap (the directory containing the snap folder with a snapcraft.yaml file), and this directory needs to be exposed to the running container as /project. For example, the following command will mount the current directory into a new container and run pack on the latest version of Snapcraft 7 for core22 snaps::

docker run -it -v pwd:/project ghcr.io/canonical/snapcraft:7_core22 pack

Other commands, like clean or build, can be called simply by replacing pack in the example above. Every argument provided after the image name is forwarded to Snapcraft.

Reporting bugs

Please report all issues, improvements and feature requests at https://github.com/canonical/snapcraft-rocks.

Development

The sources in this repository are capable of building different versions of Snapcraft, targeting snaps for different cores. The sources are separated into Git branches in the form coreX-Y, where X is a core number (like 22 or 24), and Y is a major version of Snapcraft (like 7 or 8).

For example, branch core22-7 contains the Rockcraft project to create a rock containing the latest stable version of Snapcraft 7 and can be used to create snaps targetting core22.

Supported versions

These are the currently supported combinations of Snapcraft versions and cores:

- Branch ``core22-7``, for rocks with latest Snapcraft 7 to build ``core22``
  snaps.
- Branch ``core22-8``, for rocks with latest Snapcraft 8 to build ``core22``
  snaps.
- Branch ``core24-8``, for rocks with latest Snapcraft 8 to build ``core24``
  snaps.

Requirements

• Rockcraft_ is needed to generate the rocks (minimum version 1.1.0).
• Docker or some other engine is needed to create containers from the images. Note: Docker can sometimes make iptables changes that break LXD instances used by Rockcraft. See this page for details.

Instructions

- First, choose a target Snapcraft version and core and checkout the appropriate
  branch. As an example, let's use branch ``core22-7``.
- Run ``rockcraft pack`` to create a rock whose name starts with
  ``snapcraft-core22_7``. The remainder of the name depends on the actual full
  version of Snapcraft and the host architecture. For example, running this
  command on an ``amd64`` machine when ``7.5.4`` is the latest stable Snapcraft
  7 version will yield a rock called ``snapcraft-core22_7.5.4_amd64.rock``.
- Use a tool like `Skopeo`_ to convert and load the rock into Docker's local
  registry. You can use the ``skopeo`` binary included in Rockcraft's snap for
  this (see the `instructions`_ on Rockcraft's docs).
- Finally, use Docker to create containers to run Snapcraft as described in the
  `Usage`_ section above.

.. _rocks: https://canonical-rockcraft.readthedocs-hosted.com/en/latest/explanation/rocks/#rocks-explanation
.. _Snapcraft: https://www.snapcraft.io
.. _Rockcraft: https://github.com/canonical/rockcraft
.. _Docker: https://www.docker.com/
.. _Skopeo: https://github.com/containers/skopeo
.. _instructions: https://canonical-rockcraft.readthedocs-hosted.com/en/latest/tutorials/hello-world/#run-the-rock-in-docker
.. _this page: https://canonical-craft-providers.readthedocs-hosted.com/en/latest/explanation/#failure-to-properly-execute-commands-that-depend-on-network-access