How to configure logging to syslog in Python?

Question

I can't get my head around Python's logging module. My needs are very simple: I just want to log everything to syslog. After reading documentation I came up with this simple test script:

import logging
import logging.handlers

my_logger = logging.getLogger('MyLogger')
my_logger.setLevel(logging.DEBUG)

handler = logging.handlers.SysLogHandler()

my_logger.addHandler(handler)

my_logger.debug('this is debug')
my_logger.critical('this is critical')

But this script does not produce any log records in syslog. What's wrong?

Answer 1

Is your syslog.conf set up to handle facility=user?

You can set the facility used by the python logger with the facility argument, something like this:

handler = logging.handlers.SysLogHandler(facility=SysLogHandler.LOG_DAEMON)

Answer 2

Piecing things together from here and other places, this is what I came up with that works on unbuntu 12.04 and centOS6

Create an file in /etc/rsyslog.d/ that ends in .conf and add the following text

local6.*        /var/log/my-logfile

Restart rsyslog, reloading did NOT seem to work for the new log files. Maybe it only reloads existing conf files?

sudo restart rsyslog

Then you can use this test program to make sure it actually works.

import logging, sys
from logging import config

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'verbose': {
            'format': '%(levelname)s %(module)s P%(process)d T%(thread)d %(message)s'
            },
        },
    'handlers': {
        'stdout': {
            'class': 'logging.StreamHandler',
            'stream': sys.stdout,
            'formatter': 'verbose',
            },
        'sys-logger6': {
            'class': 'logging.handlers.SysLogHandler',
            'address': '/dev/log',
            'facility': "local6",
            'formatter': 'verbose',
            },
        },
    'loggers': {
        'my-logger': {
            'handlers': ['sys-logger6','stdout'],
            'level': logging.DEBUG,
            'propagate': True,
            },
        }
    }

config.dictConfig(LOGGING)


logger = logging.getLogger("my-logger")

logger.debug("Debug")
logger.info("Info")
logger.warn("Warn")
logger.error("Error")
logger.critical("Critical")

Answer 3

I found the syslog module to make it quite easy to get the basic logging behavior you describe:

import syslog
syslog.syslog("This is a test message")
syslog.syslog(syslog.LOG_INFO, "Test message at INFO priority")

There are other things you could do, too, but even just the first two lines of that will get you what you've asked for as I understand it.

Answer 4

You can also add a file handler or rotating file handler to send your logs to a local file: http://docs.python.org/2/library/logging.handlers.html