Async Cache: Create class-based async cache

3 files changed, 37 insertions, 24 deletions

diff --git a/bot/exts/info/doc.py b/bot/exts/info/doc.py
index 06dd4df63..ba443d817 100644
--- a/bot/exts/info/doc.py
+++ b/bot/exts/info/doc.py
@@ -22,7 +22,7 @@ from bot.bot import Bot
 from bot.constants import MODERATION_ROLES, RedirectOutput
 from bot.converters import ValidPythonIdentifier, ValidURL
 from bot.pagination import LinePaginator
-from bot.utils.cache import async_cache
+from bot.utils.cache import AsyncCache
 from bot.utils.messages import wait_for_deletion
 
 
@@ -66,6 +66,9 @@ WHITESPACE_AFTER_NEWLINES_RE = re.compile(r"(?<=\n\n)(\s+)")
 FAILED_REQUEST_RETRY_AMOUNT = 3
 NOT_FOUND_DELETE_DELAY = RedirectOutput.delete_delay
 
+# Async cache instance for docs cog
+async_cache = AsyncCache()
+
 
 class DocMarkdownConverter(MarkdownConverter):
     """Subclass markdownify's MarkdownCoverter to provide custom conversion methods."""
@@ -187,7 +190,7 @@ class Doc(commands.Cog):
         self.base_urls.clear()
         self.inventories.clear()
         self.renamed_symbols.clear()
-        async_cache.cache["get_symbol_embed"] = OrderedDict()
+        async_cache.clear()
 
         # Run all coroutines concurrently - since each of them performs a HTTP
         # request, this speeds up fetching the inventory data heavily.
diff --git a/bot/exts/utils/utils.py b/bot/exts/utils/utils.py
index 2a74af172..64d42c93e 100644
--- a/bot/exts/utils/utils.py
+++ b/bot/exts/utils/utils.py
@@ -15,7 +15,7 @@ from bot.constants import Channels, MODERATION_ROLES, STAFF_ROLES
 from bot.decorators import in_whitelist
 from bot.pagination import LinePaginator
 from bot.utils import messages
-from bot.utils.cache import async_cache
+from bot.utils.cache import AsyncCache
 
 log = logging.getLogger(__name__)
 
@@ -43,6 +43,9 @@ Namespaces are one honking great idea -- let's do more of those!
 
 ICON_URL = "https://www.python.org/static/opengraph-icon-200x200.png"
 
+# Async cache instance for PEPs
+async_cache = AsyncCache()
+
 
 class Utils(Cog):
     """A selection of utilities which don't have a clear category."""
diff --git a/bot/utils/cache.py b/bot/utils/cache.py
index 37c2b199c..d8ec64ec8 100644
--- a/bot/utils/cache.py
+++ b/bot/utils/cache.py
@@ -3,7 +3,7 @@ from collections import OrderedDict
 from typing import Any, Callable
 
 
-def async_cache(max_size: int = 128, arg_offset: int = 0) -> Callable:
+class AsyncCache:
     """
     LRU cache implementation for coroutines.
 
@@ -11,23 +11,30 @@ def async_cache(max_size: int = 128, arg_offset: int = 0) -> Callable:
 
     An offset may be optionally provided to be applied to the coroutine's arguments when creating the cache key.
     """
-    # Make global cache as dictionary to allow multiple function caches
-    async_cache.cache = {}
-
-    def decorator(function: Callable) -> Callable:
-        """Define the async_cache decorator."""
-        async_cache.cache[function.__name__] = OrderedDict()
-
-        @functools.wraps(function)
-        async def wrapper(*args) -> Any:
-            """Decorator wrapper for the caching logic."""
-            key = ':'.join(str(args[arg_offset:]))
-
-            if key not in async_cache.cache:
-                if len(async_cache.cache[function.__name__]) > max_size:
-                    async_cache.cache[function.__name__].popitem(last=False)
-
-                async_cache.cache[function.__name__][key] = await function(*args)
-            return async_cache.cache[function.__name__][key]
-        return wrapper
-    return decorator
+
+    def __init__(self):
+        self._cache = OrderedDict()
+
+    def __call__(self, max_size: int = 128, arg_offset: int = 0) -> Callable:
+        """Decorator for async cache."""
+
+        def decorator(function: Callable) -> Callable:
+            """Define the async cache decorator."""
+
+            @functools.wraps(function)
+            async def wrapper(*args) -> Any:
+                """Decorator wrapper for the caching logic."""
+                key = ':'.join(str(args[arg_offset:]))
+
+                if key not in self._cache:
+                    if len(self._cache) > max_size:
+                        self._cache.popitem(last=False)
+
+                    self._cache[key] = await function(*args)
+                return self._cache[key]
+            return wrapper
+        return decorator
+
+    def clear(self):
+        """Clear cache instance."""
+        self._cache.clear()