138 lines
4.9 KiB
Python
138 lines
4.9 KiB
Python
import yaml
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import yaql
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from os import getenv, getcwd, putenv
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from os.path import exists,isfile,isdir
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from typing import Any
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class FileReference:
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"""
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!FileReference should simply refer to a file that exists.
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The file is not loaded as part of the configuration.
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"""
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yaml_tag = '!FileReference'
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yaml_loader = yaml.SafeLoader
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yaml_dumper = yaml.SafeDumper
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filename: str = None
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def __init__(self, filename: str):
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self.filename = filename
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@property
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def scalar_value(self):
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return self.filename
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def __repr__(self):
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fn = self.filename
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exists = isfile(fn)
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return ("(reference to '{}')" if exists else "(invalid reference to '{}')").format(fn)
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class FileData(yaml.YAMLObject):
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"""
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!FileData should refer to a file that exists.
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The file's contents are then loaded as a string
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and available for reference.
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"""
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yaml_tag = '!FileData'
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yaml_loader = yaml.SafeLoader
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yaml_dumper = yaml.SafeDumper
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filename: str = None
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data: Any = None
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def __init__(self, filename: str):
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self.filename = filename
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@property
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def scalar_value(self):
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return self.filename
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def read_data(self):
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if self.data is not None: return self.data
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with open(self.filename,'r') as file:
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self.data = file.read()
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return self.data
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def calculate_data_hash(self):
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# to-do: actually hash the data
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return self.data[:10] if isinstance(self.data,str) else 'DATA HASH'
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def __repr__(self):
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hashdata = self.calculate_data_hash()
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return '(filename:{filename:}, data hash: {hashdata:})'.format(filename=self.filename,hashdata=hashdata)
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class EncryptedFileData(FileData):
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yaml_tag = '!EncryptedFileData'
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yaml_loader = yaml.SafeLoader
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yaml_dumper = yaml.SafeDumper
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def __init__(self, filename: str, key: str | FileData):
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self.filename = filename
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self.key = key
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def key_data(self):
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if isinstance(self.key, str): return self.key
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if isinstance(self.key, FileData):
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return self.key.read_data()
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def decrypt(self, data, key):
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return data
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def read_data(self):
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base_data = super().read_data()
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key_data = self.key_data()
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return self.decrypt(base_data, key_data)
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def __repr__(self):
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return '(encrypted file: {:})'.format(self.filename)
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def generic_representer(dumper, data):
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return dumper.represent_scalar(type(data).yaml_tag, data.scalar_value)
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def filedata_constructor(loader, node):
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filename = loader.construct_scalar(node)
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return FileData(filename)
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def fileref_constructor(loader, node):
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filename = loader.construct_scalar(node)
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return FileReference(filename)
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yaml.add_representer(FileData, generic_representer)
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yaml.add_constructor(FileData.yaml_tag, filedata_constructor, yaml.SafeLoader)
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yaml.add_representer(FileReference, generic_representer)
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yaml.add_constructor(FileReference.yaml_tag, fileref_constructor, yaml.SafeLoader)
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class Configuration:
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appname: str = ''
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document: Any = None
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engine: Any = None
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def __init__(self):
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self.engine = yaql.factory.YaqlFactory().create()
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@property
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def specified_configfile_variable_name(self):
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return self.appname+"_CONFIG_FILE"
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def find_config_file(self) -> str:
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specified_file = getenv(self.specified_configfile_variable_name)
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if specified_file is not None:
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return specified_file
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home = getenv('HOME')
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pwd = getcwd()
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populate_template = lambda base:base.format(appname=self.appname,pwd=pwd,home=home)
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paths = map(populate_template,[
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"{pwd:}/.config.yaml",
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"{home:}/.config/{appname:}/.config.yaml",
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"/etc/{appname:}/.config.yaml"
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])
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for path in paths:
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if isfile(path):
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return path
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def specify_config_file(self, fn):
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putenv(self.specified_configfile_variable_name, fn)
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def load_data(self, config_source=None):
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if isinstance(config_source, str):
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self.document = yaml.safe_load(config_source)
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return
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filename_to_load = self.find_config_file()
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with open(filename_to_load,'r') as config_file:
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self.document = yaml.safe_load(filename_to_load)
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def save_config(self):
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filename_to_load = self.find_config_file()
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with open(filename_to_load,'w') as config_file:
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yaml.safe_dump(self.document, config_file, default_flow_style=False)
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def dump_config(self):
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return yaml.safe_dump(self.document)
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def query(self,query):
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expression = self.engine(query)
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return expression.evaluate(data=self.document)
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def query_property(query, unpack_filedata=True, null_invalid_file_references=True):
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def run_query(config):
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results = config.query(query)
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if not (unpack_filedata or null_invalid_file_references):
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return results
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return property(run_query) |