Utkarsh/issue 186

pv_site_api/cache.py

@@ -4,7 +4,7 @@
 import os
 from datetime import datetime, timedelta, timezone
 from functools import wraps
-
+from threading import Lock
 import psutil
 import structlog
 from pvsite_datamodel.read.user import get_user_by_email
@@ -17,33 +17,47 @@
 cache_time_seconds = int(os.getenv("CACHE_TIME_SECONDS", CACHE_TIME_SECONDS))
 delete_cache_time_seconds = int(os.getenv("DELETE_CACHE_TIME_SECONDS", DELETE_CACHE_TIME_SECONDS))
 
+cache_lock = Lock()
 
 def remove_old_cache(
-    last_updated: dict, response: dict, remove_cache_time_seconds: float = delete_cache_time_seconds
-):
-    """
-    Remove old cache entries from the cache
+        last_updated: dict,
+        response: dict,
+        remove_cache_time_seconds: float = delete_cache_time_seconds
+    ):
+        """
+        Remove old cache entries from the cache
+
+        :param last_updated: dict of last updatedtimes
+        :param response: dict of responses, same keys as last_updated
+        :param remove_cache_time_seconds: the amount of time, after which the cache should be removed
+        """
 
-    :param last_updated: dict of last updatedtimes
-    :param response: dict of responses, same keys as last_updated
-    :param remove_cache_time_seconds: the amount of time, after which the cache should be removed
-    """
-    now = datetime.now(tz=timezone.utc)
-    logger.info("Removing old cache entries")
-    keys_to_remove = []
-    for key, value in last_updated.items():
-        if now - timedelta(seconds=remove_cache_time_seconds) > value:
-            logger.debug(f"Removing {key} from cache, ({value})")
-            keys_to_remove.append(key)
-
-    for key in keys_to_remove:
-        last_updated.pop(key)
-        response.pop(key)
-
-    process = psutil.Process(os.getpid())
-    logger.debug(f"Memory is {process.memory_info().rss / 10 ** 6} MB")
-
-    return last_updated, response
+        now = datetime.now(tz=timezone.utc)
+        logger.info("Removing old cache entries")
+
+        """
+        To check if cache removal is needed 
+        """
+        if not any(now - timedelta(seconds=remove_cache_time_seconds) > value for value in last_updated.values()):
+            logger.debug("No old cache entries to remove, skipping.")
+            return last_updated, response
+
+        keys_to_remove = []
+
+        with cache_lock:
+            for key, value in last_updated.items():
+                if now - timedelta(seconds=remove_cache_time_seconds) > value:  
+                    logger.debug(f"Removing {key} from cache, ({value})")
+                    keys_to_remove.append(key)
+
+        for key in keys_to_remove:
+            last_updated.pop(key, None)         
+            response.pop(key, None)
+
+        process = psutil.Process(os.getpid())
+        logger.debug(f"Memory is {process.memory_info().rss / 10 ** 6} MB")
+
+        return last_updated, response
 
 
 def cache_response(func):