asyncio and subprocess

asyncio-forever-loop.py

#!/usr/bin/env python

import asyncio
import logging

async def periodic_worker(loop):
    wait_sec = 1.0
    while True:
        t0 = loop.time()
        await asyncio.sleep(wait_sec)
        delta_t = loop.time()-t0
        print('Delta T: %.3fs, Error: %.2fms'%(delta_t, (delta_t-wait_sec)*1000))

def main():
    logging.getLogger('asyncio').setLevel(logging.WARNING)
    loop = asyncio.get_event_loop()
    
    task = asyncio.ensure_future(periodic_worker(loop), loop=loop)
    try:
        loop.run_forever()
    finally:
        loop.close()

if __name__=='__main__':
    main()

asyncio-parallel-tasks.py

#!/usr/bin/env python

import asyncio
import logging

async def worker(loop, name, sec):
    await asyncio.sleep(sec)
    print('{} hello'.format(name))

def main():
    logging.getLogger('asyncio').setLevel(logging.WARNING)
    loop = asyncio.get_event_loop()
    
    tasks = [
        asyncio.ensure_future(worker(loop, 'A', 3)),
        asyncio.ensure_future(worker(loop, 'B', 4)),
        asyncio.ensure_future(worker(loop, 'C', 2)),]
    try:
#        loop.run_forever()
        loop.run_until_complete(asyncio.gather(*tasks))
    finally:
        loop.close()

if __name__=='__main__':
    main()

test_pool.py

#!/usr/bin/python3

from multiprocessing import Pool
from time import sleep
from time import ctime

def f(x):
  print("%s Sleep for %ssec"%(ctime(), x))
  sleep(x)
  print("%s Sleep for %ssec Done"%(ctime(), x))

if __name__ == "__main__":
  p = Pool(2)
  for i in range(10):
    p.apply_async(f, args=(i,))
  print("%s Start"%ctime())
  p.close()
  p.join()  

test_pool_w_init.py

#!/usr/bin/python3

from multiprocessing import Pool
from multiprocessing import current_process

def calc(n):
  sum = 0
  for i in range(n):
    sum = sum + i;
  print('%s, %s'%(n, sum))

def init():
  print("start %s"%current_process().name)

if __name__ == '__main__':

  p = Pool(initializer=init)
  p.map(calc, [10000,2000,300,400,500,600,700,800,900,1000,1010])
  p.close()
  p.join()