modbus refactor

[martgras]

Hi @stegm - thanks for your recent modbus contributions.
Do you mind having a look at my https://github.com/martgras/esphome/tree/modbus-queue branch
(changes : 4636161)
I'm currently testing it but want to make sure it doesn't break things.
The motivation is improving support for more than one modbus device.
If a device sends a request while another device is waiting for a response the data canbe corrupted (CRC errors ....).
The queue based approach should enforce strict serialization of outgoing commands

[stegm]

Do you mind having a look at my https://github.com/martgras/esphome/tree/modbus-queue branch

Sure! Give some time for it.

[stegm]

Hi @martgras,
I've take a first look at your commit (I first focused on C++ files, doing python later).
I though you introduced a queue for sending requests which will dispatch the response to callback - which I find a very good idea. But I only see the type declaration for the callback but no code. Have you committed everything?
Nonetheless I added some comments to your existing code.

[martgras]

Thanks you very much - it always helps if someone else has a look at (my) code.
Just pushed the changes

Python should be ok just added 2 properties (send_direct and dont_drop..).
As you noted probably these are not really required - undecided if should keep them for now and remove in 1 month or boldly remove them assuming there will be no regressions anywhere :)

[martgras]

Oh I nearly forgot - if you still want to look at the code I made a PR now esphome#3028 so you can do an "official" review

[martgras]

.. are you on discord?
If you go to https://discord.gg/KhAMKrd esphome topics are discussed and we can also chat directly (same alias as here for me).
While there is some noise you can learn quite a bit about esphome by having a look at questions and answers

[stegm]

Yess I have a discord account and use it sometime (stegm#2806)