Default Section Values in ConfigParser

[mwt]

I want to set default values for a ConfigParser. So far, its job is
very small, so there is only one section heading, ['Main']. Reading the
docs, I see that in order to set default values in a ConfigParser, you
initialize it with a dictionary or defaults. However, I'm not quite
sure of the syntax to add the section headings in to the dictionary of
defaults. For now, I'm doing it like this:

default_values = {'username' : 'put username here',
'teamnumber': 'team number here',
'update_interval' : 'update interval'}
self.INI = ConfigParser.ConfigParser(default_values)
self.INI.add_section('Main')

This works, but clearly won't last beyond the adding of a second
section. What is the correct way to initialize it with a full
dictionary of defaults, including section names?

Thanks.

 

[Terry Hancock]

I want to set default values for a ConfigParser. So far,
its job is very small, so there is only one section
heading, ['Main']. Reading the docs, I see that in order
to set default values in a ConfigParser, you initialize it
with a dictionary or defaults.

You know, I never noticed that, but there is another way.

I used a multi-line string constant with the same syntax
as the original file, and just fed that in as the first
source (this is particularly easy, so I think it must have
been intended). Slightly snipped version of my code for
this:

default_cfg = StringIO("""\
[VARIMAGE]
V1_COMPATIBILITY: ON

[SECURITY]
MAX_OPERATORS: 0
""")

# Look for varimage.cfg in 3 possible locations:
config = ConfigParser.ConfigParser()
config.readfp(default_cfg)
config.read(['/etc/varimage.cfg',
os.path.expandvars('${INSTANCE_HOME}/varimage.cfg'),
os.path.join(pkghome, 'varimage.cfg') ])

 

[mwt]

Thanks, Terry. That's an interesting way to go about it.

 

[Fuzzyman]

I want to set default values for a ConfigParser. So far, its job is
very small, so there is only one section heading, ['Main']. Reading the
docs, I see that in order to set default values in a ConfigParser, you
initialize it with a dictionary or defaults. However, I'm not quite
sure of the syntax to add the section headings in to the dictionary of
defaults. For now, I'm doing it like this:

default_values = {'username' : 'put username here',
'teamnumber': 'team number here',
'update_interval' : 'update interval'}
self.INI = ConfigParser.ConfigParser(default_values)
self.INI.add_section('Main')

This works, but clearly won't last beyond the adding of a second
section. What is the correct way to initialize it with a full
dictionary of defaults, including section names?

An alternative approach is to use `ConfigObj
<http://www.voidspace.org.uk/python/configobj.html>`_. It has two ways
of specifying default values.

The first way is to provide a configspec. This is a schema (that looks
very like a config file itself) that specifies the type (and paramater
bounds if you want) for each member. It can also include a default
value.

Simpler (although without the benefit of validation and type
conversion) is to use the ``merge`` method which is a recursive update.
(Although for config files that are a maximum of one section deep, the
dictionary method ``update`` will do the same job).

default_values = {'username' : 'put username here',
'teamnumber': 'team number here',
'update_interval' : 'update interval'}
user_values = ConfigObj(filename)
cfg = ConfigObj(default_values)
cfg.merge(user_values)

Note that for a config file with only a few values in it, ConfigObj
doesn't force you to use a section if it's not needed. To put your
default values into a 'Main' section you would actually do :

default_values = { 'Main': {'username' : 'put username here',
'teamnumber': 'team number here',
'update_interval' : 'update interval'}
}
#
user_values = ConfigObj(filename)
cfg = ConfigObj(default_values)
cfg.merge(user_values)

All the best,

Fuzzyman
http://www.voidspace.org.uk/python/index.shtml