maubot/maubot/lib/plugin_db.py
2022-03-27 19:35:54 +03:00

101 lines
4.0 KiB
Python

# maubot - A plugin-based Matrix bot system.
# Copyright (C) 2022 Tulir Asokan
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from __future__ import annotations
from contextlib import asynccontextmanager
import asyncio
from mautrix.util.async_db import Database, PostgresDatabase, Scheme, UpgradeTable
from mautrix.util.async_db.connection import LoggingConnection
from mautrix.util.logging import TraceLogger
remove_double_quotes = str.maketrans({'"': "_"})
class ProxyPostgresDatabase(Database):
scheme = Scheme.POSTGRES
_underlying_pool: PostgresDatabase
schema_name: str
_quoted_schema: str
_default_search_path: str
_conn_sema: asyncio.Semaphore
_max_conns: int
def __init__(
self,
pool: PostgresDatabase,
instance_id: str,
max_conns: int,
upgrade_table: UpgradeTable | None,
log: TraceLogger | None = None,
) -> None:
super().__init__(pool.url, upgrade_table=upgrade_table, log=log)
self._underlying_pool = pool
# Simple accidental SQL injection prevention.
# Doesn't have to be perfect, since plugin instance IDs can only be set by admins anyway.
self.schema_name = f"mbp_{instance_id.translate(remove_double_quotes)}"
self._quoted_schema = f'"{self.schema_name}"'
self._default_search_path = '"$user", public'
self._conn_sema = asyncio.BoundedSemaphore(max_conns)
self._max_conns = max_conns
async def start(self) -> None:
async with self._underlying_pool.acquire() as conn:
self._default_search_path = await conn.fetchval("SHOW search_path")
self.log.trace(f"Found default search path: {self._default_search_path}")
await conn.execute(f"CREATE SCHEMA IF NOT EXISTS {self._quoted_schema}")
await super().start()
async def stop(self) -> None:
for _ in range(self._max_conns):
try:
await asyncio.wait_for(self._conn_sema.acquire(), timeout=3)
except asyncio.TimeoutError:
self.log.warning(
"Failed to drain plugin database connection pool, "
"the plugin may be leaking database connections"
)
break
async def delete(self) -> None:
self.log.info(f"Deleting schema {self.schema_name} and all data in it")
try:
await self._underlying_pool.execute(
f"DROP SCHEMA IF EXISTS {self._quoted_schema} CASCADE"
)
except Exception:
self.log.warning("Failed to delete schema", exc_info=True)
@asynccontextmanager
async def acquire(self) -> LoggingConnection:
conn: LoggingConnection
async with self._conn_sema, self._underlying_pool.acquire() as conn:
await conn.execute(f"SET search_path = {self._quoted_schema}")
try:
yield conn
finally:
if not conn.wrapped.is_closed():
try:
await conn.execute(f"SET search_path = {self._default_search_path}")
except Exception:
self.log.exception("Error resetting search_path after use")
await conn.wrapped.close()
else:
self.log.debug("Connection was closed after use, not resetting search_path")
__all__ = ["ProxyPostgresDatabase"]