Add cacheing

app/authentication/auth.py

@@ -100,6 +100,7 @@ def get_service_dict(issuer):
     return service_schema.dump(fetched).data
 
 
+@SerialisedService.cache
 def get_service_model(issuer):
     return SerialisedService(get_service_dict(issuer))
 
@@ -111,6 +112,7 @@ def get_api_keys_dict(issuer):
     ]
 
 
+@SerialisedAPIKeyCollection.cache
 def get_api_keys_models(issuer):
     return SerialisedAPIKeyCollection(get_api_keys_dict(issuer))
 

app/notifications/validators.py

@@ -167,6 +167,7 @@ def get_template_dict(template_id, service_id):
     return template_dict
 
 
+@SerialisedTemplate.cache
 def get_template_model(template_id, service_id):
     return SerialisedTemplate(get_template_dict(template_id, service_id))
 

app/serialised_models.py

@@ -1,7 +1,27 @@
 from abc import ABC, abstractmethod
+from collections import defaultdict
+from functools import partial
+from threading import RLock
+
+import cachetools
+
+caches = defaultdict(partial(cachetools.TTLCache, maxsize=1024, ttl=2))
+locks = defaultdict(RLock)
 
 
-class SerialisedModel(ABC):
+class CacheMixin:
+
+    @classmethod
+    def cache(cls, func):
+
+        @cachetools.cached(cache=caches[cls.__name__], lock=locks[cls.__name__])
+        def wrapper(*args, **kwargs):
+            return func(*args, **kwargs)
+
+        return wrapper
+
+
+class SerialisedModel(ABC, CacheMixin):
 
     """
     A SerialisedModel takes a dictionary, typically created by
@@ -24,7 +44,7 @@ class SerialisedModel(ABC):
         return super().__dir__() + list(sorted(self.ALLOWED_PROPERTIES))
 
 
-class SerialisedModelCollection(ABC):
+class SerialisedModelCollection(ABC, CacheMixin):
 
     """
     A SerialisedModelCollection takes a list of dictionaries, typically

tests/app/authentication/test_authentication.py

@@ -8,11 +8,13 @@ import pytest
 from flask import json, current_app, request
 from freezegun import freeze_time
 from notifications_python_client.authentication import create_jwt_token
+from unittest.mock import call
 
 from app import api_user
 from app.dao.api_key_dao import get_unsigned_secrets, save_model_api_key, get_unsigned_secret, expire_api_key
 from app.models import ApiKey, KEY_TYPE_NORMAL
 from app.authentication.auth import AuthError, requires_admin_auth, requires_auth, GENERAL_TOKEN_ERROR_MESSAGE
+from app.serialised_models import caches, get_model_api_keys, dao_fetch_service_by_id
 
 from tests.conftest import set_config
 
@@ -457,3 +459,34 @@ def test_proxy_key_on_admin_auth_endpoint(notify_api, check_proxy_header, header
                 ]
             )
         assert response.status_code == expected_status
+
+
+def test_should_cache_service_and_api_key_lookups(mocker, client, sample_api_key):
+
+    mock_get_api_keys = mocker.patch(
+        'app.serialised_models.get_model_api_keys',
+        wraps=get_model_api_keys,
+    )
+    mock_get_service = mocker.patch(
+        'app.serialised_models.dao_fetch_service_by_id',
+        wraps=dao_fetch_service_by_id,
+    )
+
+    for i in range(5):
+        token = __create_token(sample_api_key.service_id)
+        client.get('/notifications', headers={
+            'Authorization': f'Bearer {token}'
+        })
+
+    assert mock_get_api_keys.call_args_list == [
+        call(str(sample_api_key.service_id))
+    ]
+    assert mock_get_service.call_args_list == [
+        call(str(sample_api_key.service_id))
+    ]
+
+    assert caches['SerialisedService.from_id'].currsize == 1
+    assert caches['SerialisedService.from_id'].ttl == 2
+
+    assert caches['SerialisedAPIKeyCollection.from_service_id'].currsize == 1
+    assert caches['SerialisedAPIKeyCollection.from_service_id'].ttl == 2