Reading a configuration file in Python (storing/reading nested data with ConfigParser)

Question

I am writing a list processing script that needs to read configuration data about each item in the list. The configuration data is best represented as a nested tree.

I would normally have used YAML for storing the data - but I think that using ConfigParser would be a more Pythonic approach - and make the script more 'transparent' to other Python coders - since a surprising number of people are not familiar with the YAML format.

I have had a very quick look at the configParser documentation , but I have not been able to ascertain whether it can deal with nested data.

My configuration data will have the following structure:

<markers>
    <marker>
        <date></date>
        <value></value>
    </marker>
</markers>
<items>
    <item>
        <start></start>
        <end></end>
        <mcc>
           <chg>
                <date></date>
                <ival></ival>
                <fval></fval>
           </chg>
        </mcc>
    </item>
</items>

Can I use ConfigParser to read/(write ?) this kind of nested data in a config file? (I'm more interested in being able to read than writing the config file. I don't mind manually writing the config file if necessary).

Answer 1

No, configparser doesn't support nesting. You could look at configObj instead. It's mature and quite widely used.

Answer 2

As per your xml data you need section and subsection. So you can use the ConfigParser but you have to give sub section with some meaning like

[markers]
[markers.marker]
date=''
value=''

[items]
[items.item]
start=''
end=''
[items.item.mcc]
[items.item.mcc.chg]
date=''
ival=''
fval=''

Then you have to override the getsection function to get the nested data.

Answer 3

TOML configuration files follow a similar syntax to INI files and allow for nested structures. See the official specification here and the corresponding python library here .

Example:

>>> import toml
>>> toml_string = """
... # This is a TOML document.
...
... title = "TOML Example"
...
... [owner]
... name = "Tom Preston-Werner"
... dob = 1979-05-27T07:32:00-08:00 # First class dates
...
... [database]
... server = "192.168.1.1"
... ports = [ 8001, 8001, 8002 ]
... connection_max = 5000
... enabled = true
...
... [servers]
...
...   # Indentation (tabs and/or spaces) is allowed but not required
...   [servers.alpha]
...   ip = "10.0.0.1"
...   dc = "eqdc10"
...
...   [servers.beta]
...   ip = "10.0.0.2"
...   dc = "eqdc10"
...
... [clients]
... data = [ ["gamma", "delta"], [1, 2] ]
...
... # Line breaks are OK when inside arrays
... hosts = [
...   "alpha",
...   "omega"
... ]
... """
>>> parsed_toml = toml.loads(toml_string)