python поведение завершения подпроцесса - PullRequest
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python поведение завершения подпроцесса

0 голосов
/ 11 июля 2020

У меня это test.py: 

#!/usr/bin/env python3
import os
import sys
from select import select
from subprocess import Popen, PIPE

with Popen(('bash', '-c', 'echo 1; sleep 1; echo 2'), stdout=PIPE) as p:
    readable = { p.stdout.fileno(): sys.stdout.buffer }
    while readable:
        fds = select(readable, [], [], 0.1)
        print(f"readable is True. fds = {fds}")
        if not fds[0]: continue
        for fd in fds[0]:
            print("In for loop")
            data = os.read(fd, 1024) # read available
            if not data: # EOF
                print(f"delelting {fd}")
                del readable[fd]
            else: 
                readable[fd].write(data)
                readable[fd].flush()
                p.kill()

Когда я его запустил, я получил следующее: 

~/tmp$ ./test.py
readable is True. fds = ([4], [], [])
In for loop
1
readable is True. fds = ([4], [], [])
In for loop
delelting 4
~/tmp$

Это то, что я ожидал. Но иногда я получал это, запустив тот же сценарий: 

~/tmp$ ./test.py
readable is True. fds = ([4], [], [])
In for loop
1
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([], [], [])
readable is True. fds = ([4], [], [])
In for loop
delelting 4
~/tmp$

Я использую Python 3.8.2/ubuntu

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