Séléné

Séléné is a lightweight and versatile framework to build Lua event driven application.

Séléné provides :

• tasks list management : tasks needing to run in sequence or which doesn't need to be real-time are queued. They will be launched when main application thread is idle
• Asynchroneous tasks : tasks can detach from their mother process. Unlike Lua's coroutine, they are working totally independently, without having to manage concurrent access to their own context. Especially suitable for realtime actions.
• data exchange between tasks are managed using shared variables or data queues (have a look on SelShared and Collection objects). Notez-bien : due to Lua's limitation, detached tasks can't access to objects (including functions) declared in the main thread, Shared objects and collection handle data sharing as well as locking to avoid race condition and concurrent access.
• Tasks are waked-up by various types of events :
  • timers (absolute and relative times)
  • MQTT messages arrivals. Consequently, an external application can trigger a tasks by sending an MQTT message. Séléné provides some APIs to expose MQTT payload to Lua scripts
  • files’ events
  • Unix events
  • …

Thanks to plug-ins, Séléné allows to easily create events driven dashboard :

• Text based ones using the industry standard Curses library
• Graphicals ones :
  • Tiny OLED displays
  • Linux Framebuffers so without having to install and manage obese X layer

Dependencies

• PAHOc can be found on its website. Mandatory to handle MQTT layer.

And if you want to use related plugin (mostly to create smart dashboards) :

• Curses : the well known text based semi graphics interface
• OLED : support of SSD1306, SH1106, SSD1327 or SSD1308 small OLED displays. You have to use my own fork of ArduiPi_OLED or derivated as containing lot of additional features compared to its baseline.
• libdrm, libkms and Cairo and dependancies : needed by DRMCAIRO plugin, a graphical framework to build dashboard without having to install X itself. Notez-bien : DRMCairo has now a fallback in case DRM/KMS is not working, using directly the FrameBuffer.

My systems are mostly under Linux/Gentoo, but one of my SBC is running Armbian, I wrote a special installation note for Debian derived.

Deprecation

• DirectFB : X free lightweight graphical framework. After a long and sad story, it seems it definitively lost its official support and being deprecated on most of distribution. It's seem the most updated version is on this fork. DirectFB got less and less support in Linux distribution, source compilation is problematic, I'll not work anymore on this plugin. By the way, it's working pretty well as it is. Replacement is DRMCairo.

Installation

1. install dependencies
2. extract Séléné sources "somewhere" (a.k.a in a temporary directory)
3. optionally, if you want to change compilation option
   1. install LFMakeMaker
   2. customise remake.sh as per your needs : activate module by settings USE_DIRECTFB (deprecated), USE_DRMCAIRO, USE_CURSES and USE_OLED. Optionally, change plugging directory with PLUGIN_DIR (not recommended).
   3. execute remake.sh to update Makefiles.
4. make
5. execute install.sh
6. as root, run ldconfig

---

Unfortunately, I don't have times for a decent documentation. But you may find some informations in :

• all comprehensive examples files in Selenites???? subdirectories.
• probably in source code as well.

All good wishes are welcome if someone wants to get on with the job.