qemu-composer

qemu-composer is a python command line interface that composes a docker-compose.yml file under a prefixed/posfixed path with multiple references to many Dockerfile. These files are indexed under appropiated paths and variables, assigning a single cross-compilation images for many processor architetures within a containerized, at the current version, in a debian environment.

Whats is intented

Supose that you want a software developed in your laptop running in a Raspberry Pi with arm* architeture (like is my case).

Let's call A that software developed in your i386or x86_64. This wiil be A-i386or A-x86_64. The A software ( A-i386/A-x86_64) will be cross-compiled to another architetures, saying A-armel, A-arm64 (A-aarch64).

Using

This script is intented to be used with travis-ci, but you can use locally.

Instalation from pip

$ pip install qemu-composer

Instalation from source

$ git clone https://www.github.com/lunhg/qemu-composer.git
$ cd qemu-composer/
$ pip install -e .

Configuration

Create a .qemu.yml file that follow a hybrid structure of docker-compose.yml files and .travis.yml files.

This file will:

• create a docker-compose.yml with apropriated version field
• register a special docker image that runs QEMU
• base the qemu specific architeture, that generates a FROM <base> directive in Dockerfiles
• register a before_install command field running under root privilegies
• register install and subsequent command fields running a user with a randomic name

# Same as docker-compose `version`field
# will be copied to `<prefix>/docker-compose.yml`
version: '2'

# The registering qemu binaries to be used
register: multiarch/qemu-user-static:register

# The prefix name of images to be used in the one-time cross-compilation in Dockerfile as FROM * 
base: multiarch/debian-debootstrap

# The generated images if you want to share
image: redelivre/qemu-alpine-builder

# Where alll will builded <--prefix from cli>/.bin
prefix: .bin

# Register runtime options 
options:
  - --rm
  - --privileged

# Register runtime commands
commands:
  - --reset

# base image arches
arches:
  - armel
  - armhf
  - arm64

# base image targets
targets:
  - wheezy
  - jessie

# The environment os builds
env:
  - VAR=<name>
  ...

# RUN commands
# User is root on this point
# Useful in update apt-packages
before_install:
  - echo "`whoami` running `uname -a` at `hostname`"
  - apt-get update
  - apt-get install -y <pkg>
  ...

# User isnt root on this point
install:
  - echo "`whoami` running `uname -a` at `hostname`"
  ...
  
after_install:
  - echo "`whoami` running `uname -a` at `hostname`"
  ...

before_script:
  - echo "`whoami` running `uname -a` at `hostname`"
  ...
  
script:
  - echo "`whoami` running `uname -a` at `hostname`"
  ...
  
after_script:
  - echo "`whoami` running `uname -a` at `hostname`"
  ...

Running tests

• Simple test:

$ pytest

• Complete test:

$ sudo COVERALLS_TOKEN=<token> tox

If you found a compilation error from cffi, module, you will need to add a CFLAGS environment variable.

This occurs when you are using a non-debian OS, like a Archlinux:

$ sudo COVERALLS_TOKEN=<token> CFLAGS=-I/<path-to-libffi> tox

LIBFFI paths:

• Archlinux:
  • path: /usr/lib/libffi-/include:
  • installing: pacman -Syu libffi

Running as CLI

$ qemu-composer

This command is alias for:

$ qemu-composer --prefix $PWD/<define prefix in file> --file .qemu.yml

Options

Option name	long form	short form	description
prefix	--prefix	-p	Set a prefix where qemu-composer runs (default: $PWD)
file	--file	-f	The file where qemu-composer is configured (default: .qemu.yml)
group	--group	-G	The group of a passwordless user in qemu
gid	--gid	-g	The gid of the group
uid	--uid	-u	The uid of passwordless user of qemu