forked from borgmatic-collective/borgmatic
110 lines
4.1 KiB
Python
110 lines
4.1 KiB
Python
import logging
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import pkg_resources
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import pykwalify.core
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import pykwalify.errors
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from ruamel import yaml
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logger = logging.getLogger(__name__)
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def schema_filename():
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'''
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Path to the installed YAML configuration schema file, used to validate and parse the
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configuration.
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'''
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return pkg_resources.resource_filename('borgmatic', 'config/schema.yaml')
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class Validation_error(ValueError):
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'''
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A collection of error message strings generated when attempting to validate a particular
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configurartion file.
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'''
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def __init__(self, config_filename, error_messages):
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self.config_filename = config_filename
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self.error_messages = error_messages
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def __str__(self):
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'''
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Render a validation error as a user-facing string.
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'''
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return 'An error occurred while parsing a configuration file at {}:\n'.format(
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self.config_filename
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) + '\n'.join(self.error_messages)
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def apply_logical_validation(config_filename, parsed_configuration):
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'''
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Given a parsed and schematically valid configuration as a data structure of nested dicts (see
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below), run through any additional logical validation checks. If there are any such validation
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problems, raise a Validation_error.
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'''
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archive_name_format = parsed_configuration.get('storage', {}).get('archive_name_format')
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prefix = parsed_configuration.get('retention', {}).get('prefix')
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if archive_name_format and not prefix:
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raise Validation_error(
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config_filename,
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('If you provide an archive_name_format, you must also specify a retention prefix.',),
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)
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location_repositories = parsed_configuration.get('location', {}).get('repositories')
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check_repositories = parsed_configuration.get('consistency', {}).get('check_repositories', [])
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for repository in check_repositories:
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if repository not in location_repositories:
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raise Validation_error(
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config_filename,
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(
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'Unknown repository in the consistency section\'s check_repositories: {}'.format(
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repository
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),
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),
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)
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consistency_prefix = parsed_configuration.get('consistency', {}).get('prefix')
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if archive_name_format and not consistency_prefix:
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logger.warning(
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'Since version 1.1.16, if you provide `archive_name_format`, you should also'
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' specify `consistency.prefix`.'
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)
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def parse_configuration(config_filename, schema_filename):
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'''
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Given the path to a config filename in YAML format and the path to a schema filename in
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pykwalify YAML schema format, return the parsed configuration as a data structure of nested
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dicts and lists corresponding to the schema. Example return value:
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{'location': {'source_directories': ['/home', '/etc'], 'repository': 'hostname.borg'},
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'retention': {'keep_daily': 7}, 'consistency': {'checks': ['repository', 'archives']}}
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Raise FileNotFoundError if the file does not exist, PermissionError if the user does not
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have permissions to read the file, or Validation_error if the config does not match the schema.
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'''
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logging.getLogger('pykwalify').setLevel(logging.ERROR)
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try:
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config = yaml.safe_load(open(config_filename))
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schema = yaml.safe_load(open(schema_filename))
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except yaml.error.YAMLError as error:
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raise Validation_error(config_filename, (str(error),))
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# pykwalify gets angry if the example field is not a string. So rather than bend to its will,
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# simply remove all examples before passing the schema to pykwalify.
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for section_name, section_schema in schema['map'].items():
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for field_name, field_schema in section_schema['map'].items():
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field_schema.pop('example', None)
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validator = pykwalify.core.Core(source_data=config, schema_data=schema)
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parsed_result = validator.validate(raise_exception=False)
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if validator.validation_errors:
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raise Validation_error(config_filename, validator.validation_errors)
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apply_logical_validation(config_filename, parsed_result)
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return parsed_result
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