Spawn process to write in background

write_background.py

from multiprocessing import Pool
import numpy as np
from time import sleep
import logging as l

l.basicConfig(format = "%(asctime)-15s [Process: %(process)s] %(message)s", level=l.DEBUG)

def write_your_array(filename, a):
    l.info("writing %s in background process" % filename)
    # implement writing
    sleep(10)
    l.info("%s written" % filename)

if __name__ == "__main__":
    # just need to have 1 background process
    WritePool = Pool(1)

    l.info("The main program started")

    your_array = np.zeros(10)
    WritePool.apply_async(write_your_array, ("file1.txt", your_array.copy()))
    l.info("I am doing more computation in the main program (1)")

    # queue up another 
    your_other_array = np.zeros(10)
    WritePool.apply_async(write_your_array, ("file2.txt", your_other_array.copy()))

    l.info("I am doing more computation in the main program (2)")
  
    l.info("I am done in the main program, I wait for the writing to complete")
    WritePool.close()
    WritePool.join()

Example output on my machine:
run write_background.py
2012-06-16 11:59:18,948 [Process: 8988] The main program started
2012-06-16 11:59:18,949 [Process: 8988] I am doing more computation in the main program (1)
2012-06-16 11:59:18,951 [Process: 9052] writing file1.txt in background process
2012-06-16 11:59:18,952 [Process: 8988] I am doing more computation in the main program (2)
2012-06-16 11:59:18,952 [Process: 8988] I am done in the main program, I wait for the writing to complete
2012-06-16 11:59:28,956 [Process: 9052] file1.txt written
2012-06-16 11:59:28,957 [Process: 9052] writing file2.txt in background process
2012-06-16 11:59:38,964 [Process: 9052] file2.txt written