I have a script that read data from Serial Port, so I have an infinite loop that always fill my data to global variable, and also I schedule a function that run every X seconds to post in the database, and this function also use the same global variable.
Here's a small example I create it to show you my situation :
import serial import schedule import threading shared_var = [] def save_to_db(): print(threading.current_thread()) global shared_var for l in shared_var: print(l) shared_var.clear() def run_threaded(job_func): job_thread = threading.Thread(target=job_func) job_thread.start() ser = serial.Serial() # initialize the serial ser.baudrate = 115200 # set the baud rate : default 115200 ser.port = "/dev/ttyUSB0" # set the port to use ser.timeout = 30 ser.write_timeout = None if not ser.is_open: ser.open() # Open port ser.write(b'scan=01\r\n') # Stop scan if already started schedule.every(5).seconds.do(run_threaded, save_to_db) while 1: schedule.run_pending() line = ser.readline() shared_var.append(line) print(threading.current_thread()) Is this code can cause a problem ? more specific what will happen if the MainThread (the one that read from Serail Port and write to shared_var) write to the shared variable between the 2 thread and in the same moment the other Thread read from the variable, is This will cause a problem because the 2 threads gonna access the same global variable in the same time ? and if yes It's a problem should I use mutex mechanism for that ?
