395 lines
12 KiB
Python
395 lines
12 KiB
Python
import asyncio
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import concurrent.futures
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import json
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import pathlib
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import pickle
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import threading
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import traceback
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from io import StringIO
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from typing import Any, Optional, IO, Type, Hashable
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__all__ = ('KVRequest', 'KVJson', 'DbConnection', 'DbFactory', 'Db',)
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class Request:
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def __init__(self, future: Optional[asyncio.Future]):
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self.future = future
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def set_result(self, result):
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if self.future:
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self.future.set_result(result)
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def set_exception(self, exception):
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if self.future:
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self.future.set_exception(exception)
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class KVRequest(Request):
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def __init__(self, key: Any, value: Any, future: Optional[asyncio.Future]):
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super().__init__(future)
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self.key = key
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self.value = value
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def free(self):
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return type(self)(self.key, self.value, None)
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def line(self) -> str:
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raise NotImplementedError
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@classmethod
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def fromline(cls, line: str) -> 'KVRequest':
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raise NotImplementedError
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class DumpRequest(Request):
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pass
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class UnkownRequestType(TypeError):
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pass
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class KVPickle(KVRequest):
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def line(self) -> str:
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return pickle.dumps(self.free()).hex() + "\n"
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@classmethod
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def fromline(cls, line: str) -> 'KVPickle':
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return pickle.loads(bytes.fromhex(line.strip()))
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class KVJson(KVRequest):
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def line(self) -> str:
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return json.dumps({'key': self.key, 'value': self.value}) + "\n"
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@classmethod
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def _load_key(cls, key: Any) -> Hashable:
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if isinstance(key, Hashable):
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return key
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elif isinstance(key, list):
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return tuple(map(cls._load_key, key))
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elif isinstance(key, dict):
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return tuple((cls._load_key(k), cls._load_key(v)) for k, v in key)
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else:
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raise TypeError("unknown KVJson key type, cannot convert to hashable")
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@classmethod
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def fromline(cls, line: str) -> 'KVJson':
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d = json.loads(line)
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return KVJson(cls._load_key(d['key']), d['value'], None)
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class ErrorRequest(Request):
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def __init__(self, line: str, future: Optional[asyncio.Future]):
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super().__init__(future)
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self.line = line
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async def wait(self):
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if self.future:
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await self.future
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class TransactionRequest(Request):
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def __init__(self, buffer: StringIO, future: Optional[asyncio.Future]):
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super().__init__(future)
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self.buffer = buffer
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def line(self) -> str:
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return self.buffer.getvalue()
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class DbConnection:
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__mmdb: dict
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__loop: asyncio.AbstractEventLoop
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__queue: asyncio.Queue[Request]
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__file: IO[str]
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__buffer: StringIO
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__task: asyncio.Future
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__initial_size: int
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def __init__(
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self,
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factory: 'DbFactory',
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) -> None:
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self.factory = factory
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path = self.factory.path
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self.__path = pathlib.Path(path)
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self.__path_backup = pathlib.Path(path + '.backup')
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self.__path_recover = pathlib.Path(path + '.recover')
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self.__path_error = pathlib.Path(path + '.error')
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self.not_running = True
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def _queue_error(self, line: str):
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request = ErrorRequest(line, self.__loop.create_future())
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self.__queue.put_nowait(request)
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self.__loop.create_task(request.wait())
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def io2db(self, io: IO[str], db: dict) -> int:
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size = 0
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for line in io:
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try:
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request = self.factory.kvrequest_type.fromline(line)
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db[request.key] = request.value
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size += len(line)
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except (json.JSONDecodeError, pickle.UnpicklingError, EOFError):
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traceback.print_exc()
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self._queue_error(line)
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return size
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def db2io(self, db: dict, io: IO[str]) -> int:
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size = 0
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for key, value in db.items():
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size += io.write(self.factory.kvrequest_type(key, value, None).line())
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return size
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def get(self, key: Any, default: Any):
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return self.__mmdb.get(key, default)
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async def set(self, key: Any, value: Any):
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self.__mmdb[key] = value
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future = self.__loop.create_future()
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self.__queue.put_nowait(self.factory.kvrequest_type(key, value, future))
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await future
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def set_nowait(self, key: Any, value: Any):
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self.__mmdb[key] = value
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self.__queue.put_nowait(self.factory.kvrequest_type(key, value, None))
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async def _dump_buffer_or_request_so(self, request: Request):
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if self.__buffer.tell() >= self.factory.buffersize:
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await self._dump_buffer()
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request.set_result(None)
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else:
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await self.__queue.put(DumpRequest(request.future))
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async def _write(self, line: str, request: Request):
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self.__buffer.write(line)
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await self._dump_buffer_or_request_so(request)
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def _clear_buffer(self):
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self.__buffer = StringIO()
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def _compress_buffer(self) -> StringIO:
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self.__buffer.seek(0)
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bufferdb = {}
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self.io2db(self.__buffer, bufferdb)
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buffer = StringIO()
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self.db2io(bufferdb, buffer)
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return buffer
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async def _dump_compressed_buffer(self):
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buffer = self._compress_buffer()
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await self.__loop.run_in_executor(None, self.__file.write, buffer.getvalue())
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async def _do_dump_buffer(self):
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await self._dump_compressed_buffer()
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self._clear_buffer()
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async def _reload_if_oversized(self):
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if self.__file.tell() > 2 * self.__initial_size:
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await self._reload()
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async def _dump_buffer(self):
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if self.__buffer.tell():
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await self._do_dump_buffer()
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await self._reload_if_oversized()
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async def _save_error(self, line: str):
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with open(self.__path_error, 'a') as file:
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await self.__loop.run_in_executor(None, file.write, line.strip() + '\n')
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async def _handle_request(self, request: Request):
