Source code for cowbird.constants

#!/usr/bin/env python
# -*- coding: utf-8 -*-
Constant settings for Cowbird application.

Constants defined with format ``COWBIRD_[VARIABLE_NAME]`` can be matched with corresponding
settings formatted as ``cowbird.[variable_name]`` in the ``cowbird.ini`` configuration file.

.. note::
    Since the ``cowbird.ini`` file has to be loaded by the application to retrieve various configuration settings,
    constant ``COWBIRD_INI_FILE_PATH`` (or any other `path variable` defined before it - see below) has to be defined
    by environment variable if the default location is not desired (ie: if you want to provide your own configuration).
import logging
import os
import re
from typing import Optional, cast
from typing_extensions import Literal

from pyramid.settings import asbool
from pyramid.threadlocal import get_current_registry

from cowbird.typedefs import AnySettingsContainer, SettingValue

[docs]AnyLogLevel = Literal[ "NOTSET", 0, "DEBUG", "debug", 10, "INFO", "info", 20, "WARNING", "warning", 30, "ERROR", "error", 40, "FATAL", "fatal", 50, "CRITICAL", "critical", 50, ]
# =========================== # path variables # ===========================
[docs]COWBIRD_MODULE_DIR = os.path.abspath(os.path.dirname(__file__))
[docs]COWBIRD_ROOT = os.path.dirname(COWBIRD_MODULE_DIR)
[docs]COWBIRD_CONFIG_DIR = os.getenv( "COWBIRD_CONFIG_DIR", os.path.join(COWBIRD_ROOT, "config"))
[docs]COWBIRD_CONFIG_PATH = os.getenv("COWBIRD_CONFIG_PATH") # default None, require explicit specification
# UID/GID used in birdhouse. We should assign the user's resources to this owner, so that the resources can be # accessible to the user via JupyterHub.
[docs]DEFAULT_USER_UID = int(os.getenv("COWBIRD_FILESYSTEM_USER_UID", 1000))
[docs]DEFAULT_USER_GID = int(os.getenv("COWBIRD_FILESYSTEM_USER_GID", 1000))
[docs]def _get_default_log_level() -> AnyLogLevel: """ Get logging level from INI configuration file or fallback to default ``INFO`` if it cannot be retrieved. """ _default_log_lvl = "INFO" try: from cowbird.utils import get_settings_from_config_ini # pylint: disable=C0415 # avoid circular import error _settings = get_settings_from_config_ini(COWBIRD_INI_FILE_PATH, section="logger_cowbird") _default_log_lvl = _settings.get("level", _default_log_lvl) # also considers 'ModuleNotFoundError' derived from 'ImportError', but not added to avoid Python <3.6 name error except (AttributeError, ImportError): # noqa: W0703 # nosec: B110 pass return cast(AnyLogLevel, _default_log_lvl)
# =========================== # variables from cowbird.env # =========================== # --------------------------- # COWBIRD # ---------------------------
[docs]COWBIRD_URL = os.getenv("COWBIRD_URL", None) # must be defined
[docs]COWBIRD_LOG_LEVEL = os.getenv("COWBIRD_LOG_LEVEL", _get_default_log_level()) # log level to apply to the loggers
[docs]COWBIRD_LOG_PRINT = asbool(os.getenv("COWBIRD_LOG_PRINT", False)) # log also forces print to the console
[docs]COWBIRD_LOG_REQUEST = asbool(os.getenv("COWBIRD_LOG_REQUEST", True)) # log detail of every incoming request
[docs]COWBIRD_LOG_EXCEPTION = asbool(os.getenv("COWBIRD_LOG_EXCEPTION", True)) # log detail of generated exceptions
# =========================== # constants # =========================== # ignore matches of settings and environment variables for following cases
# =========================== # utilities # ===========================
[docs]_REGEX_ASCII_ONLY = re.compile(r"\W|^(?=\d)")
[docs]_SETTING_SECTION_PREFIXES = [ "cowbird", ]
[docs]_SETTINGS_REQUIRED = [ "COWBIRD_URL", "COWBIRD_CONFIG_PATH", # FIXME: add others here as needed ]
[docs]def get_constant_setting_name(name: str) -> str: """ Find the equivalent setting name of the provided environment variable name. Lower-case name and replace all non-ascii chars by `_`. Then, convert known prefixes with their dotted name. """ name = re.sub(_REGEX_ASCII_ONLY, "_", name.strip().lower()) for prefix in _SETTING_SECTION_PREFIXES: known_prefix = f"{prefix}_" dotted_prefix = f"{prefix}." if name.startswith(known_prefix): return name.replace(known_prefix, dotted_prefix, 1) return name
