Adding new section in config file without overwriting it using ConfigParser

Question

I am writing a code in python. I have a confg file with following data:

[section1]
name=John
number=3

I am using ConfigParser module to add another section in this already existing confg file without overwriting it. But when I use below code:

config = ConfigParser.ConfigParser()
config.add_section('Section2')
config.set('Section2', 'name', 'Mary')
config.set('Section2', 'number', '6')
with open('~/test/config.conf', 'w') as configfile:
    config.write(configfile) 

it overwrites the file. I do not want to delete the previous data. Is there any way I can just add one more section? If I try to get and write the data of previous sections first, then it will become untidy as the number of sections will increase.

Answer 1

Open the file in append mode instead of write mode. Use 'a' instead of 'w'.

Example:

config = configparser.RawConfigParser({'num threads': 1})
config.read('path/to/config')
try:
    NUM_THREADS = config.getint('queue section', 'num threads')
except configparser.NoSectionError:
    NUM_THREADS = 1
    config_update = configparser.RawConfigParser()
    config_update.add_section('queue section')
    config_update.set('queue section', 'num threads', NUM_THREADS)

    with open('path/to/config', 'ab') as f:
        config_update.write(f)