Refactor configuration to use a file exclusively

inquisitor/configs.py

@@ -1,24 +0,0 @@
-import os
-import logging
-
-DUNGEON_PATH = os.path.abspath(os.environ.get("INQUISITOR_DUNGEON") or "./dungeon")
-SOURCES_PATH = os.path.abspath(os.environ.get("INQUISITOR_SOURCES") or "./sources")
-CACHE_PATH = os.path.abspath(os.environ.get("INQUISITOR_CACHE") or "./cache")
-
-logger = logging.getLogger("inquisitor")
-handler = logging.StreamHandler()
-logger.addHandler(handler)
-
-def log_normal():
-	logger.setLevel(logging.INFO)
-	handler.setLevel(logging.INFO)
-	formatter = logging.Formatter('[{levelname}] {message}', style="{")
-	handler.setFormatter(formatter)
-
-def log_verbose():
-	logger.setLevel(logging.DEBUG)
-	handler.setLevel(logging.DEBUG)
-	formatter = logging.Formatter('[{asctime}] [{levelname}:{filename}:{lineno}] {message}', style="{")
-	handler.setFormatter(formatter)
-
-log_normal()

inquisitor/configs/__init__.py

@@ -0,0 +1,4 @@
+from .resolver import data_path as DUNGEON_PATH
+from .resolver import source_path as SOURCES_PATH
+from .resolver import cache_path as CACHE_PATH
+from .resolver import logger, add_logging_handler, init_default_logging

inquisitor/configs/resolver.py

@@ -0,0 +1,125 @@
+import os
+import logging
+
+
+# Constants governing config resolution:
+# Path to the config file, containing key-value pairs of the other settings
+CONFIG_ENVVAR = 'INQUISITOR_CONFIG'
+DEFAULT_CONFIG_PATH = '/etc/inquisitor.conf'
+
+# Path to the folder where items are stored
+CONFIG_DATA = 'DataPath'
+DEFAULT_DATA_PATH = '/var/inquisitor/data/'
+
+# Path to the folder where source modules are stored
+CONFIG_SOURCES = 'SourcePath'
+DEFAULT_SOURCES_PATH = '/var/inquisitor/sources/'
+
+# Path to the folder where cached files are stored
+CONFIG_CACHE = 'CachePath'
+DEFAULT_CACHE_PATH = '/var/inquisitor/cache/'
+
+# Path to a log file where logging will be redirected
+CONFIG_LOGFILE = 'LogFile'
+DEFAULT_LOG_FILE = None
+
+# Whether logging is verbose
+CONFIG_VERBOSE = 'Verbose'
+DEFAULT_VERBOSITY = False
+
+
+def read_config_file(config_path):
+	"""
+	Reads a config file of key-value pairs, where non-blank lines are
+	either comments beginning with the character '#' or keys and values
+	separated by the character '='.
+	"""
+	# Parse the config file into key-value pairs
+	if not os.path.isfile(config_path):
+		raise FileNotFoundError(f'No config file found at {config_path}')
+	accumulated_configs = {}
+	with open(config_path, 'r', encoding='utf8') as cfg:
+		line_no = 0
+		for line in cfg:
+			line_no += 1
+			# Skip blank lines
+			if not line.strip():
+				continue
+			# Skip comments
+			if line.lstrip().startswith('#'):
+				continue
+			# Accumulate config keyvalue pairs
+			if '=' not in line:
+				raise ValueError(f'Invalid config format on line {line_no}')
+			key, value = line.split('=', maxsplit=1)
+			accumulated_configs[key.strip()] = value.strip()
+
+	return accumulated_configs
+
+
+# Read envvar for config file location, with fallback to default
+config_path = os.path.abspath(
+	os.environ.get(CONFIG_ENVVAR) or
+	DEFAULT_CONFIG_PATH
+)
+
+configs = read_config_file(config_path)
+
+# Extract and validate config values
+data_path = configs.get(CONFIG_DATA) or DEFAULT_DATA_PATH
+if not os.path.isabs(data_path):
+	raise ValueError(f'Non-absolute data path: {data_path}')
+if not os.path.isdir(data_path):
+	raise FileNotFoundError(f'Cannot find directory {data_path}')
+
+source_path = configs.get(CONFIG_SOURCES) or DEFAULT_SOURCES_PATH
+if not os.path.isabs(source_path):
+	raise ValueError(f'Non-absolute source path: {source_path}')
+if not os.path.isdir(source_path):
+	raise FileNotFoundError(f'Cannot find directory {source_path}')
+
+cache_path = configs.get(CONFIG_CACHE) or DEFAULT_CACHE_PATH
+if not os.path.isabs(cache_path):
+	raise ValueError(f'Non-absolute cache path: {cache_path}')
+if not os.path.isdir(cache_path):
+	raise FileNotFoundError(f'Cannot find directory {cache_path}')
+
+log_file = configs.get(CONFIG_LOGFILE) or DEFAULT_LOG_FILE
+if log_file and not os.path.isabs(log_file):
+	raise ValueError(f'Non-absolute log file path: {log_file}')
+
+is_verbose = (configs.get(CONFIG_VERBOSE) == 'true') or DEFAULT_VERBOSITY
+
+
+# Set up logging
+logger = logging.getLogger("inquisitor")
+logger.setLevel(logging.DEBUG)
+
+def add_logging_handler(verbose, log_filename):
+	"""
+	Adds a logging handler according to the given settings
+	"""
+	log_format = (
+		'[{asctime}] [{levelname}:{filename}:{lineno}] {message}'
+		if verbose else
+		'[{levelname}] {message}'
+	)
+	formatter = logging.Formatter(log_format, style='{')
+
+	log_level = (
+		logging.DEBUG
+		if verbose else
+		logging.INFO
+	)
+	handler = (
+		logging.FileHandler(log_filename, encoding='utf8')
+		if log_filename else
+		logging.StreamHandler()
+	)
+	handler.setFormatter(formatter)
+	handler.setLevel(log_level)
+
+	logger.addHandler(handler)
+
+def init_default_logging():
+	add_logging_handler(is_verbose, log_file)