[PYTHON/COMMON] Popen 클래스 : stdin 변수와 communicate 메소드를 사용해 자식 프로세스 처리 결과 구하기

■ Popen 클래스의 stdin 변수와 communicate 메소드를 사용해 자식 프로세스의 실행 결과를 구하는 방법을 보여준다.

▶ 예제 코드 (PY)


import os
import subprocess

def runOpenSSL(sourceBytes):
    environmentDictionary = os.environ.copy()

    environmentDictionary["OPENSSL_PASSWORD"] = b"\xe24U\n\xd0Ql3S\x11"

    popen = subprocess.Popen(
        ["openssl", "enc", "-pbkdf2", "-pass", "env:OPENSSL_PASSWORD"],
        env    = environmentDictionary,
        stdin  = subprocess.PIPE,
        stdout = subprocess.PIPE
    )

    popen.stdin.write(sourceBytes)

    popen.stdin.flush() # 자식 프로세스가 입력을 반드시 받도록 만든다.

    return popen

popenList = []

for _ in range(3):
    randomBytes = os.urandom(10)
    popen = runOpenSSL(randomBytes)
    popenList.append(popen)

for popen in popenList:
    outputBytes, errorBytes = popen.communicate()
    print(outputBytes[-10:])

"""
b'\xf1\x88n=\xedi[\xeb\xa3p'
b'RI\x95\x1b\xe5_\xdc$\xa3<'
b'\xcd4RQ\x89@`\x98\xa8\x95'
"""

import os

import subprocess

def runOpenSSL(sourceBytes):

environmentDictionary = os.environ.copy()

environmentDictionary["OPENSSL_PASSWORD"] = b"\xe24U\n\xd0Ql3S\x11"

popen = subprocess.Popen(

["openssl", "enc", "-pbkdf2", "-pass", "env:OPENSSL_PASSWORD"],

env = environmentDictionary,

stdin = subprocess.PIPE,

stdout = subprocess.PIPE

)

popen.stdin.write(sourceBytes)

popen.stdin.flush() # 자식 프로세스가 입력을 반드시 받도록 만든다.

return popen

popenList = []

for _ in range(3):

randomBytes = os.urandom(10)

popen = runOpenSSL(randomBytes)

popenList.append(popen)

for popen in popenList:

outputBytes, errorBytes = popen.communicate()

print(outputBytes[-10:])

"""

b'\xf1\x88n=\xedi[\xeb\xa3p'

b'RI\x95\x1b\xe5_\xdc$\xa3<'

b'\xcd4RQ\x89@`\x98\xa8\x95'

"""