Python subprocess: callback when cmd exits

Question

I\'m currently launching a programme using subprocess.Popen(cmd, shell=TRUE)

I\'m fairly new to Python, but it \'feels\' like there ought to be some api

Answer 1

I had same problem, and solved it using multiprocessing.Pool. There are two hacky tricks involved:

1. make size of pool 1
2. pass iterable arguments within an iterable of length 1

result is one function executed with callback on completion

def sub(arg):
    print arg             #prints [1,2,3,4,5]
    return "hello"

def cb(arg):
    print arg             # prints "hello"

pool = multiprocessing.Pool(1)
rval = pool.map_async(sub,([[1,2,3,4,5]]),callback =cb)
(do stuff) 
pool.close()

In my case, I wanted invocation to be non-blocking as well. Works beautifully