We are doing a very similar thing right now.
The system we have to replace is a RPi-CM based mini-server which
- serves a visualisation for a smarthome (HTTPS server, OAuth2)
- connects to various field busses (RF and cable)
- provides a Hub for those (similar to, but not as feature rich as: https://www.home-assistant.io/)
- handles some hard-keys and LEDs
- is OTA-updateable
The current system uses:
- python (Hub, some scripts)
- node (server)
- C and Cpp (bus stacks)
- .deb (updates)
- bash (some scripts)
- systemd
- crazy test system
- …more
We decided to go for Elixir/Nerves for the next generation.
@mindok has very nicely summarized the reasons for that decision, but I want to point out:
- functional language (Elixir or Erlang is the only functional language I’d consider for an embedded system. Functional languages have great advantages I won’t go into here, but the biggest plus I expect is better testability)
- we can do everything (but some fast-hard-realtime stuff) in one language. This is a big plus, especially for a small team.
- possibility to run on small platforms like iMX6UL - even without Linux, see GRiSP2
- erlang’s binary pattern matching is a game changer when implementing protocols (I did put Elixir to the test by implementing the part of the system I saw it least fit for: the KNX protocol stack. This turned out very nicely)
- Nerves is a great tool for building embedded software systems and makes OTA updates simple. (Our current desktop-OS and .deb system is a pain in the ass with thousands of servers in the field)
- OTP (Supervision tree kills systemd, we can create on (umbrella/poncho?) project for the whole system.)
- Elixir is a great language, with a very good ecosystem including a great community. There are lots of people here, that are here because they’ve already seen some other stuff.
