is this a bug?

[allan-avatar1]

hey, great util. thanks. i notice that in follow(self,delay=1.0) there is the following code:

            if line[-1] in self.line_terminators:
                line = line[:-1]
                if line[-1:] == '\r\n' and '\r\n' in self.line_terminators:
                    # found crlf
                    line = line[:-1]

but if this is NOT true, then that means we have a line that does not end in a line_terminator. this happens when you've reached the end of a file that you are tailing and the producer of the file is flushing midway through a line.

I would imagine you need to do the following:

            if line[-1] in self.line_terminators:
                line = line[:-1]
                if line[-1:] == '\r\n' and '\r\n' in self.line_terminators:
                    # found crlf
                    line = line[:-1]
            else:
                #Got a partial line
                trailing=True;self.seek(where);time.sleep(delay); continue

*My b if this format is annoying. I'm far too lazy to create pull requests and I have no idea how markdown works. 5min is about all the time I have committed to this bug report. Peace

[six8]

Wouldn't it just wait till a new line is flushed as implemented?

[bakerkj]

This appears to fail in the way that jl45621 suggests.

An example that triggers the problem.

Writer:
import time
fout = open("/tmp/log", "w")
while(True):
fout.write("abcdefghijklmn")
fout.flush()
time.sleep(1)
fout.write("opqrstuvwxyz\n")
fout.flush()

Reader:
import tailer
import time

def process_line(line):
if line != "abcdefghijklmnopqrstuvwxyz":
print line

fin = open("/tmp/log", "r")
tl = tailer.Tailer(fin)
tl.seek_end()
for line in tl.follow(0.1):
process_line(line)

If this were working correctly the reader should never yield output. However it does because the tail.follow(0.1) yields partial lines that are not line terminated.

[frozflame]

The essential hack using this package might be

Tailer.line_terminators = []