Python logging config file modules and packages

Question

I am tearing my hair out.

I need a syslog handler.

I found this: at a StackOverflow page and found the approach works just fine standalone, communicates as it should with this system's syslog.

However, I can't figure out how to refer to it in my logging config file. I am using Python 2.6.6 so dict config is not available to me. I have to use file configuration. According to docs the class name has to be either relative to logging or a full specification from the python path.

Here is the section of my config file:

[handler_syslog]
class=logext.HDSysLogHandler
level=WARN
formatter=timestamp
args=(7, )

logext is a package located one level deeper than my main.

It contains 3 python files and compiled files:

[logext]$ ls -al
total 32
drwxr-x---. 2 sc1478 dev 4096 Apr 25 11:50 .
drwxr-x---. 3 sc1478 dev 4096 Apr 25 11:50 ..
-rw-r-----. 1 sc1478 dev  243 Apr 25 11:50 HDSysLogHandler.py
-rw-r-----. 1 sc1478 dev  630 Apr 25 11:50 HDSysLogHandler.pyc
-rw-r-----. 1 sc1478 dev    2 Apr 25 11:50 __init__.py
-rw-r-----. 1 sc1478 dev  132 Apr 25 11:50 __init__.pyc
-rw-r-----. 1 sc1478 dev 2426 Apr 25 11:50 syslog_bridge.py
-rw-r-----. 1 sc1478 dev 2386 Apr 25 11:50 syslog_bridge.pyc

init.py is blank, just to make a package.

syslog.bridge.py is basically the file referred to above, with a small change to the constructor to make it more flexible and work with Python 2.6

class SysLogLibHandler(logging.Handler):
    ...
    def __init__(self, identifier, n):
        try:
            syslog.openlog(identifier, syslog.LOG_PID, self.FACILITY[n])
        except Exception , err:
            print err
            raise

        # We got it
        logging.Handler.__init__(self)

finally HDSysLogHandler.py is as follows:

from syslog_bridge import SysLogLibHandler

class HDSysLogHandler(SysLogLibHandler):

    def __init__(self, local_facility):
        SysLogLibHandler.__init__(self, "hdaudio", local_facility)

The relevant section of the main module is:

import logging
import logging.config
import logext
...
logging.config.fileConfig('logging.conf')

When my main app is run, I get this:

Traceback (most recent call last):
  File "Main.py", line 23, in <module>
    logging.config.fileConfig('logging.conf')
  File "/usr/lib64/python2.6/logging/config.py", line 84, in fileConfig
    handlers = _install_handlers(cp, formatters)
  File "/usr/lib64/python2.6/logging/config.py", line 162, in _install_handlers
    h = klass(*args)
TypeError: 'module' object is not callable

What is this trying to tell me? WHAT module is not callable? Who's trying to "call it"?

What is the RIGHT way to locate a home-brewed logging handler and specify it in a logging configuration file?

Answer 1

I think you are seeing this error because

class=logext.HDSysLogHandler

specifies the class to be logext.HDSysLogHandler, which is a module, not a class. Instead try

class=logext.HDSysLogHandler.HDSysLogHandler

since this specifies the HDSysLogHandler class which is inside the logext.HDSysLogHandler module.

Answer 2

You shall start with platform specific documentation first :-)

Python 2.6 is providing SysLogHandler

If you like using dict configured logging configuration, you may use logutils package, which provides dictionary based configuration usable in Python 2.6.

I used in logutils in Python 2.6 a lot and was very happy with it. Later move to Python 2.7 was very easy.