Merge pull request #2891 from alphagov/cache-serialised-template

Cache serialised template in Redis and in memory

app/schemas.py

@@ -13,6 +13,7 @@ from marshmallow import (
     post_dump
 )
 from marshmallow_sqlalchemy import field_for
+from uuid import UUID
 
 from notifications_utils.recipients import (
     validate_email_address,
@@ -58,6 +59,14 @@ def _validate_datetime_not_in_past(dte, msg="Date cannot be in the past"):
         raise ValidationError(msg)
 
 
+class UUIDsAsStringsMixin:
+    @post_dump()
+    def __post_dump(self, data):
+        for key, value in data.items():
+            if isinstance(value, UUID):
+                data[key] = str(value)
+
+
 class BaseSchema(ma.ModelSchema):
 
     def __init__(self, load_json=False, *args, **kwargs):
@@ -341,7 +350,7 @@ class BaseTemplateSchema(BaseSchema):
         strict = True
 
 
-class TemplateSchema(BaseTemplateSchema):
+class TemplateSchema(BaseTemplateSchema, UUIDsAsStringsMixin):
 
     created_by_id = field_for(
         models.Template, 'created_by_id', dump_to='created_by', dump_only=True

app/serialised_models.py

@@ -1,7 +1,34 @@
 from abc import ABC, abstractmethod
+from collections import defaultdict
+from functools import partial
+from threading import RLock
 
+import cachetools
+from notifications_utils.clients.redis import RequestCache
+
+from app import redis_store
 from app.dao import templates_dao
 
+caches = defaultdict(partial(cachetools.TTLCache, maxsize=1024, ttl=2))
+locks = defaultdict(RLock)
+redis_cache = RequestCache(redis_store)
+
+
+def memory_cache(func):
+    @cachetools.cached(
+        cache=caches[func.__qualname__],
+        lock=locks[func.__qualname__],
+        key=ignore_first_argument_cache_key,
+    )
+    def wrapper(*args, **kwargs):
+        return func(*args, **kwargs)
+
+    return wrapper
+
+
+def ignore_first_argument_cache_key(cls, *args, **kwargs):
+    return cachetools.keys.hashkey(*args, **kwargs)
+
 
 class SerialisedModel(ABC):
 
@@ -40,10 +67,12 @@ class SerialisedTemplate(SerialisedModel):
     }
 
     @classmethod
+    @memory_cache
     def from_id_and_service_id(cls, template_id, service_id):
         return cls(cls.get_dict(template_id, service_id))
 
     @staticmethod
+    @redis_cache.set('template-{template_id}-version-None')
     def get_dict(template_id, service_id):
         from app.schemas import template_schema
 

tests/app/v2/notifications/test_post_notifications.py

@@ -6,6 +6,7 @@ import pytest
 from freezegun import freeze_time
 from boto.exception import SQSError
 
+from app.dao import templates_dao
 from app.dao.service_sms_sender_dao import dao_update_service_sms_sender
 from app.models import (
     ScheduledNotification,
@@ -211,6 +212,105 @@ def test_notification_reply_to_text_is_original_value_if_sender_is_changed_after
     assert notifications[0].reply_to_text == '123456'
 
 
+def test_should_cache_template_lookups_in_memory(mocker, client, sample_template):
+
+    mock_get_template = mocker.patch(
+        'app.dao.templates_dao.dao_get_template_by_id_and_service_id',
+        wraps=templates_dao.dao_get_template_by_id_and_service_id,
+    )
+    mocker.patch('app.celery.provider_tasks.deliver_sms.apply_async')
+
+    data = {
+        'phone_number': '+447700900855',
+        'template_id': str(sample_template.id),
+    }
+
+    for i in range(5):
+        auth_header = create_authorization_header(service_id=sample_template.service_id)
+        client.post(
+            path='/v2/notifications/sms',
+            data=json.dumps(data),
+            headers=[('Content-Type', 'application/json'), auth_header]
+        )
+
+    assert mock_get_template.call_count == 1
+    assert mock_get_template.call_args_list == [
+        call(service_id=sample_template.service_id, template_id=str(sample_template.id))
+    ]
+    assert Notification.query.count() == 5
+
+
+def test_should_cache_template_lookups_in_redis(mocker, client, sample_template):
+
+    from app.schemas import template_schema
+
+    mock_redis_get = mocker.patch(
+        'app.redis_store.get',
+        return_value=None,
+    )
+    mock_redis_set = mocker.patch(
+        'app.redis_store.set',
+    )
+
+    mocker.patch('app.celery.provider_tasks.deliver_sms.apply_async')
+
+    data = {
+        'phone_number': '+447700900855',
+        'template_id': str(sample_template.id),
+    }
+
+    auth_header = create_authorization_header(service_id=sample_template.service_id)
+    client.post(
+        path='/v2/notifications/sms',
+        data=json.dumps(data),
+        headers=[('Content-Type', 'application/json'), auth_header]
+    )
+
+    expected_key = f'template-{sample_template.id}-version-None'
+
+    assert mock_redis_get.call_args_list == [call(
+        expected_key,
+    )]
+
+    template_dict = template_schema.dump(sample_template).data
+
+    assert len(mock_redis_set.call_args_list) == 1
+    assert mock_redis_set.call_args[0][0] == expected_key
+    assert json.loads(mock_redis_set.call_args[0][1]) == template_dict
+    assert mock_redis_set.call_args[1]['ex'] == 604_800
+
+
+def test_should_return_template_if_found_in_redis(mocker, client, sample_template):
+
+    from app.schemas import template_schema
+    template_dict = template_schema.dump(sample_template).data
+
+    mocker.patch(
+        'app.redis_store.get',
+        return_value=json.dumps(template_dict).encode('utf-8')
+    )
+    mock_get_template = mocker.patch(
+        'app.dao.templates_dao.dao_get_template_by_id_and_service_id'
+    )
+
+    mocker.patch('app.celery.provider_tasks.deliver_sms.apply_async')
+
+    data = {
+        'phone_number': '+447700900855',
+        'template_id': str(sample_template.id),
+    }
+
+    auth_header = create_authorization_header(service_id=sample_template.service_id)
+    response = client.post(
+        path='/v2/notifications/sms',
+        data=json.dumps(data),
+        headers=[('Content-Type', 'application/json'), auth_header]
+    )
+
+    assert response.status_code == 201
+    assert mock_get_template.called is False
+
+
 @pytest.mark.parametrize("notification_type, key_send_to, send_to",
                          [("sms", "phone_number", "+447700900855"),
                           ("email", "email_address", "sample@email.com")])