Merge branch 'release/1.5.0'

.changes/1.5.0.json

@@ -0,0 +1,6 @@
+[
+  {
+    "description": "Make use of ExpiringDict to limit memory usage in cache",
+    "type": "minor"
+  }
+]

AUTHORS

@@ -1,4 +1,4 @@
-   811	Fabian Schuh <[email protected]>
+   817	Fabian Schuh <[email protected]>
    167	Fabian Schuh <[email protected]>
    104	Vladimir Kamarzin <[email protected]>
    100	Fabian Schuh <[email protected]>

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 Note: version releases in the 0.x.y range may introduce breaking changes.
 
+## 1.5.0
+
+- minor: Make use of ExpiringDict to limit memory usage in cache
+
 ## 1.4.4
 
 - patch: Make the caching key explicit

graphenecommon/objectcache.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 from datetime import datetime, timedelta
 from abc import ABC, abstractmethod, abstractproperty
+from expiringdict import ExpiringDict
 
 
 class ObjectCacheInterface:
@@ -34,54 +35,33 @@ def __str__(self):
         )
 
 
-class ObjectCacheInMemory(ObjectCacheInterface, dict):
+class ObjectCacheInMemory(ExpiringDict, ObjectCacheInterface):
     """ This class implements an object/dict cache that comes with an
-        expiration. Expired items are removed from the cache.
+        expiration. Expired items are removed from the cache. The cache has a
+        max_length.
     """
 
-    def __init__(self, initial_data={}, default_expiration=60, no_overwrite=False):
+    def __init__(
+        self,
+        initial_data={},
+        default_expiration=60,
+        no_overwrite=False,
+        max_length=1000,
+    ):
         dict.__init__(self, initial_data)
 
         # Expiration
-        self.set_expiration(default_expiration)
+        self.default_expiration = default_expiration
 
         # This allows nicer testing
         self.no_overwrite = no_overwrite
 
-    def __setitem__(self, key, value):
-        if key in self and not self.no_overwrite:
-            del self[key]
-        elif key in self and self.no_overwrite:
-            return
-        data = {
-            "expires": datetime.utcnow() + timedelta(seconds=self.default_expiration),
-            "data": value,
-        }
-        dict.__setitem__(self, key, data)
-
-    def __getitem__(self, key):
-        """ Returns an element from the cache if available, else returns
-            the value provided as default or None
-        """
-        if key in self:
-            value = dict.__getitem__(self, key)
-            return value["data"]
+        # Number of items to store (in total)
+        self._max_items = max_length
 
-    def get(self, key, default_value=None):
-        if key in self:
-            return self[key]
-        else:
-            return default_value
-
-    def __contains__(self, key):
-        if dict.__contains__(self, key):
-            value = dict.__getitem__(self, key)
-            if datetime.utcnow() < value["expires"]:
-                return True
-            else:
-                # Remove from cache
-                dict.pop(self, key, None)
-        return False
+        ExpiringDict.__init__(
+            self, max_len=self._max_items, max_age_seconds=self.default_expiration
+        )
 
     def set_expiration(self, expiration):
         """ Set new default expiration time in seconds (default: 10s)

requirements.txt

@@ -8,3 +8,4 @@ scrypt>=0.8.13,<0.9
 websockets>=8.1,<9
 aiohttp>=3.5.4,<4
 asyncinit>=0.2.4,<0.3
+expiringdict

setup.py

@@ -3,7 +3,7 @@
 
 from setuptools import setup
 
-__version__ = "1.4.4"
+__version__ = "1.5.0"
 URL = "https://github.com/xeroc/python-graphenelib"
 
 setup(

tests/test_objectcache.py

@@ -24,6 +24,20 @@ def test_cache(self):
         # Get
         self.assertEqual(cache.get("foo", "New"), "New")
 
+    def test_max_length_cache(self):
+        cache = ObjectCacheInMemory(default_expiration=1, max_length=10)
+        self.assertEqual(str(cache), "ObjectCacheInMemory(default_expiration=1)")
+
+        for num in range(0, 10):
+            cache[str(num)] = "bar"
+
+        self.assertEqual(len(cache), 10)
+
+        for num in range(11, 50):
+            cache[str(num)] = "bar"
+
+        self.assertEqual(len(cache), 10)
+
     def test_cache_list(self):
         cache = ObjectCacheInMemory(default_expiration=1)
         self.assertEqual(str(cache), "ObjectCacheInMemory(default_expiration=1)")