ledd - led driving daemon

Overview

Ledd is a daemon responsible of controlling the leds of a product. It is controlled by a [libpomp] socket on any transport method it supports. Several led controlling methods, or userland drivers are provided, such as gpios and pwms. "Virtual" leds can be controled too, writing data on a file or on a libpomp socket.

The main parts of ledd have their own README.md file in their directory. A full HTML documentation is generated from them in doc/generated/ledd.html, by executing ./doc/generate.sh at the root of ledd's source directory.

Quick start

The following instructions will help you build and configure a ledd daemon, to run on a pc, simulating a tri-color led with a gtk window.

install the needed tools, as root

 apt-get update
 apt-get install parallel git python3 make gcc pkg-config g++ \
     libcunit1-dev liblua5.2-dev linux-headers-amd64 python-gtk2 \
     python-gobject lua5.2

prepare a workspace with the source and all the needed dependencies

 mkdir ledd
 cd ledd
 wget -O - https://raw.githubusercontent.com/Parrot-Developers/ledd-ng/master/doc/sources | parallel git clone

setup convenient environment variables for the build
```
 . ledd-ng/doc/setenv
```
build:
```
 alchemake all final -j 5
```

create a configuration

 sed "s#\(workspace = \).*#\1\"$PWD/\"#g" ledd-ng/config/global.conf > global.conf

setup convenient environment variables for runtime

 . Alchemy-out/linux-native-x64/final/native-wrapper.sh

launch ledd
```
 ledd-ng ./global.conf &
```
If problems arise, increase the verbosity by setting the environment variable ULOG_LEVEL=D and adapt the configuration.

in another window, launch the socket driver python example client in background

 PYTHONPATH=./libpomp/python ./ledd-ng/utils/sldUI.py unix:/tmp/socket_led_driver.sock &

then ask ledd to play a pattern
```
 ldc set_pattern color_rotation false  
```
and see the result in the client's window.
then you can quit ledd with
```
ldc quit
```

Features

Lua configuration files

No need to know the lua syntax, example configuration files are provided in config/ and should be straight forward to understand.

Three configuration files (which can be merged in one big file) are used :

global.conf : handles ledd's global configuration.
platform.conf : describes the leds present on the product, with their channels and the userland driver they use
patterns.conf : contains the ledd patterns descriptions, independently of the hardware it is used on

Full access to lua's standard library and features is available, although not mandatory to use.

Plugin system

The plug-in system allows for now to register three types of things :

a userland led driver, basically by implementing a set_value callback
a new led state transition, more info in the ledd_plugins/transitions folder's readme
lua global values or functions, accessible in platform.conf or patterns.conf

Examples of drivers, transitions and lua globals plug-ins are provided in the ledd_plugins/ directory.

Different integration methods available

Depending on the situation you're in, you have the following solution in order to integrate ledd :

as a standalone system daemon, a boxinit service file is provided in config/, but any service monitoring facily can be used, such as systemd or busybox' init.
this is the nominal case
as a shared library, to be integrated on an event loop via it's exposed fd
if you want, for example, to limit the processes in resources constrained environments (e.g. P6 products)
as a static library, in an event loop and with all the plugins built-in
the typical use case is for an installer UI driving the leds

Other features

simulator friendly
With the socket plugin, a libpomp client can receive the values sent by ledd. An example client is provided in utils/sldUI.py.
logs via ulog