153 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			153 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
"""passbook core config loader"""
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import os
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from collections.abc import Mapping
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from contextlib import contextmanager
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from glob import glob
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from typing import Any
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from urllib.parse import urlparse
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import yaml
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from django.conf import ImproperlyConfigured
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from django.utils.autoreload import autoreload_started
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from structlog import get_logger
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SEARCH_PATHS = [
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    'passbook/lib/default.yml',
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    '/etc/passbook/config.yml',
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    '',
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] + glob('/etc/passbook/config.d/*.yml', recursive=True)
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LOGGER = get_logger()
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ENV_PREFIX = 'PASSBOOK'
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ENVIRONMENT = os.getenv(f'{ENV_PREFIX}_ENV', 'local')
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class ConfigLoader:
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    """Search through SEARCH_PATHS and load configuration. Environment variables starting with
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    `ENV_PREFIX` are also applied.
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    A variable like PASSBOOK_POSTGRESQL__HOST would translate to postgresql.host"""
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    loaded_file = []
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    __config = {}
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    __sub_dicts = []
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    def __init__(self):
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        super().__init__()
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        base_dir = os.path.realpath(os.path.join(os.path.dirname(__file__), '../..'))
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        for path in SEARCH_PATHS:
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            # Check if path is relative, and if so join with base_dir
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            if not os.path.isabs(path):
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                path = os.path.join(base_dir, path)
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            if os.path.isfile(path) and os.path.exists(path):
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                # Path is an existing file, so we just read it and update our config with it
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                self.update_from_file(path)
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            elif os.path.isdir(path) and os.path.exists(path):
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                # Path is an existing dir, so we try to read the env config from it
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                env_paths = [os.path.join(path, ENVIRONMENT + '.yml'),
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                             os.path.join(path, ENVIRONMENT + '.env.yml')]
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                for env_file in env_paths:
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                    if os.path.isfile(env_file) and os.path.exists(env_file):
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                        # Update config with env file
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                        self.update_from_file(env_file)
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        self.update_from_env()
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    def update(self, root, updatee):
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        """Recursively update dictionary"""
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        for key, value in updatee.items():
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            if isinstance(value, Mapping):
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                root[key] = self.update(root.get(key, {}), value)
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            else:
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                if isinstance(value, str):
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                    value = self.parse_uri(value)
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                root[key] = value
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        return root
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    def parse_uri(self, value):
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        """Parse string values which start with a URI"""
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        url = urlparse(value)
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        if url.scheme == 'env':
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            value = os.getenv(url.netloc, url.query)
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        return value
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    def update_from_file(self, path: str):
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        """Update config from file contents"""
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        try:
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            with open(path) as file:
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                try:
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                    self.update(self.__config, yaml.safe_load(file))
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                    LOGGER.debug("Loaded config", file=path)
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                    self.loaded_file.append(path)
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                except yaml.YAMLError as exc:
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                    raise ImproperlyConfigured from exc
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        except PermissionError as exc:
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            LOGGER.warning('Permission denied while reading %s', path)
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    def update_from_dict(self, update: dict):
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        """Update config from dict"""
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        self.__config.update(update)
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    def update_from_env(self):
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        """Check environment variables"""
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        outer = {}
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        idx = 0
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        for key, value in os.environ.items():
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            if not key.startswith(ENV_PREFIX):
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                continue
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            relative_key = key.replace(f"{ENV_PREFIX}_", '').replace('__', '.').lower()
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            # Recursively convert path from a.b.c into outer[a][b][c]
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            current_obj = outer
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            dot_parts = relative_key.split('.')
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            for dot_part in dot_parts[:-1]:
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                if dot_part not in current_obj:
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                    current_obj[dot_part] = {}
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                current_obj = current_obj[dot_part]
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            current_obj[dot_parts[-1]] = value
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            idx += 1
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        if idx > 0:
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            LOGGER.debug("Loaded environment variables", count=idx)
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            self.update(self.__config, outer)
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    @contextmanager
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    # pylint: disable=invalid-name
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    def cd(self, sub: str):
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        """Contextmanager that descends into sub-dict. Can be chained."""
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        self.__sub_dicts.append(sub)
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        yield
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        self.__sub_dicts.pop()
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    @property
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    def raw(self) -> dict:
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        """Get raw config dictionary"""
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        return self.__config
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    # pylint: disable=invalid-name
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    def y(self, path: str, default=None, sep='.') -> Any:
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        """Access attribute by using yaml path"""
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        # Walk sub_dicts before parsing path
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        root = self.raw
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        for sub in self.__sub_dicts:
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            root = root.get(sub, None)
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        # Walk each component of the path
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        for comp in path.split(sep):
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            if comp in root:
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                root = root.get(comp)
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            else:
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                return default
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        return root
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    def y_bool(self, path: str, default=False) -> bool:
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        """Wrapper for y that converts value into boolean"""
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        return str(self.y(path, default)).lower() == 'true'
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CONFIG = ConfigLoader()
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def signal_handler(sender, **_):
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    """Add all loaded config files to autoreload watcher"""
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    for path in CONFIG.loaded_file:
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        sender.watch_file(path)
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autoreload_started.connect(signal_handler)
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