configlines 0.2

Add line number information to ConfigParser options

Description

This module is an extension to Python’s standard configparser module that adds file and line number information to each stored option. This is primarily useful in reporting error messages: you can point your user to exactly where a bad value occurred:

try:
    timeout = config.getint('connection', 'retry')
except ValueError:
    filename, line = config.get_location('connection', 'retry')
    logging.error("retry must be an integer (%s:%d)", filename, line)
    ...

This package is compatible with both Python 2 and 3.

Installation

Install with pip:

$ pip install configlines

Usage

Given the following two configuration files:

# Line one of data1.cfg
[some_section]
foo = 1

[DEFAULT]
bar = 2

# Line one of data2.cfg
[some_section]
baz = 3

You can read and manipulate them exactly the same as the standard module:

>>> from configlines import ConfigParser
>>> cfg = ConfigParser()
>>> cfg.read(['data1.cfg', 'data2.cfg'])
>>> cfg.get('some_section', 'foo')
'1'

You can also access file and line information:

>>> cfg.get_location('some_section', 'foo')
('data1.cfg', 3)
>>> cfg.get_location('some_section', 'bar')
('data1.cfg', 6)
>>> cfg.get_location('some_section', 'baz')
('data2.cfg', 3)

In addition to get_location, this module also provides get_line and get_filename functions for convenience.

If an option didn’t come from a file, (i.e., you set it programmatically,) then line number information will not be present:

>>> cfg.set('some_section', 'qwerty', '1234')
>>> cfg.get_location('some_section', 'qwerty')
None

Overwriting options programmatically will erase line number information:

>>> cfg.get_location('some_section', 'foo')
('data1.cfg', 3)
>>> cfg.set('some_section', 'foo', '1234')
>>> cfg.get_location('some_section', 'foo')
None

Line number information can be set explicitly:

>>> cfg.set('some_section', 'foo', '1234', location=('somefile.cfg',10))
>>> cfg.get_location('some_section', 'foo')
('somefile.cfg', 10)
>>> cfg.set('some_section', 'foo', '1234', location='preserve')
>>> cfg.get_location('some_section', 'foo')
('somefile.cfg', 10)
>>> cfg.set_location('some_section', 'foo', ('otherfile.cfg', 50))
>>> cfg.get_location('some_section', 'foo')
('otherfile.cfg', 50)