Setup tool for bitbake based projects

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This tool provides an easy mechanism to setup bitbake based projects.

The OpenEmbedded tooling support starts at step 2 with bitbake. The downloading of sources and then configuration has to be done by hand. Usually, this is explained in a README. Instead kas is using a project configuration file and does the download and configuration phase.

Currently supported Yocto versions:

• 2.1 (Krogoth)
• 2.2 (Morty)

Older or newer versions may work as well but haven't been tested intensively.

Key features provided by the build tool:

• clone and checkout bitbake layers
• create default bitbake settings (machine, arch, ...)
• launch minimal build environment, reducing risk of host contamination
• initiate bitbake build process

Dependencies & installation

This projects depends on

• Python 3
• distro Python 3 package
• PyYAML Python 3 package (optional, for yaml file support)

If you need Python 2 support consider sending patches. The most obvious place to start is to use the trollius package intead of asyncio.

To install kas into your python site-package repository, run

$ sudo pip3 install .

Usage

There are three options for using kas:

• Install it locally via pip to get the kas command.
• Use the docker image. In this case run the commands in the examples below within docker run -it <kas-image> sh or bind-mount the project into the container.
• Use the run-kas wrapper from this directory. In this case replace kas in the examples below with path/to/run-kas.

Start build:

$ kas build /path/to/kas-project.yml

Alternatively, experienced bitbake users can invoke usual bitbake steps manually, e.g.

$ kas shell /path/to/kas-project.yml -c 'bitbake dosfsutils-native'

kas will place downloads and build artifacts under the current directory when being invoked. You can specify a different location via the environment variable KAS_WORK_DIR.

Use Cases

1. Initial build/setup

   $ mkdir $PROJECT_DIR
   $ cd $PROJECT_DIR
   $ git clone $PROJECT_URL meta-project
   $ kas build meta-project/kas-project.yml
   

2. Update/rebuild

   $ cd $PROJECT_DIR/meta-project
   $ git pull
   $ kas build kas-project.yml
   

Project Configuration

Two types of input formats supported. For an product image a the static configuration can be used. In case several different configuration should be supported the dynamic configuration file can be used.

Static project configuration

Currently there is supports for JSON and Yaml.

header:
  version: "0.9"
machine: qemu
distro: poky
repos:
  # This entry includes the repository where the config file is located
  # to the bblayers.conf:
  meta-custom:
  # Here we include a list of layers from the poky repository to the
  # bblayers.conf:
  poky:
    url: "https://git.yoctoproject.org/git/poky"
    refspec: 89e6c98d92887913cadf06b2adb97f26cde4849b
    layers:
      meta:
      meta-poky:
      meta-yocto-bsp:

A minimal input file consist out of 'machine', 'distro', and 'repos'.

Additionally, you can add 'bblayers_conf_header' and 'local_conf_header' which are strings that are added to the head of the respective files (bblayers.conf or local.conf):

bblayers_conf_header:
  meta-custom: |
    POKY_BBLAYERS_CONF_VERSION = "2"
    BBPATH = "${TOPDIR}"
    BBFILES ?= ""    
local_conf_header:
  meta-custom: |
    PATCHRESOLVE = "noop"
    CONF_VERSION = "1"
    IMAGE_FSTYPES = "tar"    

meta-custom in these examples should be a unique name (in project scope) for this configuration entries. We assume that your configuration file is part of a meta-custom repository/layer. This way its possible to overwrite or append entries in files that include this configuration by naming an entry the same (overwriting) or using a unused name (appending).

Including in-tree configuration files

Its currently possible to include kas configuration files from the same repository/layer like this:

header:
  version: "0.9"
  includes:
    - base.yml
    - bsp.yml
    - product.yml

The specified files are addressed relative to your current configuration file.

