justin

Run just commands inside a container.

Installation

System-wide:

$ just install

User:

$ just install ~/.local

Running just

$ justin --workspace . just ...
$ justin --workspace . --copy just ...

$ justin \
  -E podman \
  -F ci
  -w . \
  -v ./artifacts:/artifacts\
  just -f ci.justfile somestage

Building images

Default image:

$ justin build 

Flavors

$ justin --flavor minimal build
$ justin --flavor ci build
$ justin -F /path/to/my/flavor build

justin supports a concept of "flavors", which is a way to customize how images are built. justin ships with the following flavors:

• minimal (default one) - creates a minimal image viable for running just commands.
• ci - creates a bigger image with some tools preinstalled, more suitable for continuous integration systems.

You may also point justin to a the directory with a custom flavor, which is located outside of the original build context. justin will copy and use your flavor.

During build flavors are copied to /install directory within a built container.

Flavors have the following requirements:

• they must provide a Flavor Configuration File (see below)
• inside a flavor directory there must be an install directory, which will be copied into /install within the container, but which will be removed from the final image
• they must provide an executable /install/install.sh
• they must install /usr/bin/tini and just executables within the container
• they must provide /usr/local/bin/docker-entrypoint executable within the container, which will be used as container entrypoint

Flavor Configuration File

Each flavor must provide a flavor.toml file with [build.args] section. Each field from the [build.args] section will be used as a --build-arg during the build. In case of name conflicts between build args in flavor.toml and --build-arg passed in command line, command line ones have priority.

Example:

[build.args]
FROM_IMAGE = "debian"
FROM_TAG = "trixie-slim"

VENDOR = "John Doe's Company"
AUTHORS = "John Doe"
VERSION = "1.0"
ARCH = "x86-64"
DESCRIPTION = "One image to rule them all"
JUST_EXECUTABLE = "just"