borgmatic/borgmatic/config/validate.py

74 lines
2.5 KiB
Python

import logging
import sys
import warnings
import pkg_resources
import pykwalify.core
import pykwalify.errors
from ruamel import yaml
def schema_filename():
'''
Path to the installed YAML configuration schema file, used to validate and parse the
configuration.
'''
return pkg_resources.resource_filename('borgmatic', 'config/schema.yaml')
class Validation_error(ValueError):
'''
A collection of error message strings generated when attempting to validate a particular
configurartion file.
'''
def __init__(self, config_filename, error_messages):
self.config_filename = config_filename
self.error_messages = error_messages
def parse_configuration(config_filename, schema_filename):
'''
Given the path to a config filename in YAML format and the path to a schema filename in
pykwalify YAML schema format, return the parsed configuration as a data structure of nested
dicts and lists corresponding to the schema. Example return value:
{'location': {'source_directories': ['/home', '/etc'], 'repository': 'hostname.borg'},
'retention': {'keep_daily': 7}, 'consistency': {'checks': ['repository', 'archives']}}
Raise FileNotFoundError if the file does not exist, PermissionError if the user does not
have permissions to read the file, or Validation_error if the config does not match the schema.
'''
try:
schema = yaml.round_trip_load(open(schema_filename))
except yaml.error.YAMLError as error:
raise Validation_error(config_filename, (str(error),))
# pykwalify gets angry if the example field is not a string. So rather than bend to its will,
# simply remove all examples before passing the schema to pykwalify.
for section_name, section_schema in schema['map'].items():
for field_name, field_schema in section_schema['map'].items():
field_schema.pop('example')
validator = pykwalify.core.Core(source_file=config_filename, schema_data=schema)
parsed_result = validator.validate(raise_exception=False)
if validator.validation_errors:
raise Validation_error(config_filename, validator.validation_errors)
return parsed_result
def display_validation_error(validation_error):
'''
Given a Validation_error, display its error messages to stderr.
'''
print(
'An error occurred while parsing a configuration file at {}:'.format(
validation_error.config_filename
),
file=sys.stderr,
)
for error in validation_error.error_messages:
print(error, file=sys.stderr)