Something like Threading/Queue in MicroPython?

[lukesky333]

Hi guys,

I've a script at my desktop and I'll try to port it to MicroPython (esp. ESP32). Therefore I need libraries like "threading" and "Queue".
Is there something similar in MicroPython?

[fstengel]

Not as such. However there are alternatives on the ESP32:

• uasyncio, but that might cause you to completely rewrite your scripts
• use lightweight threads with the _thread module. It is documented for the lobo port. However, I cannot find documentation for the mainline (apart form the fact that it is experimental and derived from the CPython module...).

[mattyt]

Without knowing your use case, it's hard to say what the right solution is - but asyncio is a fair bet. Peter Hinch has implemented Queue for asyncio. Check it out and see if it fits.

Threads are possible but they come with added complexity and a less mature implementation (no threading library only the _thread primitives) and documentation. If you do want to pursue this approach then Damien's talk on _thread for the ESP32 on MicroPython may be useful.

[lukesky333]

I want to read data from two serial connections simulatneously. The challenge is to get the data immediately, without delay - to get the correct "timestamp". Therefore I use threading and under Ubuntu it is working fine.

Later I put the data in the queue to handle it...

Now I want to port this to ESP32 and I'm looking for a solution/alternative for Queue and threading...

[pythoncoder]

I suggest you quantify "simultaneously". Any scheduler, pre-emptive or cooperative, introduces latency. The amount depends on the target. For absolute minimum latency you'd need to handle the UART IRQ's directly in code. Even that isn't a panacea: ESPx chips aren't known for fast response to IRQ's.

If you can tolerate latency in the low tens of ms I would suggest using the uasyncio stream mechanism rather than queues. My uasyncio fork suits exactly this type of application by minimising latency.

Whether _thread offers any latency benefit on ESP32 is moot and depends on the characteristics of the underlying vendor code. You'd need to measure the two approaches to determine which was best.

[pythoncoder]

...Peter Hinch has implemented Queue for asyncio...

To prevent misunderstanding uasyncio.queues is a part of uasyncio and was written by Paul Sokolovsky. I merely documented its use.

[lukesky333]

...
Even that isn't a panacea: ESPx chips aren't known for fast response to IRQ's.
...

Is there another hardware with faster response? I need MicroPython and 2 hardware serial connections...

[rcolistete]

Pyboard 1.1/D.

[lrb@lrb.no]

I want to read data from two serial connections simulatneously.

Did you solve this? I'm looking into a similar task: reading and writing four serial ports, having a main handler that responds to received data and decides where to send the data.
/Lars