xAAL Python stack

Requirements

To install xAAL for Python, you need Python3. Python version 3 isn't mandatory but highly recommended (some parts haven't be tested with Python 2 since a while). Install the following packages:

• subversion
• python3-dev
• libsodium-dev

For Debian / Ubuntu users:

$ apt-get install subversion python3-dev libsodium-dev
# recommended
$ apt-get install python3-virtualenv

Install

Right now, there is no public release (pip based) of xAAL Python binding, so you have to install things from SVN or archive.

You can use virtualenv (recommended).

First build a virtualenv :

# for debian / ubuntu
$ python3 -m virtualenv --python=python3 xaal_env

# or
$ virtualenv3 xaal_env

Everytime, you want to use the binding, you must source the activate script.

$ source xaal_env/bin/activate

Download sources from SVN:

$ svn checkout https://redmine.telecom-bretagne.eu/svn/xaal/code/Python/trunk/ xaal_svn

First, install the xaal.lib package:

$ cd xaal_svn/libs/lib/
$ python setup.py develop

Install the monitor lib (needed by Dashboard, REST API..)

$ cd xaal_svn/libs/monitor/
$ python setup.py develop

Install the schemas (needed by some devices)

$ cd xaal_svn/libs/schemas/
$ python setup.py develop

Install the tools

$ cd xaal_svn/apps/tools
$ python setup.py develop

You can use the python setup.py install instead of develop, but modification in source files, won't be applied, you have to re-install it. Right now develop, is the best option.

Create the configuration file in your home directory:

$ mkdir ~/.xaal/
$ cp xaal_svn/libs/lib/xaal.ini.sample ~/.xaal/xaal.ini
$ xaal-keygen

xaal-keygen will compute an key for a given passphrase. Edit the xaal.ini file according to your needs.

Tests

First, you can launch a message dumper with this tools

$ xaal-dumper
$ or xaal-tail 0

To start an fake lamp:

$ cd xaal_svn/devices/test/DummyDevices/
$ python lamp.py

To check devices, you can use:

# search alive devices
$ xaal-isalive

# search lamp.basic devices
$ xaal-isalive lamp.basic

# search any kind of lamp
$ xaal-isalive lamp.any

# display description / attribute
$ xaal-info xxxxxxxxxxxxxx <- uuid

# display description / attribute for all devices
$ xaal-walker

# same but on for lamp devices
$ xaal-walker lamp.any

Coding style

Every xAAL program (device, gateway, apps) use a namespace. For example, xaal.rest, or xaal.zwave. By convention, you can run everything just by calling the namespace module.

# to run the meta data sever:
$ python -m xaal.metadb

# to run the dashboard (web interface)
$ python -m xaal.dashboard

# to run the Zwave gateway
$ python -m xaal.zwave

Of course, you find need to install needed packages.

Notes

• If you use xAAL on multiple hosts, take care of the system clock. xAAL use date/time to cypher the messages. If clocks differs, you will receive an error message about a "replay attack". In production, NTP is your best friend. A window of 1 minutes is accepted, but no more.

FAQ

• Python terminated by signal SIGSEGV: You probably forgot to setup the key in config file.

• Configuration files are hard to read / edit. Why don't you use YAML or XML for config ?

  First, we need something that support nested config so we can not use ConfigParser. Next, we tested severals YAML packages, but they are really slow to import. We want xAAL stack to load as fast as possible, and importing big packages (like PyYAML) take around 0.5 sec on a Raspy. This is way too much for a simple command-line tools like xaal-info for example. We want to provide a better user experience.