Move periodicCache to Utils package

freqtrade/util/__init__.py

@@ -0,0 +1,2 @@
+# flake8: noqa: F401
+from freqtrade.util.periodic_cache import PeriodicCache

freqtrade/util/periodic_cache.py

@@ -0,0 +1,19 @@
+from datetime import datetime, timezone
+
+from cachetools import TTLCache
+
+
+class PeriodicCache(TTLCache):
+    """
+    Special cache that expires at "straight" times
+    A timer with ttl of 3600 (1h) will expire at every full hour (:00).
+    """
+
+    def __init__(self, maxsize, ttl, getsizeof=None):
+        def local_timer():
+            ts = datetime.now(timezone.utc).timestamp()
+            offset = (ts % ttl)
+            return ts - offset
+
+        # Init with smlight offset
+        super().__init__(maxsize=maxsize, ttl=ttl - 1e-5, timer=local_timer, getsizeof=getsizeof)