subprocess 实时打印输出，并检测命令行的返回值

tasks.py

# coding: utf-8
from .celery import app
# 关注下这个库，比较方便写 linux 命令行工具
# https://docs.python.org/3/library/shlex.html

@app.task(bind=True, max_retries=2, acks_late=True)
def convert_video(self):
    print('====== start =======')
    import subprocess
    import os
    try:
        cmd = ['ffmpeg','-i', 'zy 1.rmvb', '-c:v', 'libx265', 'zy 1.mp4', '-y']
        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, universal_newlines=True, errors='ignore')
        while p.poll() is None:
            output = p.stdout.readline()            
            if output:
                print(output.strip())
        if p.poll() == 255:
            msg = 'ctrl + c detected'
            print(msg)
            raise Exception(msg)
        elif p.poll() == 1:
            print('wrong file format')
        elif p.poll() == 0:
              print('====== end =======')
        else:
            print('error detected, ffmpeg returned with code: ', p.poll())
    except Exception as e:
        print('exception here, retry task next time.', e)
        raise self.retry(exec=e)