[FEATURE] Add the option to restore original values for saving a modified configuration. #32
Description
I need to save a modified configuration back to the configuration file. Saving values instead of variables defeats the purpose of putting variables there in the first place. :/
I'd like to have a way to restore the original values before writing changes back to the configuration file.
I considered 'pre-loading' the file and looking for the various formats this can appear in, but that got hairy quickly. I then re-did your library in a relatively simplistic way in hopes of just grabbing the key and saving it and its value in another dict, but I can't figure out how to grab the key for the current value.
A stripped down example looks like this.
original_values = {}
def regex_resolver():
# regex built here, pretty much untouched from your code
def substitute_variable_values(value: str):
# again, match and replace ripped from your code
def load_yaml(filename):
def resolve_env_vars(loader, node):
value = loader.construct_scalar(node)
return substitute_variable_values(value)
def store_values(loader, node):
# this is where things bogged down
# I've gotten to this point, but I have no clue how to proceed
value = loader.construct_mappings(node)
# somehow, grab the key, but by this point, it's buried in the
# object and I can see it, but I can't see how to pull it out via
# code
original_values[key] = value
loader = yaml.SafeLoader
loader.add_implicit_resolver(tag, regex_resolver(), None)
loader.add_constructor(tag, resolve_env_vars)
loader.add_constructor(tag, store_values)
with open(yamlfile, 'r', encoding='utf-8') as raw:
cfg = yaml.load(raw, Loader=loader)
return cfg
# Writing the config would be easy.
def write_config(filename, data):
if original_values.keys():
data | original_values
with open(filename, 'w', encoding='utf-8') as raw:
yaml.dump(data, fh)
Though, it would be nice to include that in the library so the dev wouldn't have to remember to do that final step.