From ebbfd204726946a44da8b6c4b78fb98e9ed99194 Mon Sep 17 00:00:00 2001
From: Ben Thorner <ben.thorner@digital.cabinet-office.gov.uk>
Date: Mon, 21 Feb 2022 11:28:15 +0000
Subject: [PATCH] Make it easy to clear cache for all key formats

Having to submit the form for each choice separately slowed us down
during an incident where Redis was unavailable and came back with
stale data, which we had to clear manually.

Note: we don't want to use the "flush" feature in case there are other
keys in Redis, which may not be safe to remove.
---
 app/main/forms.py                           |  6 +++++-
 app/main/views/platform_admin.py            | 19 ++++++++++++++-----
 tests/app/main/views/test_platform_admin.py | 14 ++++++--------
 3 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/app/main/forms.py b/app/main/forms.py
index e76955779..f6f7412a2 100644
--- a/app/main/forms.py
+++ b/app/main/forms.py
@@ -2445,10 +2445,14 @@ class TemplateAndFoldersSelectionForm(Form):
 
 
 class ClearCacheForm(StripWhitespaceForm):
-    model_type = GovukRadiosField(
+    model_type = GovukCheckboxesField(
         'What do you want to clear today',
     )
 
+    def validate_model_type(self, field):
+        if not field.data:
+            raise ValidationError('Select at least one option')
+
 
 class GoLiveNotesForm(StripWhitespaceForm):
     request_to_go_live_notes = TextAreaField(
diff --git a/app/main/views/platform_admin.py b/app/main/views/platform_admin.py
index 1cfbeab97..10e43fb4b 100644
--- a/app/main/views/platform_admin.py
+++ b/app/main/views/platform_admin.py
@@ -420,18 +420,27 @@ def clear_cache():
     ])
 
     form = ClearCacheForm()
-    form.model_type.choices = [(key, key.replace('_', ' ').title()) for key in CACHE_KEYS]
+
+    form.model_type.choices = [
+        (key, key.replace('_', ' ').title()) for key in CACHE_KEYS
+    ]
 
     if form.validate_on_submit():
-        group_key = form.model_type.data
-        group = CACHE_KEYS[group_key]
+        group_keys = form.model_type.data
+        groups = map(CACHE_KEYS.get, group_keys)
+        patterns = list(itertools.chain(*groups))
 
         num_deleted = sum(
             redis_client.delete_cache_keys_by_pattern(pattern)
-            for pattern in group
+            for pattern in patterns
+        )
+
+        msg = (
+            f'Removed {num_deleted} objects '
+            f'across {len(patterns)} key formats '
+            f'for {", ".join(group_keys)}'
         )
 
-        msg = f'Removed {num_deleted} {group_key} objects across {len(group)} key formats'
         flash(msg, category='default')
 
     return render_template(
diff --git a/tests/app/main/views/test_platform_admin.py b/tests/app/main/views/test_platform_admin.py
index e965e7667..fb4cba007 100644
--- a/tests/app/main/views/test_platform_admin.py
+++ b/tests/app/main/views/test_platform_admin.py
@@ -735,7 +735,7 @@ def test_clear_cache_shows_form(
     page = client_request.get('main.clear_cache')
 
     assert not redis.delete_cache_keys_by_pattern.called
-    radios = {el['value'] for el in page.select('input[type=radio]')}
+    radios = {el['value'] for el in page.select('input[type=checkbox]')}
 
     assert radios == {
         'user',
@@ -753,8 +753,8 @@ def test_clear_cache_shows_form(
         call('service-????????-????-????-????-????????????-templates'),
         call('service-????????-????-????-????-????????????-template-????????-????-????-????-????????????-version-*'),
         call('service-????????-????-????-????-????????????-template-????????-????-????-????-????????????-versions'),
-    ], 'Removed 6 template objects across 3 key formats'),
-    ('service', [
+    ], 'Removed 6 objects across 3 key formats for template'),
+    (['service', 'organisation'], [
         call('has_jobs-????????-????-????-????-????????????'),
         call('service-????????-????-????-????-????????????'),
         call('service-????????-????-????-????-????????????-templates'),
@@ -762,16 +762,14 @@ def test_clear_cache_shows_form(
         call('service-????????-????-????-????-????????????-template-folders'),
         call('service-????????-????-????-????-????????????-returned-letters-statistics'),
         call('service-????????-????-????-????-????????????-returned-letters-summary'),
-    ], 'Removed 14 service objects across 7 key formats'),
-    ('organisation', [
         call('organisations'),
         call('domains'),
         call('live-service-and-organisation-counts'),
         call('organisation-????????-????-????-????-????????????-name'),
-    ], 'Removed 8 organisation objects across 4 key formats'),
+    ], 'Removed 22 objects across 11 key formats for service, organisation'),
     ('broadcast', [
         call('service-????????-????-????-????-????????????-broadcast-message-????????-????-????-????-????????????'),
-    ], 'Removed 2 broadcast objects across 1 key formats'),
+    ], 'Removed 2 objects across 1 key formats for broadcast'),
 ))
 def test_clear_cache_submits_and_tells_you_how_many_things_were_deleted(
     client_request,
@@ -807,7 +805,7 @@ def test_clear_cache_requires_option(
 
     page = client_request.post('main.clear_cache', _data={}, _expected_status=200)
 
-    assert normalize_spaces(page.find('span', class_='govuk-error-message').text) == 'Error: Select an option'
+    assert normalize_spaces(page.find('span', class_='govuk-error-message').text) == 'Error: Select at least one option'
     assert not redis.delete_cache_keys_by_pattern.called