Python config parser that supports section inheritance?

Question

I'm looking for an ini style config parser in Python that supports section inheritance similar to what Zend_Config_Ini does in PHP.

Does such a module exist or will I need to roll my own?

score 20 · Answer 1 · answered Jun 30 '11 at 08:53

20

Python's ConfigParser can load multiple files. Files read later on can override settings from the first file.

For example, my application has database settings in its internal default configuration file:

[database]
server = 127.0.0.1
port = 1234
...

I override these on a different server with a "environment.ini" file containing the same section but different values:

[database]
server = 192.168.0.12
port = 2345
...

In Python:

import os
from ConfigParser import ConfigParser
dbconf = ConfigParser()
dbconf.readfp(open('default.ini'))
if os.path.exists('environment.ini'):
    dbconf.readfp(open('environment.ini'))
dbconf.get('database', 'server') # Returns 192.168.0.12

answered Jun 30 '11 at 08:53

tuomur

6,888
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37

1

Thanks for the info. Unfortunately this won't work for me due to a business requirement of having one master file that will be parsed in a number of programming languages. Looking like I'll need to implement myself. – Maascamp Jul 01 '11 at 23:21
3

Yes, I implemented one that met my requirements (Zend_Config_Ini style) and converts to python native types where possible. See here [https://bitbucket.org/maascamp/pyconfigini](https://bitbucket.org/maascamp/pyconfigini). Hope it helps. – Maascamp Mar 15 '12 at 00:43
1

@Maascamp Great Job! I was looking for a python ini parse such as Zend_Config_Ini, you should answer your own question and post your solution :) – dextervip Aug 13 '12 at 06:16

score 1 · Answer 2 · edited Sep 20 '13 at 13:09

Here's what I used. extended_get method is what you need - it supports hierarchical sections.

import re
import io
import ConfigParser

class ZendConfigParser(ConfigParser.ConfigParser):
    def extended_get(self, section, key):
        if self.has_option(section, key):
            return self.get(section, key)
        else:
            orig_section, parent_section = self._get_orig_section(section)
            if orig_section != None:
                if self.has_option(orig_section,key):
                    return self.get(orig_section,key)
                else:
                    return self.extended_get(parent_section,key)
            else:
                return None



    def _get_orig_section(self, zend_section):
        orig_section = None
        parent_section = None
        for section in self.sections():
            if re.search(r'^[ \t]*' + zend_section + '\\b', section) != None:
                orig_section = section
                #look for a parent section
                match = re.match(r'\w+[ \t]*:[ \t]*(\w+)$', section)
                if match != None:
                    parent_section = match.groups()[0]
                break

        return (orig_section, parent_section)

config = ZendConfigParser()
config.read(file)
print(config.extended_get('production', 'database.params.host'))

thanks Roman! Somehow the old method name sneaked into the code :) — xvga, Apr 14 '12 at 06:38

score 0 · Answer 3 · answered Feb 25 '12 at 20:11

I also did not find any ready solution. To solve it, I adapted the get function of ConfigParser to search in the child section and afterwards in the parent section:

config = SafeConfigParser()
config.read(filenames)
required_environment = "mysection"

# determine fallback requirement in case parameter is not found in required environment
fallback_environment = "default"
# loop through all sections of config files
for environment in config.sections():
    # check whether we find an inheritance based on the required section
    if re.search(required_environment + " *: *\w+", environment):
        # found inheritance, take parent as fallback section
        fallback_environment = re.sub(required_environment + r" : (\w+)", r"\1", environment)
        # take this name as requested section
        required_environment = environment

# override get method
_config_parser_get = config.get
def myConfigParserGet(id):
    # check different sections for desired value
    if config.has_option(required_environment, id):
        return _config_parser_get(required_environment, id)
    else:
        return _config_parser_get(fallback_environment, id)

config.get = myConfigParserGet

Restrictions:

only read-only access to config supported
only one level of inheritance

Python config parser that supports section inheritance?

3 Answers3