我写了一个 python 脚本来监视一些网络资源的状态,如果你愿意的话,这是一个无限的 pinger。它会永远 ping 相同的 3 个节点,直到收到键盘中断。我尝试使用 tee 将程序的输出重定向到文件,但它不起作用:
λ sudo ./pingster.py
15:43:33 node1 SUCESS | node2 SUCESS | node3 SUCESS
15:43:35 node1 SUCESS | node2 SUCESS | node3 SUCESS
15:43:36 node1 SUCESS | node2 SUCESS | node3 SUCESS
15:43:37 node1 SUCESS | node2 SUCESS | node3 SUCESS
15:43:38 node1 SUCESS | node2 SUCESS | node3 SUCESS
^CTraceback (most recent call last):
File "./pingster.py", line 42, in <module>
main()
File "./pingster.py", line 39, in main
sleep(1)
KeyboardInterrupt
λ sudo ./pingster.py | tee ping.log
# wait a few seconds
^CTraceback (most recent call last):
File "./pingster.py", line 42, in <module>
main()
File "./pingster.py", line 39, in main
sleep(1)
KeyboardInterrupt
λ file ping.log
ping.log: empty
我正在使用 colorama 进行输出,我认为这可能会导致问题,但我在导入 colorama 之前尝试打印一些内容,并且文件仍然是空的。我在这里做错了什么?
编辑:这是我正在使用的Python文件
#!/home/nate/py-env/ping/bin/python
from __future__ import print_function
from datetime import datetime
from collections import OrderedDict
from time import sleep
import ping
import colorama
def main():
d = {
'node1': '10.0.0.51',
'node2': '10.0.0.50',
'node3': '10.0.0.52',
}
addresses = OrderedDict(sorted(d.items(), key=lambda t: t[0]))
colorama.init()
while True:
status = []
time = datetime.now().time().strftime('%H:%M:%S')
print(time, end='\t')
for location, ip_address in addresses.items():
loss, max_time, avg_time = ping.quiet_ping(ip_address, timeout=0.5)
if loss < 50:
status.append('{0} SUCESS'.format(location))
else:
status.append(
'{}{} FAIL{}'.format(
colorama.Fore.RED,
location,
colorama.Fore.RESET,
)
)
print(' | '.join(status))
sleep(1)
if __name__ == '__main__':
main()
这是重现问题的更简单方法:
$ cat foo.py
from time import sleep
while True:
sleep(2)
print "hello"
$ python foo.py
hello
hello
(...)
$ python foo.py | tee log
(no output)
发生这种情况是因为
python
当它不是终端时缓冲标准输出。取消缓冲的最简单方法是使用 python -u
:
$ python -u foo.py | tee log
hello
hello
(...)
您还可以将 shebang 设置为
#!/usr/bin/python -u
(这不适用于 env
)。