Depend on cachetools instead of implementing our own cache

More robust (but pure TTL) cache set up, with same 128 maxsize.
https://cachetools.readthedocs.io/en/stable/ has more options
we can switch to if needed.

Author: yuvipanda

pyproject.toml

@@ -13,6 +13,7 @@ dependencies = [
     "prometheus-client~=0.24",
     "requests>=2.32.4",
     "yarl>=1.20.1",
+    "cachetools"
 ]
 
 [dependency-groups]

src/jupyterhub_cost_monitoring/cache.py

@@ -6,10 +6,10 @@
 import functools
 from pprint import pformat
 
+from cachetools.func import ttl_cache
 import boto3
 import requests
 
-from .cache import ttl_lru_cache
 from .const_cost_aws import (
     FILTER_ATTRIBUTABLE_COSTS,
     FILTER_CORE_COSTS,
@@ -64,7 +64,7 @@ def query_aws_cost_explorer(metrics, granularity, from_date, to_date, filter, gr
     return response
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_hub_names(date_range: DateRange):
     """
     Query hub names from AWS Cost Explorer within the given date range.
@@ -87,7 +87,7 @@ def query_hub_names(date_range: DateRange):
     return hub_names
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_total_costs(date_range: DateRange):
     """
     Query total costs from AWS Cost Explorer for the given date range.
@@ -119,7 +119,7 @@ def query_total_costs(date_range: DateRange):
     return processed_response
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def _query_total_costs(date_range: DateRange, add_attributable_costs_filter):
     """
     Internal function to query total costs from AWS Cost Explorer.
@@ -169,7 +169,7 @@ def _query_total_costs(date_range: DateRange, add_attributable_costs_filter):
     return processed_response
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_total_costs_per_hub(date_range: DateRange):
     """
     Query total costs per hub from AWS Cost Explorer for the given date range.
@@ -378,7 +378,7 @@ def _process_core_costs(entries_by_date, core_cost_response):
                 logger.debug(f"Added new core entry for {date}: {core_cost:.2f}")
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_total_costs_per_component(
     date_range: DateRange,
     hub_name: str = None,
@@ -513,7 +513,7 @@ def query_total_costs_per_component(
     return final_response
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_total_costs_per_user(
     date_range: DateRange,
     hub: str = None,
@@ -629,7 +629,7 @@ def query_total_costs_per_user(
     return results
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_total_costs_per_group(
     date_range: DateRange,
 ):

src/jupyterhub_cost_monitoring/query_cost_aws.py

@@ -10,7 +10,7 @@
 import requests
 from yarl import URL
 
-from .cache import ttl_lru_cache
+from cachetools.func import ttl_cache
 from .const_usage import USAGE_MAP, USER_GROUP_INFO
 from .date_utils import DateRange, get_now_date
 from .logs import get_logger
@@ -255,7 +255,7 @@ def _calculate_daily_cost_factors(
     return result
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_user_groups(
     hub_name: str | None = None,
     user_name: str | None = None,
@@ -305,7 +305,7 @@ def _process_user_groups(
     return result
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_users_with_multiple_groups(
     date_range: DateRange,
     hub_name: str | None = None,
@@ -339,7 +339,7 @@ def query_users_with_multiple_groups(
     return result
 
 
-@ttl_lru_cache(seconds_to_live=3600)
+@ttl_cache(ttl=3600)
 def query_users_with_no_groups(
     date_range: DateRange,
     hub_name: str | None = None,

src/jupyterhub_cost_monitoring/query_usage.py

@@ -10,7 +10,7 @@
 
 import pytest
 
-from src.jupyterhub_cost_monitoring.cache import ttl_lru_cache
+from src.jupyterhub_cost_monitoring.cache import ttl_cache
 from src.jupyterhub_cost_monitoring.date_utils import (
     DateRange,
     ensure_utc_datetime,
@@ -229,14 +229,14 @@ def test_timezone_handling_in_parsing(self):
 
 
 class TestCacheIntegration:
-    """Test DateRange compatibility with ttl_lru_cache."""
+    """Test DateRange compatibility with ttl_cache."""
 
     def test_daterange_as_cache_key(self):
         """Test that DateRange objects work as cache keys."""
 
         call_count = 0
 
-        @ttl_lru_cache(seconds_to_live=300)
+        @ttl_cache(ttl=300)
         def cached_function(date_range: DateRange) -> str:
             nonlocal call_count
             call_count += 1
@@ -261,7 +261,7 @@ def test_cache_miss_with_different_ranges(self):
         """Test that different DateRange objects result in cache misses."""
         call_count = 0
 
-        @ttl_lru_cache(seconds_to_live=300)
+        @ttl_cache(ttl=300)
         def cached_function(date_range: DateRange) -> str:
             nonlocal call_count
             call_count += 1
@@ -286,7 +286,7 @@ def test_cache_hit_with_same_dates_different_times(self):
         """Test that DateRange objects with same dates but different times result in cache hits."""
         call_count = 0
 
-        @ttl_lru_cache(seconds_to_live=300)
+        @ttl_cache(ttl=300)
         def cached_function(date_range: DateRange) -> str:
             nonlocal call_count
             call_count += 1