How to run mp_embed_exec_str in nonblocking state.

[nikhil-robinson]

Hello there i was testing the embedded example and the mp_embed_exec_str is blocking if i add an infinite while loop. how to exit out without destining the mpy. i am using esp32 port.

[jimmo]

@nikhil-robinson I'm not quite sure what you're asking for -- what do you mean by "how to exit out"?

Also why are you using the embedded example in conjunction with the esp32 port?

[nikhil-robinson]

Hi @jimmo lets say i wrote a program for printing hi in a while loop

while True:
    print("hI)

if i run this program using the mp_embed_exec_str function there is no way to stop the program and the mp_embed_exec_str function blocks the entire code flow . i want to exit out of the while loop after some time period ,

i am not using the entire example i am just using the mp_embed_exec_str function from the embedded example . i wanted run python code inside of my application without repl so i took the function mp_embed_exec_str from the embed example and port it to esp32 everything works but if there is a while loop i am unable to exit out of the execution

[jimmo]

What do you want to cause the loop to exit?

[nikhil-robinson]

lets say i have multiple string of program .

program 1

while True:
    print("hI")

program 2

while True:
    print("test1")

program3

while True:
    print("hello")

i want to execute these programs in sequence with a delay of 2 sec in between and my delay is controlled by an external source in my esp-idf project.

[jimmo]

You should make the programs responsible for terminating themselves -- either by providing a method they can call to know when to stop, or they can use time.ticks_ms / time.ticks_diff.

[nikhil-robinson]

for my application this does not apply, the end user will only write the python code and need to update it when ever they want . My question is how is REPL doing it even if we have infinite while loop sending ctrl+c will stop the program right is it possible to implement the same on my case like an external event will send ctrl+c to the running program ?

[karfas]

@nikhil-robinson: If you allow to execute arbitrary python code written by the user, you could

• document that user-supplied code must complete within X milliseconds.
• use a watchdog or one of the hardware timers to reboot the device (maybe remember this function as faulty and don't execute it again).

However, arbitrary code gives the user a gazillion other ways (besides long-running loops) to brick the device you are building.

[nikhil-robinson]

is ther any way to send ctrl +c to the program the same way the repl doees ?

[karfas]

Use the source, Luke.

See https://github.com/micropython/micropython/blob/master/py/scheduler.c#L50

I assume you could create a simple user extension calling mp_sched_exception() similar to the keyboard interrupt.