Tool to import, verify, and generate config files {json and yaml} for python.

configr.py

# -*- coding: utf-8 -*-
#!/usr/bin/env python3
#!/usr/bin/env python


"""
Configuration file manager for yaml and json.
Tool to import, verify, and generate config files {json and yaml} for python.

Author : *Yatharth Bhasin* (Github → yatharthb97)
License: *MIT open-source license* (https://opensource.org/licenses/mit-license.php)

This piece of software was released on GistHub : TODO. 
Please give credit whenever possible.
"""


import os
import json
import yaml

class Configr:
	"""
	Tools to import, verify, and generate config files for python.
	"""

	def __init__(self, filename=None, ext=".json", ref=None):
		
		# Configuration
		self.config = None

		# Declare defaults
		self.default_ext = ext
		self.default_config_name = f"autogenerated_config{self.default_ext}" #Default configuration option
		
		self.ref_config = None  # Reference config object.
		self.ref_set = False # Reference config is set flag.


		# Filename
		self.file_path = None
		if filename != None:
			self.file_path = filename

		# Reference Configuration
		if ref != None:
			self.set_ref(ref)




	def find_config(self, dir_path=".", ext="", file_key="config", alphabatical=True):
		"""
		Checks for configuration files within the current working 
		directory, does a simple search with the given `file_key`.
		
		dir_path : The directory path for search - converts to absolute file path.
		ext : Extension of file to be searched.
		file_key : [optional] key word that indicates a config file.

		args:
		---
		"alphabatical" : sorts and returns the first file in case multiple files are detected.
		"""

		# Extract all files within the folder
		file_list = [file for file in os.listdir(os.path.abspath(dir_path))]
		if ext != "":
			file_list = [file for file in file_list if ext in file]
		file_list = [file for file in file_list if file_key in file]

		
		if "alphabatical":
			file_list = sorted(file_list)
			if not file_list:
				return None
			else:
				return file_list[0]

		if len(file_list) > 1:
			print(f"[ERROR] Multiple config files options found - {file_list}.")
			return None

		elif len(file_list) == 0:
			print(f"[ERROR] No config files found!")
			return None

		else:
			return file_list[0]


	def load(self, config_file):
		"""
		Loads the file into `self.config` field as dictionary.
		Parses both json and yaml.
		"""
		if not os.path.exists(config_file):
			raise Exception(f"File does not exist: {config_file}")
		
		if config_file.endswith("yml") or config_file.endswith("yaml") or config_file.endswith("json"):
			self.file_path = config_file
			with open(config_file, 'r') as file:
				self.config = yaml.safe_load(file)
		else:
			raise Exception(f"Can only load json and yaml files.")
		return self.config


	def set_ref(self, config_dict):
		"""
		Sets the default configuration.
		"""
		self.ref_config = config_dict
		self.ref_set = True


	def export(self, filename, config_dict):
		"""
		Exports a given 
		Returns path of exported file.
		"""

		# file_type selection
		if filename.endswith(".yaml") or filename.endswith(".yml"):
			file_type = ".yaml"
		elif filename.endswith(".json"):
			file_type = ".json"
		else:
			filename += self.default_ext
			file_type = self.default_ext

		serializer = None
		if file_type == ".json":
			import json as serializer
		elif file_type == ".yaml" or file_type == ".yml":
			import yaml as serializer
		export_config = serializer.dumps(config_dict, indent=4)
		
		with open(filename, 'w') as file:
			file.write(export_config)
		
		return filename

	def export_def_config(self, filename=None):
		"""
		Generates a configuration file with default configuration options.
		Returns path of exported file.
		"""

		# Filename selection
		if filename == None:
			filename = os.path.abspath(self.default_config_name)

		self.export(filename, config_dict=self.ref_config)
		print(f"[Configr] Configuration file generated → `{filename}`.")

		return filename


	def verify_syntax(self, filename):
		"""
		Verifies synatax and catches any exceptions during the parsing of files.
		"""
		with open(filename, 'r') as file_obj:

			if filename.endswith(".json"):
				try:
					json.load(file_obj)
				except ValueError as e:
					return False
				return True
			
			if filename.endswith(".yml") or filename.endswith(".yaml"):
				try:
				    yaml.safe_load(file_obj)
				except yaml.YAMLError as e:
					return False
				return True
			else:
				return False



	def verify_and_patch(self, patch_file=True):
		"""
		Fill missing fields and generate.
		patch_file : True value applies the patch to the file as well.
		Returns `True` when verification passed without any patching, `False` otherwise.
		"""

		# Check if the default configuration is set.
		if not self.ref_set:
			raise Exception("[Configr] Default configuration is not set. Verification not possible.")

		update_state = False
		
		# Unknown keys -> Only generates warning, does not remove the extra fields.
		for key in self.config:
			if not key in self.ref_config.keys():
				print(f"[Warning] Unrecognised configuration field -> {key} : {str(self.config[key])}")

		# Missing keys
		for key in self.ref_config:
			if not key in self.config:
				self.config[key] = self.ref_config[key] #Add
				print(f"[Warning] Configuration : Missing field added -> `{key}: {str(self.config[key])}` .")
				update_state = True


		if update_state == True and patch_file == True:
			self.export(self.file_path, self.config)
		
		return (not update_state)




# Higher level APIs ↓
	def load_seq(self, directory): #TODO
		"""
		All configuration operations clubbed into one function.
		* In case multiple config possibilities exist, choose alphabetically.
		* Generate json file if config not found.
		* Patches applied to file as well.

		Returns the config dictionary at the end.
		"""
		conf_path = self.find_config(directory, ext=self.default_ext, alphabatical=True)
		if conf_path == None:
			print("[ERROR] No configuration file was found in the current directory.")
			conf_path = self.export_def_config() #To file
		
		# Load, verify and patch
		conf_path = os.path.abspath(conf_path)
		self.load(conf_path)
		self.verify_and_patch(patch_file=True)

		return self.config

#-- END of file