Files
api/shared.py

291 lines
9.5 KiB
Python

"""
Shared infrastructure: connection pools and sessions.
This module provides centralized, reusable connections for:
- Redis (async connection pool)
- aiohttp (shared ClientSession)
- SQLite (connection pool for frequently accessed databases)
Usage:
from shared import get_redis_client, get_aiohttp_session, get_sqlite_pool
"""
import asyncio
import logging
from typing import Optional, Dict
from contextlib import asynccontextmanager
import aiohttp
import redis.asyncio as redis_async
import redis as redis_sync
import aiosqlite
from lyric_search.sources import private
logger = logging.getLogger(__name__)
# =============================================================================
# Redis Connection Pool
# =============================================================================
_redis_async_pool: Optional[redis_async.ConnectionPool] = None
_redis_async_client: Optional[redis_async.Redis] = None
_redis_sync_client: Optional[redis_sync.Redis] = None
_redis_sync_client_decoded: Optional[redis_sync.Redis] = None
def _create_redis_pool() -> redis_async.ConnectionPool:
"""Create a shared Redis connection pool."""
return redis_async.ConnectionPool(
host="127.0.0.1",
port=6379,
password=private.REDIS_PW,
max_connections=50,
decode_responses=False, # Default; callers can decode as needed
)
def get_redis_async_pool() -> redis_async.ConnectionPool:
"""Get or create the shared async Redis connection pool."""
global _redis_async_pool
if _redis_async_pool is None:
_redis_async_pool = _create_redis_pool()
return _redis_async_pool
def get_redis_async_client() -> redis_async.Redis:
"""Get or create a shared async Redis client using the connection pool."""
global _redis_async_client
if _redis_async_client is None:
_redis_async_client = redis_async.Redis(connection_pool=get_redis_async_pool())
return _redis_async_client
def get_redis_sync_client(decode_responses: bool = True) -> redis_sync.Redis:
"""
Get or create a shared sync Redis client.
We maintain two separate clients: one with decode_responses=True,
one with decode_responses=False, since this setting affects all operations.
"""
global _redis_sync_client, _redis_sync_client_decoded
if decode_responses:
if _redis_sync_client_decoded is None:
_redis_sync_client_decoded = redis_sync.Redis(
host="127.0.0.1",
port=6379,
password=private.REDIS_PW,
decode_responses=True,
)
return _redis_sync_client_decoded
else:
if _redis_sync_client is None:
_redis_sync_client = redis_sync.Redis(
host="127.0.0.1",
port=6379,
password=private.REDIS_PW,
decode_responses=False,
)
return _redis_sync_client
async def close_redis_pools() -> None:
"""Close Redis connections. Call on app shutdown."""
global _redis_async_pool, _redis_async_client, _redis_sync_client, _redis_sync_client_decoded
if _redis_async_client:
await _redis_async_client.close()
_redis_async_client = None
if _redis_async_pool:
await _redis_async_pool.disconnect()
_redis_async_pool = None
if _redis_sync_client:
_redis_sync_client.close()
_redis_sync_client = None
if _redis_sync_client_decoded:
_redis_sync_client_decoded.close()
_redis_sync_client_decoded = None
logger.info("Redis connections closed")
# =============================================================================
# aiohttp Shared Session
# =============================================================================
_aiohttp_session: Optional[aiohttp.ClientSession] = None
async def get_aiohttp_session() -> aiohttp.ClientSession:
"""
Get or create a shared aiohttp ClientSession.
The session uses connection pooling internally (default: 100 connections).
