Python Asynchronously Calling Synchronous Function

Question

I am new to async programming in Python and the internet has not helped me to solve my problem - does anyone of you have a solution?

I have an infinite loop, in which some sensor data is read. However, the sensor reading is quite slow, so I want so await the sensor signals.

My expectation of it looks like this (just the schematics):

    import bno055 #sensor library
    import asyncio
    
    aync def read_sensor():
           altitude=bno055.read()
           #..and some other unimportant lines which I hide here
           return altitude


    def main():

       while 1:
          await current_altitude= read_sensor() #??? how can I "await" the sensor signals?
          #....some other lines which I hide here, but they need to run syncronously
          print(current_altitude)

       
      

   main()

Thank you in advance

If `bno055.read` is not asynchronous you need to wrap it somehow in a thread or similar. — mkrieger1, Jun 23 '20 at 15:49
Does this answer your question? [How to use asyncio with existing blocking library?](https://stackoverflow.com/questions/41063331/how-to-use-asyncio-with-existing-blocking-library) — mkrieger1, Jun 23 '20 at 15:50

alex_noname · Answer 1 · 2020-06-23T16:31:03.733

0

To await function doing blocking IO you can run it by means of run_in_executor

def read_sensor():
    altitude=bno055.read()
    #..and some other unimportant lines which I hide here
    return altitude

loop = asyncio.get_running_loop()
altitude = await loop.run_in_executor(None, read_sensor)

edited Jun 23 '20 at 16:31

answered Jun 23 '20 at 16:14

alex_noname

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Yes, i updated answer, `read_sensor` should not be `async` now – alex_noname Jun 23 '20 at 16:34
It returns a syntax error for "await loop.run_in_executor(None, read_sensor)" – haakla321 Jun 24 '20 at 12:24

Python Asynchronously Calling Synchronous Function

1 Answers1