[docs]def get_constant(constant_name: str, settings_container: Optional[AnySettingsContainer] = None, settings_name: Optional[str] = None, default_value: Optional[SettingValue] = None, raise_missing: bool = True, print_missing: bool = False, raise_not_set: bool = True ) -> SettingValue: """ Search in order for matched value of :paramref:`constant_name`: 1. search in :py:data:`COWBIRD_CONSTANTS` 2. search in settings if specified 3. search alternative setting names (see below) 4. search in :mod:`cowbird.constants` definitions 5. search in environment variables Parameter :paramref:`constant_name` is expected to have the format ``COWBIRD_[VARIABLE_NAME]`` although any value can be passed to retrieve generic settings from all above-mentioned search locations. If :paramref:`settings_name` is provided as alternative name, it is used as is to search for results if :paramref:`constant_name` was not found. Otherwise, ``cowbird.[variable_name]`` is used for additional search when the format ``COWBIRD_[VARIABLE_NAME]`` was used for :paramref:`constant_name` (i.e.: ``COWBIRD_ADMIN_USER`` will also search for ``cowbird.admin_user`` and so on for corresponding constants). :param constant_name: key to search for a value :param settings_container: WSGI application settings container (if not provided, uses found one in current thread) :param settings_name: alternative name for `settings` if specified :param default_value: default value to be returned if not found anywhere, and exception raises are disabled. :param raise_missing: raise exception if key is not found anywhere :param print_missing: print message if key is not found anywhere, return ``None`` :param raise_not_set: raise an exception if the found key is ``None``, search until last case if others are ``None`` :returns: found value or `default_value` :raises ValueError: if resulting value is invalid based on options (by default raise missing/``None`` value) :raises LookupError: if no appropriate value could be found from all search locations (according to options) """ from cowbird.utils import get_settings, print_log, raise_log # pylint: disable=C0415 # avoid circular import error if constant_name in COWBIRD_CONSTANTS: return globals()[constant_name] missing = True cowbird_value = None if settings_container: settings = get_settings(settings_container) else: # note: this will work only after include of cowbird will have triggered configurator setup print_log("Using settings from local thread.", level=logging.DEBUG) settings = get_settings(get_current_registry()) if settings and constant_name in settings: # pylint: disable=E1135 missing = False cowbird_value = settings.get(constant_name) if cowbird_value is not None: print_log(f"Constant found in settings with: {constant_name}", level=logging.DEBUG) return cowbird_value if not settings_name: settings_name = get_constant_setting_name(constant_name) print_log(f"Constant alternate search: {settings_name}", level=logging.DEBUG) if settings and settings_name and settings_name in settings: # pylint: disable=E1135 missing = False cowbird_value = settings.get(settings_name) if cowbird_value is not None: print_log(f"Constant found in settings with: {settings_name}", level=logging.DEBUG) return cowbird_value cowbird_globals = globals() if constant_name in cowbird_globals: missing = False cowbird_value = cowbird_globals.get(constant_name) if cowbird_value is not None: print_log(f"Constant found in definitions with: {constant_name}", level=logging.DEBUG) return cowbird_value if constant_name in os.environ: missing = False cowbird_value = os.environ.get(constant_name) if cowbird_value is not None: print_log(f"Constant found in environment with: {constant_name}", level=logging.DEBUG) return cowbird_value if not missing and raise_not_set: raise_log(f"Constant was found but was not set: {constant_name}", level=logging.ERROR, exception=ValueError) if missing and raise_missing: raise_log(f"Constant could not be found: {constant_name}", level=logging.ERROR, exception=LookupError) if missing and print_missing: print_log(f"Constant could not be found: {constant_name} (using default: {default_value})", level=logging.WARN) return cowbird_value or default_value
[docs]def validate_required(container: AnySettingsContainer) -> None: """ Validates that some value is provided for every mandatory configuration setting. :raises: when any of the requirements are missing a definition. """ for cfg in _SETTINGS_REQUIRED: get_constant(cfg, settings_container=container, raise_missing=True, raise_not_set=True)