ANN: New configuration module released

Vinay Sajip vinay_sajip at yahoo.co.uk
Wed Nov 3 15:50:17 CET 2004


I've just made available the first general release of a configuration
module for Python. It has grown out of the need to make configuration
easier and more powerful (for developers and end users) than
ConfigParser.

It's one of the implementations which could be considered in the
ConfigParser shootout, mentioned on the Python Wiki at

http://www.python.org/moin/ConfigParserShootout

What Does It Do?
================
The config module allows you to implement a hierarchical configuration
scheme with support for mappings and sequences, cross-references
between one part of the configuration and another, the ability to
flexibly access real Python objects, facilities for configurations to
include and cross-reference one another, simple expression evaluation
and the ability to change, save, cascade and merge configurations.

This module has been developed on python 2.3 but should work on
version 2.2 or greater. A test suite using unittest is included in the
distribution.

A very simple configuration file (simple.cfg):

# starts here
message: Hello, world!
#ends here

a very simple program to use it:

from config import Config

cfg = Config(file('simple.cfg'))
print cfg.message

results in:

Hello, world!

Configuration files are key-value pairs, but the values can be
containers that contain further values
A simple example - with the example configuration file: 

messages:
[
  {
    stream : `sys.stderr`
    message: 'Welcome'
    name: 'Harry'
  }
  {
    stream : `sys.stdout`
    message: 'Welkom'
    name: 'Ruud'
  }
  {
    stream : $messages[0].stream
    message: 'Bienvenue'
    name: Yves
  }
]

a program to read the configuration would be:

from config import Config

f = file('simple.cfg')
cfg = Config(f)
for m in cfg.messages:
    s = '%s, %s' % (m.message, m.name)
    try:
        print >> m.stream, s
    except IOError, e:
        print e

which, when run, would yield the console output:

Welcome, Harry
Welkom, Ruud
Bienvenue, Yves

The above example just scratches the surface. There's more information
about this module available at

http://www.red-dove.com/python_config.html

Comprehensive API documentation is available at

http://www.red-dove.com/config/index.html

As always, your feedback is most welcome (especially bug reports,
patches and suggestions for improvement). Enjoy!

Cheers

Vinay Sajip
Red Dove Consultants Ltd.



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