python 有没实时文件监控的 tail -F？

[masterzh01]

tail -F 的源码是采用 inotify + select 方式来实现

python 的 pyinotify 库对 inotify 进行了封装，但貌似性能不是很好。

实现 tail-F: https://github.com/masterzh01/tail-F

[necomancer]

from sys import argv
import collections


o = open(argv[1], 'r')
print(''.join(collections.deque(o, 5)).strip('\n')) # last 5 lines
o.seek(0,2) # jump to last line
while 1:
....line = o.readline()
....if line:
........print(line.strip('\n'))

就可以了吧……

[masterzh01]

@necomancer 不行， cpu ， rotate.....（ tail -F ）

[hasdream]

```
import time

import time
def follow(thefile):
thefile.seek(0,2) # Go to the end of the file
while True:
line = thefile.readline()
if not line:
time.sleep(0.1) # Sleep briefly
continue
yield line

# Example use
if __name__ == '__main__':
logfile = open("access-log")
for line in follow(logfile):
print line,

```

[necomancer]

@masterzh01 CPU usage 问题加上 sleep 就行：

from sys import argv
import collections
import time

o = open(argv[1], 'r')
print(''.join(collections.deque(o, 5)).strip('\n')) # last 5 lines
o.seek(0,2) # jump to last line
while 1:
....line = o.readline()
....if not line:
........time.sleep(0.1)
........continue
....print(line.strip('\n'))

[masterzh01]

@hasdream @necomancer 事件驱动方式会更好些？

[hasdream]

@masterzh01 如果用事件来做基本没延迟 不过要复杂点还要对事件处理