我在从子进程标准输出管道获取输出时遇到了一些困难。我正在通过它启动一些第三方代码,以提取日志输出。直到最近更新第三方代码为止,一切都工作正常。更新后,python 开始无限期地阻塞,并且实际上不显示任何输出。我可以手动启动第三方应用程序并查看输出。
我正在使用的代码的基本版本:
import subprocess, time
from threading import Thread
def enqueue_output(out):
print "Hello from enqueue_output"
for line in iter(out.readline,''):
line = line.rstrip("\r\n")
print "Got %s" % line
out.close()
proc = subprocess.Popen("third_party.exe", stdout=subprocess.PIPE, bufsize=1)
thread = Thread(target=enqueue_output, args=(proc.stdout,))
thread.daemon = True
thread.start()
time.sleep(30)
如果我用 Third_party.exe 替换此脚本,则效果非常好:
import time, sys
while True:
print "Test"
sys.stdout.flush()
time.sleep(1)
所以我不清楚是否需要施展魔法才能使其与原始命令一起工作。
这些都是我尝试过的 subprocess.Popen 行的所有变体,但没有成功:
proc = subprocess.Popen("third_party.exe", stdout=subprocess.PIPE, bufsize=0)
proc = subprocess.Popen("third_party.exe", stdout=subprocess.PIPE, shell=True)
proc = subprocess.Popen("third_party.exe", stdout=subprocess.PIPE, creationflags=subprocess.CREATE_NEW_CONSOLE)
si = subprocess.STARTUPINFO()
si.dwFlags = subprocess.STARTF_USESTDHANDLES | subprocess.STARTF_USESHOWWINDOW
proc = subprocess.Popen("third_party.exe", stdout=subprocess.PIPE, startupinfo=si)
编辑1:
在这种情况下我实际上无法使用 .communicate() 。我正在启动的应用程序会长时间运行(几天到几周)。我实际测试 .communicate() 的唯一方法是在应用程序启动后不久终止它,我认为这不会给我有效的结果。
即使是非线程版本也会失败:
import subprocess, time
from threading import Thread
proc = subprocess.Popen("third_party.exe", stdout=subprocess.PIPE, stderr=subprocess.PIPE)
print "App started, reading output..."
for line in iter(proc.stdout.readline,''):
line = line.rstrip("\r\n")
print "Got: %s" % line
编辑2:
感谢 jdi,以下工作正常:
import tempfile, time, subprocess
w = "test.txt"
f = open("test.txt","a")
p = subprocess.Popen("third_party.exe", shell=True, stdout=f,
stderr=subprocess.STDOUT, bufsize=0)
time.sleep(30)
with open("test.txt", 'r') as r:
for line in r:
print line
f.close()