Simplify deleting old letters

Previously we made a call to S3 to list objects for a letter, even
though we already had the precise key of the single object to hand.
This removes the one usage of "get_s3_bucket_objects" and uses the
filename directly in the call to remove the object.

app/aws/s3.py

@@ -69,22 +69,6 @@ def remove_contact_list_from_s3(service_id, contact_list_id):
     return remove_s3_object(*get_contact_list_location(service_id, contact_list_id))
 
 
-def get_s3_bucket_objects(bucket_name, subfolder=''):
-    boto_client = client('s3', current_app.config['AWS_REGION'])
-    paginator = boto_client.get_paginator('list_objects_v2')
-    page_iterator = paginator.paginate(
-        Bucket=bucket_name,
-        Prefix=subfolder
-    )
-
-    all_objects_in_bucket = []
-    for page in page_iterator:
-        if page.get('Contents'):
-            all_objects_in_bucket.extend(page['Contents'])
-
-    return all_objects_in_bucket
-
-
 def remove_s3_object(bucket_name, object_key):
     obj = get_s3_object(bucket_name, object_key)
     return obj.delete()

app/dao/notifications_dao.py

@@ -22,7 +22,7 @@ from sqlalchemy.sql.expression import case
 from werkzeug.datastructures import MultiDict
 
 from app import create_uuid, db
-from app.aws.s3 import get_s3_bucket_objects, remove_s3_object
+from app.aws.s3 import remove_s3_object
 from app.clients.sms.firetext import (
     get_message_status_and_reason_from_firetext_code,
 )
@@ -454,19 +454,11 @@ def _delete_letters_from_s3(
     ).limit(query_limit).all()
     for letter in letters_to_delete_from_s3:
         try:
-            prefix = find_letter_pdf_filename(letter)
-        except LetterPDFNotFound:
+            filename = find_letter_pdf_filename(letter)
+            remove_s3_object(bucket_name, filename)
+        except (ClientError, LetterPDFNotFound):
             current_app.logger.exception(
                 "Could not delete S3 object for letter: {}".format(letter.id))
-            continue
-
-        s3_objects = get_s3_bucket_objects(bucket_name=bucket_name, subfolder=prefix)
-        for s3_object in s3_objects:
-            try:
-                remove_s3_object(bucket_name, s3_object['Key'])
-            except ClientError:
-                current_app.logger.exception(
-                    "Could not delete S3 object with filename: {}".format(s3_object['Key']))
 
 
 @transactional

tests/app/aws/test_s3.py

@@ -1,15 +1,10 @@
 from datetime import datetime, timedelta
-from unittest.mock import call
 
 import pytest
 import pytz
 from freezegun import freeze_time
 
-from app.aws.s3 import (
-    get_list_of_files_by_suffix,
-    get_s3_bucket_objects,
-    get_s3_file,
-)
+from app.aws.s3 import get_list_of_files_by_suffix, get_s3_file
 from tests.app.conftest import datetime_in_past
 
 
@@ -31,39 +26,6 @@ def test_get_s3_file_makes_correct_call(notify_api, mocker):
     )
 
 
-def test_get_s3_bucket_objects_make_correct_pagination_call(notify_api, mocker):
-    paginator_mock = mocker.patch('app.aws.s3.client')
-
-    get_s3_bucket_objects('foo-bucket', subfolder='bar')
-
-    paginator_mock.assert_has_calls([
-        call().get_paginator().paginate(Bucket='foo-bucket', Prefix='bar')
-    ])
-
-
-def test_get_s3_bucket_objects_builds_objects_list_from_paginator(notify_api, mocker):
-    AFTER_SEVEN_DAYS = datetime_in_past(days=8)
-    paginator_mock = mocker.patch('app.aws.s3.client')
-    multiple_pages_s3_object = [
-        {
-            "Contents": [
-                single_s3_object_stub('bar/foo.txt', AFTER_SEVEN_DAYS),
-            ]
-        },
-        {
-            "Contents": [
-                single_s3_object_stub('bar/foo1.txt', AFTER_SEVEN_DAYS),
-            ]
-        }
-    ]
-    paginator_mock.return_value.get_paginator.return_value.paginate.return_value = multiple_pages_s3_object
-
-    bucket_objects = get_s3_bucket_objects('foo-bucket', subfolder='bar')
-
-    assert len(bucket_objects) == 2
-    assert set(bucket_objects[0].keys()) == set(['ETag', 'Key', 'LastModified'])
-
-
 @freeze_time("2018-01-11 00:00:00")
 @pytest.mark.parametrize('suffix_str, days_before, returned_no', [
     ('.ACK.txt', None, 1),

