micropython-lib
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Handle MemoryError in aioble_central.py scanner event
I am using the scanner as follows in my application code
# The 'scanner' is of type 'scan' defined in aioble
async with scan(duration_ms=10000, # The length of the scan cycle in milliseconds.
interval_us=30000, # The time between each scan listen start
window_us=15000, # The length of time during the scan interval one is actually listening
# If interval_us = window_us the scan is non stop (so called fully duty cycle)
# Background scanning usually sets the window_us to be less than interval_us.
active=True) as scanner: # active = True means do scan requests to get scan responses
# For PHD we always want to do active scans.
However, every once and a while in the scan event handler a MemoryError is thrown while trying to load a result into the queue shown below:
if event == _IRQ_SCAN_RESULT:
addr_type, addr, adv_type, rssi, adv_data = data # data here is a tuple[int, bytes, int, int, bytes]
if not _active_scanner:
return
try:
if queue_scan:
_active_scanner._queue.append((addr_type, bytes(addr), adv_type, rssi, bytes(adv_data)))
_active_scanner._event.set()
except MemoryError:
queue_scan = False
logger.error('LNI: AIOBLE: Memory allocation error queuing an advertisement/scan response.') # type: ignore
import gc
gc.collect()
I have added a handler for the exception and would like to be able to recover from the error but am not sure what else I need to do. With the code shown above, the scanner restarts after 10 seconds but ScanResult objects are no longer created. Not sure why. Do I need to set the event? Do I need to add a filter that blocks repeat advertisements in a given scan cycle? Maybe it is simply not possible to recover from such an error?
Any help is greatly appreciated, especially from the code author.