Including configuration files from other repos

Its also possible to include configuration files from other repos like this:

header:
  version: "0.9"
  includes:
    - repo: poky
      file: kas-poky.yml
    - repo: meta-bsp-collection
      file: hw1/kas-hw-bsp1.yml
    - repo: meta-custom
      file: products/product.yml
repos:
  meta-custom:
  meta-bsp-collection:
    url: "https://www.example.com/git/meta-bsp-collection"
    refspec: 3f786850e387550fdab836ed7e6dc881de23001b
    layers:
      # Additional to the layers that are added from this repository
      # in the hw1/kas-hw-bsp1.yml, we add here an additional bsp
      # meta layer:
      meta-custom-bsp:
  poky:
    url: "https://git.yoctoproject.org/git/poky"
    refspec: 89e6c98d92887913cadf06b2adb97f26cde4849b
    layers:
      # If `kas-poky.yml` adds the `meta-yocto-bsp` layer and we
      # do not want it in our bblayers for this project, we can
      # overwrite it by setting:
      meta-yocto-bsp: exclude

The files are addressed relative to the git repository path.

The include mechanism collects and merges the content from top to buttom and depth first. That means that settings in one include file are overwritten by settings in a latter include file and entries from the last include file can be overwritten by the current file. While merging all the dictionaries are merged recursive while preserving the order in which the entries are added to the dictionary. This means that local_conf_header entries are added to the local.conf file in the same order in which they are defined in the different include files. Note that the order of the configuration file entries is not preserved within one include file, because the parser creates normal unordered dictionaries.

Dynamic project configuration

The dynamic project configuration is plain Python with following mandatory functions which need to be provided:

def get_machine(config):
    return 'qemu'


def get_distro(config):
    return 'poky'


def get_repos(target):
    repos = []

    repos.append(Repo(
        url='URL',
        refspec='REFSPEC'))

    repos.append(Repo(
        url='https://git.yoctoproject.org/git/poky',
        refspec='krogoth',
        layers=['meta', 'meta-poky', 'meta-yocto-bsp'])))

    return repos

Additionally, get_bblayers_conf_header(), get_local_conf_header() can be added.

def get_bblayers_conf_header():
    return """POKY_BBLAYERS_CONF_VERSION = "2"
BBPATH = "${TOPDIR}"
BBFILES ?= ""
"""


def get_local_conf_header():
    return """PATCHRESOLVE = "noop"
CONF_VERSION = "1"
IMAGE_FSTYPES = "tar"
"""

Furthermore, you can add pre and post hooks (*_prepend, *_append) for the exection steps in kas core, e.g.

def build_prepend(config):
    # disable distro check
    with open(config.build_dir + '/conf/sanity.conf', 'w') as f:
        f.write('\n')


def build_append(config):
    if 'CI' in os.environ:
        build_native_package(config)
        run_wic(config)

TODO: Document the complete configuration API.

Environment variables

KAS_REPO_RED_DIR should point to a directory that contains repositories that should be used as references. In order for kas to find those repositories, they have to be named correctly. Those names are derived from the repo url in the kas config. (E.g. url: "https://github.com/siemens/meta-iot2000.git" resolves to the name "github.com.siemens.meta-iot2000.git")

Development

This project uses pip to manage the package. If you want to work on the project yourself you can create the necessary links via:

$ sudo pip3 install -e .

That will install a backlink /usr/bin/kas to this project. Now you are able to call it from anywhere.

Docker image build

Just run

$ docker build -t <image_name> .

When you need a proxy to access the internet, add --build-arg http_proxy=<http_proxy> --build-arg https_proxy=<https_proxy> to the call.

Community Resources

Project home:

• https://github.com/siemens/kas

Source code:

• https://github.com/siemens/kas.git
• git@github.com:siemens/kas.git

Mailing list:

• kas-devel@googlegroups.com

• Subscription:

  • kas-devel+subscribe@googlegroups.com
  • https://groups.google.com/forum/#!forum/kas-devel/join

• Archives

  • https://groups.google.com/forum/#!forum/kas-devel
  • https://www.mail-archive.com/kas-devel@googlegroups.com/