tests/app/dao/notification_dao/test_notification_dao_delete_notifications.py

@@ -73,7 +73,7 @@ def test_should_delete_notifications_by_type_after_seven_days(
         expected_letter_count
 ):
     mocker.patch("app.dao.notifications_dao.find_letter_pdf_filename")
-    mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
+    mocker.patch("app.dao.notifications_dao.remove_s3_object")
     email_template, letter_template, sms_template = _create_templates(sample_service)
     # create one notification a day between 1st and 10th from 11:00 to 19:00 of each type
     for i in range(1, 11):
@@ -107,7 +107,6 @@ def test_should_delete_notifications_by_type_after_seven_days(
 
 @freeze_time("2016-01-10 12:00:00.000000")
 def test_should_not_delete_notification_history(sample_service, mocker):
-    mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
     with freeze_time('2016-01-01 12:00'):
         email_template, letter_template, sms_template = _create_templates(sample_service)
         create_notification(template=email_template, status='permanent-failure')
@@ -122,16 +121,16 @@ def test_should_not_delete_notification_history(sample_service, mocker):
 @pytest.mark.parametrize('notification_type', ['sms', 'email', 'letter'])
 def test_delete_notifications_for_days_of_retention(sample_service, notification_type, mocker):
     mocker.patch('app.dao.notifications_dao.find_letter_pdf_filename')
-    mock_get_s3 = mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
+    mock_remove_s3 = mocker.patch("app.dao.notifications_dao.remove_s3_object")
     create_test_data(notification_type, sample_service)
     assert Notification.query.count() == 9
     delete_notifications_older_than_retention_by_type(notification_type)
     assert Notification.query.count() == 7
     assert Notification.query.filter_by(notification_type=notification_type).count() == 1
     if notification_type == 'letter':
-        assert mock_get_s3.call_count == 2
+        assert mock_remove_s3.call_count == 2
     else:
-        mock_get_s3.assert_not_called()
+        mock_remove_s3.assert_not_called()
 
 
 @mock_s3
@@ -171,7 +170,6 @@ def test_delete_notifications_inserts_notification_history(sample_service):
 def test_delete_notifications_does_nothing_if_notification_history_row_already_exists(
     sample_email_template, mocker
 ):
-    mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
     notification = create_notification(
         template=sample_email_template, created_at=datetime.utcnow() - timedelta(days=8),
         status='temporary-failure'
@@ -197,7 +195,6 @@ def test_delete_notifications_keep_data_for_days_of_retention_is_longer(sample_s
 
 
 def test_delete_notifications_with_test_keys(sample_template, mocker):
-    mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
     create_notification(template=sample_template, key_type='test', created_at=datetime.utcnow() - timedelta(days=8))
     delete_notifications_older_than_retention_by_type('sms')
     assert Notification.query.count() == 0
@@ -230,7 +227,7 @@ def test_delete_notifications_delete_notification_type_for_default_time_if_no_da
 def test_delete_notifications_deletes_letters_not_sent_and_in_final_state_from_table_but_not_s3(
     sample_service, mocker, notification_status
 ):
-    mock_get_s3 = mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
+    mock_remove_s3 = mocker.patch("app.dao.notifications_dao.remove_s3_object")
     letter_template = create_template(service=sample_service, template_type='letter')
     create_notification(
         template=letter_template,
@@ -245,7 +242,7 @@ def test_delete_notifications_deletes_letters_not_sent_and_in_final_state_from_t
 
     assert Notification.query.count() == 0
     assert NotificationHistory.query.count() == 1
-    mock_get_s3.assert_not_called()
+    mock_remove_s3.assert_not_called()
 
 
 @mock_s3
@@ -292,7 +289,7 @@ def test_delete_notifications_deletes_letters_sent_and_in_final_state_from_table
 def test_delete_notifications_does_not_delete_letters_not_yet_in_final_state(
     sample_service, mocker, notification_status
 ):
-    mock_get_s3 = mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
+    mock_remove_s3 = mocker.patch("app.dao.notifications_dao.remove_s3_object")
     letter_template = create_template(service=sample_service, template_type='letter')
     create_notification(
         template=letter_template,
@@ -307,7 +304,7 @@ def test_delete_notifications_does_not_delete_letters_not_yet_in_final_state(
 
     assert Notification.query.count() == 1
     assert NotificationHistory.query.count() == 0
-    mock_get_s3.assert_not_called()
+    mock_remove_s3.assert_not_called()
 
 
 @freeze_time('2020-03-25 00:01')