我有问题...有谁知道为什么这段代码在while循环中挂起。循环似乎没有捕获标准输出的最后一行。
working_file = subprocess.Popen(["/pyRoot/iAmACrashyProgram"], stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
line = working_file.stdout.readline()
working_file.stdout.flush()
while working_file != "" :
print(line)
line = working_file.stdout.readline()
working_file.stdout.flush()
当遇到readline()时,脚本会随着光标一样闪烁。我不明白为什么。任何人都可以解释一下
全部谢谢
乔恩
答案 0 :(得分:4)
执行非阻塞读取会帮助您吗?
import fcntl
import os
def nonBlockReadline(output):
fd = output.fileno()
fl = fcntl.fcntl(fd, fcntl.F_GETFL)
fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
try:
return output.readline()
except:
return ''
working_file = subprocess.Popen(["/pyRoot/iAmACrashyProgram"], stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
line = nonBlockReadline(working_file.stdout)
working_file.stdout.flush()
while working_file != "" :
print(line)
line = nonBlockReadline(working_file.stdout)
working_file.stdout.flush()
我不确定你到底想要做什么,但这会更好吗?它只读取所有数据,而不是一次只读取一行。它对我来说更具可读性。
import fcntl
import os
def nonBlockRead(output):
fd = output.fileno()
fl = fcntl.fcntl(fd, fcntl.F_GETFL)
fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
try:
return output.read()
except:
return ''
working_file = subprocess.Popen(["/pyRoot/iAmACrashyProgram"], stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
stdout = ''
while working_file.poll() is None:
stdout += nonBlockRead(working_file.stdout)
# we can probably save some time and just print it instead...
#print(stdout)
stdout = stdout.splitlines()
for line in stdout:
print(line)
编辑:一个更适合您的用例的通用脚本:
import fcntl
import os
def nonBlockRead(output):
fd = output.fileno()
fl = fcntl.fcntl(fd, fcntl.F_GETFL)
fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
try:
return output.read()
except:
return ''
working_file = subprocess.Popen(["/pyRoot/iAmACrashyProgram"], stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
while working_file.poll() is None:
stdout = nonBlockRead(working_file.stdout)
# make sure it returned data
if stdout:
# process data
working_file.stdin.write(something)