borgmatic/borgmatic/config/override.py

79 lines
2.3 KiB
Python

import io
import ruamel.yaml
def set_values(config, keys, value):
'''
Given a hierarchy of configuration dicts, a sequence of parsed key strings, and a string value,
descend into the hierarchy based on the keys to set the value into the right place.
'''
if not keys:
return
first_key = keys[0]
if len(keys) == 1:
config[first_key] = value
return
if first_key not in config:
config[first_key] = {}
set_values(config[first_key], keys[1:], value)
def convert_value_type(value):
'''
Given a string value, determine its logical type (string, boolean, integer, etc.), and return it
converted to that type.
Raise ruamel.yaml.error.YAMLError if there's a parse issue with the YAML.
'''
return ruamel.yaml.YAML(typ='safe').load(io.StringIO(value))
def parse_overrides(raw_overrides):
'''
Given a sequence of configuration file override strings in the form of "section.option=value",
parse and return a sequence of tuples (keys, values), where keys is a sequence of strings. For
instance, given the following raw overrides:
['section.my_option=value1', 'section.other_option=value2']
... return this:
(
(('section', 'my_option'), 'value1'),
(('section', 'other_option'), 'value2'),
)
Raise ValueError if an override can't be parsed.
'''
if not raw_overrides:
return ()
parsed_overrides = []
for raw_override in raw_overrides:
try:
raw_keys, value = raw_override.split('=', 1)
parsed_overrides.append((tuple(raw_keys.split('.')), convert_value_type(value),))
except ValueError:
raise ValueError(
f"Invalid override '{raw_override}'. Make sure you use the form: SECTION.OPTION=VALUE"
)
except ruamel.yaml.error.YAMLError as error:
raise ValueError(f"Invalid override '{raw_override}': {error.problem}")
return tuple(parsed_overrides)
def apply_overrides(config, raw_overrides):
'''
Given a configuration dict and a sequence of configuration file override strings in the form of
"section.option=value", parse each override and set it the configuration dict.
'''
overrides = parse_overrides(raw_overrides)
for (keys, value) in overrides:
set_values(config, keys, value)