"""
global _aiohttp_session
if _aiohttp_session is None or _aiohttp_session.closed:
timeout = aiohttp.ClientTimeout(total=30, connect=10)
connector = aiohttp.TCPConnector(
limit=100, # Total connection pool size
limit_per_host=30, # Max connections per host
ttl_dns_cache=300, # DNS cache TTL
keepalive_timeout=60,
)
_aiohttp_session = aiohttp.ClientSession(
timeout=timeout,
connector=connector,
)
logger.info("Created shared aiohttp session")
return _aiohttp_session
async def close_aiohttp_session() -> None:
"""Close the shared aiohttp session. Call on app shutdown."""
global _aiohttp_session
if _aiohttp_session and not _aiohttp_session.closed:
await _aiohttp_session.close()
_aiohttp_session = None
logger.info("aiohttp session closed")
# =============================================================================
# SQLite Connection Pool
# =============================================================================
class SQLitePool:
"""
Simple SQLite connection pool for async access.
Maintains a pool of connections per database file to avoid
opening/closing connections on every request.
"""
def __init__(self, max_connections: int = 5):
self._pools: Dict[str, asyncio.Queue] = {}
self._max_connections = max_connections
self._locks: Dict[str, asyncio.Lock] = {}
self._connection_counts: Dict[str, int] = {}
async def _get_pool(self, db_path: str) -> asyncio.Queue:
"""Get or create a connection pool for the given database."""
if db_path not in self._pools:
self._pools[db_path] = asyncio.Queue(maxsize=self._max_connections)
self._locks[db_path] = asyncio.Lock()
self._connection_counts[db_path] = 0
return self._pools[db_path]
@asynccontextmanager
async def connection(self, db_path: str, timeout: float = 5.0):
"""
Get a connection from the pool.
Usage:
async with sqlite_pool.connection("/path/to/db.db") as conn:
async with conn.execute("SELECT ...") as cursor:
...
"""
pool = await self._get_pool(db_path)
lock = self._locks[db_path]
conn: Optional[aiosqlite.Connection] = None
# Try to get an existing connection from the pool
try:
conn = pool.get_nowait()
except asyncio.QueueEmpty:
# No available connection, create one if under limit
async with lock:
if self._connection_counts[db_path] < self._max_connections:
conn = await aiosqlite.connect(db_path, timeout=timeout)
self._connection_counts[db_path] += 1
# If still no connection (at limit), wait for one
if conn is None:
conn = await asyncio.wait_for(pool.get(), timeout=timeout)
try:
# Verify connection is still valid
if conn is not None:
try:
await conn.execute("SELECT 1")
except Exception:
# Connection is broken, create a new one
try:
await conn.close()
except Exception:
pass
conn = await aiosqlite.connect(db_path, timeout=timeout)
yield conn
finally:
# Return connection to pool
if conn is not None:
try:
pool.put_nowait(conn)
except asyncio.QueueFull:
# Pool is full, close this connection
await conn.close()
async with lock:
self._connection_counts[db_path] -= 1
async def close_all(self) -> None:
"""Close all connections in all pools."""
for db_path, pool in self._pools.items():
while not pool.empty():
try:
conn = pool.get_nowait()
await conn.close()
except asyncio.QueueEmpty:
break
self._connection_counts[db_path] = 0
self._pools.clear()
self._locks.clear()
self._connection_counts.clear()
logger.info("SQLite pools closed")
# Global SQLite pool instance
_sqlite_pool: Optional[SQLitePool] = None
def get_sqlite_pool() -> SQLitePool:
"""Get the shared SQLite connection pool."""
global _sqlite_pool
if _sqlite_pool is None:
_sqlite_pool = SQLitePool(max_connections=5)
return _sqlite_pool
async def close_sqlite_pools() -> None:
"""Close all SQLite pools. Call on app shutdown."""
global _sqlite_pool
if _sqlite_pool:
await _sqlite_pool.close_all()
_sqlite_pool = None
# =============================================================================
# Lifecycle Management
# =============================================================================
async def startup() -> None:
"""Initialize all shared resources. Call on app startup."""
# Pre-warm Redis connection
client = get_redis_async_client()
await client.ping()
logger.info("Shared infrastructure initialized")
async def shutdown() -> None:
"""Clean up all shared resources. Call on app shutdown."""
await close_aiohttp_session()
await close_redis_pools()
await close_sqlite_pools()
logger.info("Shared infrastructure shutdown complete")