How to read /dev/log?

Question

I would like to directly access to syslog messages from Python by reading /dev/log.

My (very limited) understanding is that the correct way is to read from there is to bind a datagram socket.

import socketsock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)sock.bind('/dev/log')sock.listen(1)while True:data, addr = sock.recvfrom(1024)print(data)

Apparently /dev/log is in use:

Traceback (most recent call last):File "readlog.py", line 4, in <module>sock.bind('/dev/log')OSError: [Errno 98] Address already in use

How should I read /dev/log from Python?

EDIT: per @Barmar's comment - only one process can access /dev/log so that part is clear, the device must be clean before reading from it. sudo lsof /dev/log does not show anything.

A answer in a Java thread around this subject mentioned that syslog should be shut down before. I also tried that, lsof | grep "/dev/log" was empty but I got the error nevertheless.
Isn't it possible to have several processes reading from /dev/log?

Best Answer

Accepted Answer

There is a socket flag to set, in order to prevent this:

socket.SO_REUSEADDR

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

This flag tells the kernel to reuse a local socket in TIME_WAIT state, without waiting for its natural timeout to expire.

Ref: https://docs.python.org/3/library/socket.html

How to read /dev/log?

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