Trying to use global variables for referencing directories in Python 2.5

I am writing a small utility that reads a number of print files to extract out financial data, and then build a spreadsheet populating the data in specific cells.

I have it working, but it's not elegant and certainly not what you would call Pythonic, so I am rewriting to make it more efficient and improve my Python skills.

First hurdle...

I'd like to use a procedure to write out to a log-file but I'm not sure I've got my head around how global functions and variables work in python.

Reading the question https://stackoverflow.com/questions/13034496/using-global-variables-between-files-in-python suggests that I need to use a separate file to hold the global variables, so I have this in config.py:

def init():
    global DEBUG
    DEBUG = True
    global directoryBase
    directoryBase = 'C:/Users/djehan1/workspace/PeriodEnd/'
    global directoryLogFile
    directoryLogFile = dirBase + ''
    global directoryReportSource
    directoryReportSource = directoryBase + 'reports/'
    global directoryExcelOutput
    directoryExcelOutput = directoryBase + 'output/'
    global directoryGeneralLedger
    directoryGeneralLedger = directoryBase + 'resource/'
    global directoryListOfReports
    directoryListOfReports = directoryBase + 'resource/'
    global gl_reporting_year
    gl_reporting_year = ''
    global gl_reporting_period
    gl_reporting_period = ''
    global reportType
    reportType=''
    global logFileHandle
    logFileHandle=None

I then have a functions.py file that has the following procedure for writing out to the log file:

def write_log(line):
    if line.strip() != '':
        import datetime
        now = datetime.datetime.now()
        config.logFileHandle.write(now.strftime('%H:%M:%S') + ' - ' + line + '\n')
    else:
        config.logFileHandle.write('\n')

Then in my main.py I have:

```
import config
import datetime

from functions import *
config.init()

config.logFileHandle = open(config.directoryLogFile + 'period_end_p

"Have I understood the concept of the config file and is this the best way to implement?"

Take everything in this:

def init():

and remove the global declarations, delete the def line, and dedent the code. Then there will be no need to "initialize" the module.


"Is there a way to have the datetime available to all sub modules?"

Import the module into the namespace of the modules that you use it in. Do all your imports at the top of the file. The below is wrong:

def write_log(line):
    if line.strip() != '':
        import datetime
        now = datetime.datetime.now()
        config.logFileHandle.write(now.strftime('%H:%M:%S') + ' - ' + line + '\n')
    else:
        config.logFileHandle.write('\n')

Instead of this function, you should use the logging module.

import logging
logging.basicConfig(level=logging.DEBUG, # or other level
                    filename='myfilename.log',
                    format='%(asctime)s %(message)s',
                    datefmt='%m/%d/%Y %I:%M:%S %p',
                    )
logger = logging.getLogger(__name__)
logger.info('here is some info')
logger.debug('here is a debug statement')
logger.warn('here is a warning')
logger.error('here is an error')
logger.critical('a critical problem happened')

and you'll get the following:

$ cat myfilename.log 
09/25/2015 12:25:05 AM here is some info
09/25/2015 12:25:05 AM here is a debug statement
09/25/2015 12:25:05 AM here is a warning
09/25/2015 12:25:05 AM here is an error
09/25/2015 12:25:05 AM a critical problem happened

"Is this the way to do this?"

No, do not import *, do not "initialize" modules, do not write your own logger. You can have globals in a config module, though.

StackExchange Code Review Q#105673, answer score: 4