100 lines
3.1 KiB
Python
100 lines
3.1 KiB
Python
|
"""Redis cache helper for equipment data and rate limiting."""
|
||
|
|
|
||
|
|
import json
|
||
|
|
import logging
|
||
|
|
from typing import Any
|
||
|
|
|
||
|
|
import redis.asyncio as redis
|
||
|
|
|
||
|
|
from app.config import settings
|
||
|
|
|
||
|
|
logger = logging.getLogger(__name__)
|
||
|
|
|
||
|
|
_cache_client: redis.Redis | None = None
|
||
|
|
|
||
|
|
|
||
|
|
def _build_key(*parts: str) -> str:
|
||
|
|
"""Build a colon-separated Redis key."""
|
||
|
|
return ":".join(part.replace(":", "_") for part in parts)
|
||
|
|
|
||
|
|
|
||
|
|
async def get_cache() -> redis.Redis:
|
||
|
|
"""Return the Redis client singleton, creating it on first use."""
|
||
|
|
global _cache_client
|
||
|
|
if _cache_client is None:
|
||
|
|
_cache_client = redis.from_url(settings.REDIS_URL, decode_responses=True)
|
||
|
|
return _cache_client
|
||
|
|
|
||
|
|
|
||
|
|
async def set_cache(key: str, value: Any, ttl: int = 3600) -> None:
|
||
|
|
"""Store a JSON-serialisable value in Redis with a TTL."""
|
||
|
|
try:
|
||
|
|
client = await get_cache()
|
||
|
|
await client.setex(key, ttl, json.dumps(value))
|
||
|
|
except Exception as exc: # noqa: BLE001
|
||
|
|
logger.warning("Cache set failed for key=%s: %s", key, exc)
|
||
|
|
|
||
|
|
|
||
|
|
async def get_cached(key: str) -> Any | None:
|
||
|
|
"""Retrieve and JSON-deserialise a cached value."""
|
||
|
|
try:
|
||
|
|
client = await get_cache()
|
||
|
|
raw = await client.get(key)
|
||
|
|
if raw is None:
|
||
|
|
return None
|
||
|
|
return json.loads(raw)
|
||
|
|
except Exception as exc: # noqa: BLE001
|
||
|
|
logger.warning("Cache get failed for key=%s: %s", key, exc)
|
||
|
|
return None
|
||
|
|
|
||
|
|
|
||
|
|
async def delete_pattern(pattern: str) -> None:
|
||
|
|
"""Delete all keys matching a glob pattern."""
|
||
|
|
try:
|
||
|
|
client = await get_cache()
|
||
|
|
async for key in client.scan_iter(match=pattern, count=100):
|
||
|
|
await client.delete(key)
|
||
|
|
except Exception as exc: # noqa: BLE001
|
||
|
|
logger.warning("Cache delete_pattern failed for pattern=%s: %s", pattern, exc)
|
||
|
|
|
||
|
|
|
||
|
|
async def check_rate_limit(identifier: str, max_requests: int = 5, window: int = 60) -> bool:
|
||
|
|
"""Return True if the identifier is within the rate limit."""
|
||
|
|
try:
|
||
|
|
client = await get_cache()
|
||
|
|
key = _build_key("rate", identifier)
|
||
|
|
count = await client.incr(key)
|
||
|
|
if count == 1:
|
||
|
|
await client.expire(key, window)
|
||
|
|
return count <= max_requests
|
||
|
|
except Exception as exc: # noqa: BLE001
|
||
|
|
logger.warning("Rate limit check failed: %s", exc)
|
||
|
|
return True
|
||
|
|
|
||
|
|
|
||
|
|
async def ping_cache() -> bool:
|
||
|
|
"""Check if Redis is reachable."""
|
||
|
|
try:
|
||
|
|
client = await get_cache()
|
||
|
|
return bool(await client.ping())
|
||
|
|
except Exception:
|
||
|
|
return False
|
||
|
|
|
||
|
|
|
||
|
|
def equipment_list_key(page: int, category: str | None, sort: str | None, search: str | None) -> str:
|
||
|
|
"""Build the Redis cache key for an equipment list query."""
|
||
|
|
cat = category or "all"
|
||
|
|
srt = sort or "default"
|
||
|
|
srch = search or "all"
|
||
|
|
return _build_key("equipment", "list", str(page), cat, srt, srch)
|
||
|
|
|
||
|
|
|
||
|
|
def equipment_detail_key(item_id: int) -> str:
|
||
|
|
"""Build the Redis cache key for an equipment detail."""
|
||
|
|
return _build_key("equipment", "detail", str(item_id))
|
||
|
|
|
||
|
|
|
||
|
|
def equipment_categories_key() -> str:
|
||
|
|
"""Build the Redis cache key for the equipment categories list."""
|
||
|
|
return _build_key("equipment", "categories")
|