database.py

import asyncpg


class DatabaseManager:
    _instance = None

    # Singleton design pattern
    def __new__(cls, *args, **kwargs):
        if not cls._instance:
            cls._instance = super().__new__(cls)
        return cls._instance

    def __init__(self, dsn):
        self.dsn = dsn
        self.pool = None

    async def connect(self):
        self.pool = await asyncpg.create_pool(dsn=self.dsn)

    async def close(self):
        await self.pool.close()

    async def execute(self, query, *args):
        async with self.pool.acquire() as conn:
            return await conn.execute(query, *args)

    async def fetch(self, query, *args):
        async with self.pool.acquire() as conn:
            return await conn.fetch(query, *args)

    async def fetchrow(self, query, *args):
        async with self.pool.acquire() as conn:
            return await conn.fetchrow(query, *args)

    async def transaction(self, queries):
        async with self.pool.acquire() as conn:
            async with conn.transaction():
                for query, *args in queries:
                    await conn.execute(query, *args)