Source code for redbot.core.drivers.json

import asyncio
import json
import logging
import os
import pickle
import weakref
from pathlib import Path
from typing import Any, AsyncIterator, Dict, Optional, Tuple
from uuid import uuid4

from .. import data_manager, errors
from .base import BaseDriver, IdentifierData, ConfigCategory

__all__ = ["JsonDriver"]


_shared_datastore = {}
_driver_counts = {}
_finalizers = []

log = logging.getLogger("redbot.json_driver")


def finalize_driver(cog_name):
    if cog_name not in _driver_counts:
        return

    _driver_counts[cog_name] -= 1

    if _driver_counts[cog_name] == 0:
        if cog_name in _shared_datastore:
            del _shared_datastore[cog_name]

    for f in _finalizers:
        if not f.alive:
            _finalizers.remove(f)


# noinspection PyProtectedMember
[docs]class JsonDriver(BaseDriver): """ Subclass of :py:class:`.BaseDriver`. .. py:attribute:: file_name The name of the file in which to store JSON data. .. py:attribute:: data_path The path in which to store the file indicated by :py:attr:`file_name`. """ def __init__( self, cog_name: str, identifier: str, *, data_path_override: Optional[Path] = None, file_name_override: str = "settings.json", ): super().__init__(cog_name, identifier) self.file_name = file_name_override if data_path_override is not None: self.data_path = data_path_override elif cog_name == "Core" and identifier == "0": self.data_path = data_manager.core_data_path() else: self.data_path = data_manager.cog_data_path(raw_name=cog_name) self.data_path.mkdir(parents=True, exist_ok=True) self.data_path = self.data_path / self.file_name self._lock = asyncio.Lock() self._load_data() @property def data(self): return _shared_datastore.get(self.cog_name) @data.setter def data(self, value): _shared_datastore[self.cog_name] = value
[docs] @classmethod async def initialize(cls, **storage_details) -> None: # No initializing to do return
[docs] @classmethod async def teardown(cls) -> None: # No tearing down to do return
[docs] @staticmethod def get_config_details() -> Dict[str, Any]: # No driver-specific configuration needed return {}
def _load_data(self): if self.cog_name not in _driver_counts: _driver_counts[self.cog_name] = 0 _driver_counts[self.cog_name] += 1 _finalizers.append(weakref.finalize(self, finalize_driver, self.cog_name)) if self.data is not None: return try: with self.data_path.open("r", encoding="utf-8") as fs: self.data = json.load(fs) except FileNotFoundError: self.data = {} with self.data_path.open("w", encoding="utf-8") as fs: json.dump(self.data, fs) def migrate_identifier(self, raw_identifier: int): if self.unique_cog_identifier in self.data: # Data has already been migrated return poss_identifiers = [str(raw_identifier), str(hash(raw_identifier))] for ident in poss_identifiers: if ident in self.data: self.data[self.unique_cog_identifier] = self.data[ident] del self.data[ident] _save_json(self.data_path, self.data) break
[docs] async def get(self, identifier_data: IdentifierData): partial = self.data full_identifiers = identifier_data.to_tuple()[1:] for i in full_identifiers: partial = partial[i] return pickle.loads(pickle.dumps(partial, -1))
[docs] async def set(self, identifier_data: IdentifierData, value=None): partial = self.data full_identifiers = identifier_data.to_tuple()[1:] # This is both our deepcopy() and our way of making sure this value is actually JSON # serializable. value_copy = json.loads(json.dumps(value)) async with self._lock: for i in full_identifiers[:-1]: try: partial = partial.setdefault(i, {}) except AttributeError: # Tried to set sub-field of non-object raise errors.CannotSetSubfield partial[full_identifiers[-1]] = value_copy await self._save()
[docs] async def clear(self, identifier_data: IdentifierData): partial = self.data full_identifiers = identifier_data.to_tuple()[1:] try: for i in full_identifiers[:-1]: partial = partial[i] except KeyError: pass else: async with self._lock: try: del partial[full_identifiers[-1]] except KeyError: pass else: await self._save()
[docs] @classmethod async def aiter_cogs(cls) -> AsyncIterator[Tuple[str, str]]: yield "Core", "0" for _dir in data_manager.cog_data_path().iterdir(): fpath = _dir / "settings.json" if not fpath.exists(): continue with fpath.open() as f: try: data = json.load(f) except json.JSONDecodeError: continue if not isinstance(data, dict): continue for cog, inner in data.items(): if not isinstance(inner, dict): continue for cog_id in inner: yield cog, cog_id
async def import_data(self, cog_data, custom_group_data): def update_write_data(identifier_data: IdentifierData, _data): partial = self.data idents = identifier_data.to_tuple()[1:] for ident in idents[:-1]: partial = partial.setdefault(ident, {}) partial[idents[-1]] = _data async with self._lock: for category, all_data in cog_data: splitted_pkey = self._split_primary_key(category, custom_group_data, all_data) for pkey, data in splitted_pkey: ident_data = IdentifierData( self.cog_name, self.unique_cog_identifier, category, pkey, (), *ConfigCategory.get_pkey_info(category, custom_group_data), ) update_write_data(ident_data, data) await self._save() async def _save(self) -> None: loop = asyncio.get_running_loop() await loop.run_in_executor(None, _save_json, self.data_path, self.data)
def _save_json(path: Path, data: Dict[str, Any]) -> None: """ This fsync stuff here is entirely neccessary. On windows, it is not available in entirety. If a windows user ends up with tons of temp files, they should consider hosting on something POSIX compatible, or using the mongo backend instead. Most users wont encounter this issue, but with high write volumes, without the fsync on both the temp file, and after the replace on the directory, There's no real durability or atomicity guarantee from the filesystem. In depth overview of underlying reasons why this is needed: https://lwn.net/Articles/457667/ Also see: http://man7.org/linux/man-pages/man2/open.2.html#NOTES (synchronous I/O section) And: https://www.mjmwired.net/kernel/Documentation/filesystems/ext4.txt#310 """ filename = path.stem tmp_file = "{}-{}.tmp".format(filename, uuid4().fields[0]) tmp_path = path.parent / tmp_file with tmp_path.open(encoding="utf-8", mode="w") as fs: json.dump(data, fs) fs.flush() # This does get closed on context exit, ... os.fsync(fs.fileno()) # but that needs to happen prior to this line tmp_path.replace(path) try: flag = os.O_DIRECTORY # pylint: disable=no-member except AttributeError: pass else: fd = os.open(path.parent, flag) try: os.fsync(fd) finally: os.close(fd)