LruCache.evict() also prunes cache by maximum age

Signed-off-by: flashdagger <flashdagger@googlemail.com>

tests/test_cache.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: UTF-8 -*-
 
+import time
 from itertools import zip_longest
 from operator import eq
 
@@ -158,9 +159,6 @@ def test_clear():
 
 
 def test_age_s():
-    import time
-    from datetime import datetime, timezone
-
     cache = LruCache()
     assert cache.age_s("foo") is None
 
@@ -170,3 +168,16 @@ def test_age_s():
     assert cache.age_s("foo") > 0.015
     cache["foo"] = "baz"
     assert cache.age_s("foo") < 0.015
+
+
+def test_evict_by_age():
+    cache = LruCache()
+    cache["first"] = None
+    time.sleep(0.015)
+    cache["second"] = None
+
+    cache.evict()
+    assert cache.keys() == {"first", "second"}
+
+    cache.evict(max_age_s=0.015)
+    assert cache.keys() == {"second"}

zammadoo/cache.py

@@ -3,7 +3,7 @@
 from collections import OrderedDict
 from collections.abc import Hashable
 from time import monotonic
-from typing import Generic, Optional, Tuple, TypeVar
+from typing import Generic, Optional, Tuple, TypeVar, Union
 
 _T = TypeVar("_T")
 
@@ -22,12 +22,18 @@ def max_size(self, value: int):
         self._max_size = max(value, -1)
         self.evict()
 
-    def evict(self) -> None:
+    def evict(self, max_age_s: Union[None, int, float] = None) -> None:
+        cache = self._cache
+        if max_age_s is not None:
+            min_timestamp = monotonic() - max_age_s
+            outdated = [key for key, value in cache.items() if value[0] < min_timestamp]
+            for key in outdated:
+                del cache[key]
+
         max_size = self._max_size
         if max_size < 0:
             return
 
-        cache = self._cache
         if max_size == 0:
             cache.clear()
             return