Tailing a log file?

[Kenji Noguchi]

something like this? unix tail command does more fancy stuff
like it waits for timeout, and check if the file is truncated
or depending on incoming data it sleeps seconds , etc etc.

#!/usr/bin/env python
import sys, select

while True:
    ins, outs, errs = select.select([sys.stdin],[],[])
    for i in ins:
        print i.readline()


2007/6/22, Evan Klitzke <evan at yelp.com>:
> On 6/22/07, Evan Klitzke <evan at yelp.com> wrote:
> > Everyone,
> >
> > I'm interested in writing a python program that reads from a log file
> > and then executes actions based on the lines. I effectively want to
> > write a loop that does something like this:
> >
> > while True:
> >     log_line = log_file.readline()
> >     do_something(log_line)
> >
> > Where the readline() method blocks until a new line appears in the
> > file, unlike the standard readline() method which returns an empty
> > string on EOF. Does anyone have any suggestions on how to do this?
> > Thanks in advance!
>
> I checked the source code for tail and they actually poll the file by
> using fstat and sleep to check for changes in the file size. This
> didn't seem right so I thought about it more and realized I ought to
> be using inotify. So I guess I answered my own question.
>
> --
> Evan Klitzke <evan at yelp.com>
> --
> http://mail.python.org/mailman/listinfo/python-list
>