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Mutex TTL Cache accesses which can be accessed by multiple threads

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Apparently, cachetools is (intentionally) not threadsafe
when using the Caches directly.
It's therefore recommended to wrap these with an explicit lock to avoid
problems.

source: https://github.com/tkem/cachetools/issues/245

closes #7215
This commit is contained in:
Matthias 2022-08-16 19:43:41 +02:00
parent ea6bc47d7a
commit 0b0e7eaf96
2 changed files with 17 additions and 8 deletions
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24
freqtrade/exchange/exchange.py
View File

@ -116,6 +116,7 @@ class Exchange:
self._last_markets_refresh: int = 0
# Cache for 10 minutes ...
self._cache_lock = Lock()
self._fetch_tickers_cache: TTLCache = TTLCache(maxsize=2, ttl=60 * 10)
# Cache values for 1800 to avoid frequent polling of the exchange for prices
# Caching only applies to RPC methods, so prices for open trades are still
@ -1388,12 +1389,14 @@ class Exchange:
if not self.exchange_has('fetchBidsAsks'):
return {}
if cached:
tickers = self._fetch_tickers_cache.get('fetch_bids_asks')
with self._cache_lock:
tickers = self._fetch_tickers_cache.get('fetch_bids_asks')
if tickers:
return tickers
try:
tickers = self._api.fetch_bids_asks(symbols)
self._fetch_tickers_cache['fetch_bids_asks'] = tickers
with self._cache_lock:
self._fetch_tickers_cache['fetch_bids_asks'] = tickers
return tickers
except ccxt.NotSupported as e:
raise OperationalException(
@ -1414,12 +1417,14 @@ class Exchange:
:return: fetch_tickers result
"""
if cached:
tickers = self._fetch_tickers_cache.get('fetch_tickers')
with self._cache_lock:
tickers = self._fetch_tickers_cache.get('fetch_tickers')
if tickers:
return tickers
try:
tickers = self._api.fetch_tickers(symbols)
self._fetch_tickers_cache['fetch_tickers'] = tickers
with self._cache_lock:
self._fetch_tickers_cache['fetch_tickers'] = tickers
return tickers
except ccxt.NotSupported as e:
raise OperationalException(
@ -1528,7 +1533,8 @@ class Exchange:
cache_rate: TTLCache = self._entry_rate_cache if side == "entry" else self._exit_rate_cache
if not refresh:
rate = cache_rate.get(pair)
with self._cache_lock:
rate = cache_rate.get(pair)
# Check if cache has been invalidated
if rate:
logger.debug(f"Using cached {side} rate for {pair}.")
@ -1573,7 +1579,8 @@ class Exchange:
if rate is None:
raise PricingError(f"{name}-Rate for {pair} was empty.")
cache_rate[pair] = rate
with self._cache_lock:
cache_rate[pair] = rate
return rate
@ -1581,8 +1588,9 @@ class Exchange:
entry_rate = None
exit_rate = None
if not refresh:
entry_rate = self._entry_rate_cache.get(pair)
exit_rate = self._exit_rate_cache.get(pair)
with self._cache_lock:
entry_rate = self._entry_rate_cache.get(pair)
exit_rate = self._exit_rate_cache.get(pair)
if entry_rate:
logger.debug(f"Using cached buy rate for {pair}.")
if exit_rate:

1
freqtrade/optimize/hyperopt.py
View File

@ -483,6 +483,7 @@ class Hyperopt:
self.backtesting.exchange._api_async = None
self.backtesting.exchange.loop = None # type: ignore
self.backtesting.exchange._loop_lock = None # type: ignore
self.backtesting.exchange._cache_lock = None # type: ignore
# self.backtesting.exchange = None # type: ignore
self.backtesting.pairlists = None # type: ignore