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if isinstance(request, self.factory.kvrequest_type):
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await self._write(request.line(), request)
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elif isinstance(request, DumpRequest):
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await self._dump_buffer()
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request.set_result(None)
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elif isinstance(request, ErrorRequest):
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await self._save_error(request.line)
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elif isinstance(request, TransactionRequest):
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await self._write(request.line(), request)
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else:
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raise UnkownRequestType
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async def _background_cycle(self):
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request: Request = await self.__queue.get()
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try:
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await self._handle_request(request)
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except Exception as e:
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request.set_exception(e)
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finally:
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self.__queue.task_done()
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async def _background_task(self):
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while True:
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await self._background_cycle()
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def _copy_sync(self):
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db = {}
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with open(self.__path_backup) as file:
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self.io2db(file, db)
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with open(self.__path, 'w') as file:
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self.db2io(db, file)
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def _finish_recovery_sync(self):
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self._copy_sync()
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self.__path_recover.unlink()
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self.__path_backup.unlink()
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def _build_file_sync(self, db: dict):
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with open(self.__path_backup, "w") as file:
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self.__initial_size = self.db2io(db, file)
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self.__path_recover.touch()
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self._finish_recovery_sync()
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def _run_in_thread(self, fn, *args, **kwargs) -> asyncio.Future:
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future = self.__loop.create_future()
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def wrap():
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try:
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result = fn(*args, **kwargs)
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except Exception as exception:
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self.__loop.call_soon_threadsafe(future.set_exception, exception)
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else:
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self.__loop.call_soon_threadsafe(future.set_result, result)
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threading.Thread(target=wrap).start()
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return future
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async def _build_file(self, db: dict):
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await self._run_in_thread(self._build_file_sync, db)
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def _rebuild_file_sync(self, db: dict):
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if self.__path_recover.exists():
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self._finish_recovery_sync()
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self.__path.touch()
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with open(self.__path) as file:
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self.io2db(file, db)
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self._build_file_sync(db)
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async def _rebuild_file(self, db: dict):
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await self._run_in_thread(self._rebuild_file_sync, db)
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async def _reload(self):
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self.__file.close()
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await self._rebuild_file({})
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self.__file = open(self.__path, "a")
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async def _load_from_file(self):
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await self._rebuild_file(self.__mmdb)
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async def _initialize_mmdb(self):
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self.__mmdb = {}
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await self._load_from_file()
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self.__file = open(self.__path, "a")
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async def _initialize_queue(self):
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self.__queue = asyncio.Queue()
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self.__buffer = StringIO()
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async def _start_task(self):
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self.__task = self.__loop.create_task(self._background_task())
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async def _initialize(self):
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assert self.not_running
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self.__loop = asyncio.get_event_loop()
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await self._initialize_queue()
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await self._initialize_mmdb()
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await self._start_task()
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self.not_running = False
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@classmethod
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async def create(cls, factory: 'DbFactory') -> 'DbConnection':
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dbconnection = DbConnection(factory)
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await dbconnection._initialize()
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return dbconnection
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async def aclose(self):
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if not self.__task.done():
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await self.__queue.join()
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self.__task.cancel()
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await self._dump_buffer()
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self.__file.close()
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await self._build_file(self.__mmdb)
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self.not_running = True
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del self.__mmdb
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del self.__loop
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del self.__queue
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del self.__file
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del self.__buffer
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del self.__task
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del self.__initial_size
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async def complete_transaction(self, delta: dict):
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buffer = StringIO()
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self.db2io(delta, buffer)
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self.__mmdb.update(delta)
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future = self.__loop.create_future()
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self.__queue.put_nowait(TransactionRequest(buffer, future))
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await future
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async def commit(self):
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future = self.__loop.create_future()
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self.__queue.put_nowait(DumpRequest(future))
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await future
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def transaction(self) -> 'Transaction':
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return Transaction(self)
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class DbFactory:
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def __init__(self, path: str | pathlib.Path, *, kvrequest_type: Type[KVRequest], buffersize=1048576):
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self.path = path = str(path)
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self.kvrequest_type = kvrequest_type
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self.buffersize = buffersize
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async def __aenter__(self) -> DbConnection:
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self.db = await DbConnection.create(self)
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return self.db
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async def __aexit__(self, exc_type, exc_val, exc_tb):
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await self.db.aclose()
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class Db(DbFactory, DbConnection):
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def __init__(self, path: str | pathlib.Path, *, kvrequest_type: Type[KVRequest], buffersize=1048576):
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DbFactory.__init__(self, path, kvrequest_type=kvrequest_type, buffersize=buffersize)
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DbConnection.__init__(self, self)
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async def __aenter__(self) -> DbConnection:
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await self._initialize()
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return self
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async def __aexit__(self, exc_type, exc_val, exc_tb):
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await self.aclose()
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class FallbackMapping:
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def __init__(self, delta: dict, connection: DbConnection) -> None:
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self.__delta = delta
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self.__connection = connection
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def get(self, key: Any, default: Any):
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return self.__delta.get(key, self.__connection.get(key, default))
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def set_nowait(self, key: Any, value: Any):
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self.__delta[key] = value
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class Transaction:
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delta: dict
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def __init__(self, connection: DbConnection) -> None:
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self.connection = connection
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async def __aenter__(self) -> FallbackMapping:
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self.delta = {}
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return FallbackMapping(self.delta, self.connection)
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async def __aexit__(self, exc_type, exc_val, exc_tb):
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if exc_type is None:
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await self.connection.complete_transaction(self.delta)
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del self.delta
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