pferd/PFERD/config.py

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2021-04-27 12:41:49 +02:00
import configparser
import os
from pathlib import Path
from typing import Optional
from .utils import prompt_yes_no
class ConfigLoadException(Exception):
pass
class ConfigDumpException(Exception):
pass
class Config:
@staticmethod
def _default_path() -> Path:
if os.name == "posix":
return Path("~/.config/PFERD/pferd.cfg").expanduser()
elif os.name == "nt":
return Path("~/AppData/Roaming/PFERD/pferd.cfg").expanduser()
else:
return Path("~/.pferd.cfg").expanduser()
def __init__(self, parser: configparser.ConfigParser):
self._parser = parser
# TODO Load and validate config into dataclasses
@staticmethod
def _fail_load(path: Path, reason: str) -> None:
print(f"Failed to load config file at {path}")
print(f"Reason: {reason}")
raise ConfigLoadException()
@staticmethod
def load_parser(path: Optional[Path] = None) -> configparser.ConfigParser:
"""
May throw a ConfigLoadException.
"""
if not path:
path = Config._default_path()
parser = configparser.ConfigParser()
# Using config.read_file instead of config.read because config.read
# would just ignore a missing file and carry on.
try:
with open(path) as f:
parser.read_file(f, source=str(path))
except FileNotFoundError:
Config._fail_load(path, "File does not exist")
except IsADirectoryError:
Config._fail_load(path, "That's a directory, not a file")
except PermissionError:
Config._fail_load(path, "Insufficient permissions")
return parser
@staticmethod
def _fail_dump(path: Path, reason: str) -> None:
print(f"Failed to dump config file to {path}")
print(f"Reason: {reason}")
raise ConfigDumpException()
def dump(self, path: Optional[Path] = None) -> None:
"""
May throw a ConfigDumpException.
"""
if not path:
path = self._default_path()
print(f"Dumping config to {path}")
try:
path.parent.mkdir(parents=True, exist_ok=True)
except PermissionError:
self._fail_dump(path, "Could not create parent directory")
try:
# Ensuring we don't accidentally overwrite any existing files by
# always asking before overwriting a file.
try:
# x = open for exclusive creation, failing if the file already
# exists
with open(path, "x") as f:
self._parser.write(f)
except FileExistsError:
print("That file already exists.")
if prompt_yes_no("Overwrite it?", default=False):
with open(path, "w") as f:
self._parser.write(f)
else:
self._fail_dump(path, "File already exists")
except IsADirectoryError:
self._fail_dump(path, "That's a directory, not a file")
except PermissionError:
self._fail_dump(path, "Insufficient permissions")