allow specifying more than one redis server URI in the REDIS_URI env var (#3368)

# What this PR does

Modifies the Django `settings/base.py` such that `REDIS_URI` can now be
a comma (or semicolon) separated list of URIs. From [Django
docs](https://docs.djangoproject.com/en/4.2/topics/cache/#:~:text=If%20you%20have%20multiple%20Redis%20servers%20set%20up%20in%20the%20replication%20mode%2C%20you%20can%20specify%20the%20servers%20either%20as%20a%20semicolon%20or%20comma%20delimited%20string%2C%20or%20as%20a%20list):

> If you have multiple Redis servers set up in the replication mode, you
can specify the servers either as a semicolon or comma delimited string,
or as a list. While using multiple servers, write operations are
performed on the first server (leader). Read operations are performed on
the other servers (replicas) chosen at random:
> ```python3
> CACHES = {
>     "default": {
>         "BACKEND": "django.core.cache.backends.redis.RedisCache",
>         "LOCATION": [
>             "redis://127.0.0.1:6379",  # leader
>             "redis://127.0.0.1:6378",  # read-replica 1
>             "redis://127.0.0.1:6377",  # read-replica 2
>         ],
>     }
> }
> ```

## Checklist

- [ ] Unit, integration, and e2e (if applicable) tests updated (N/A)
- [x] Documentation added (or `pr:no public docs` PR label added if not
required)
- [x] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)

CHANGELOG.md

@@ -7,17 +7,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+
+- Populate `users` field of the public Shift GET API with `rolling_users` from the type override created from web UI([#3303](https://github.com/grafana/oncall/pull/3303))
+- Do not retry to update slack user group on every API error ([#3363](https://github.com/grafana/oncall/pull/3363))
+- Allow specifying a comma-separated list of redis-servers to the `REDIS_URI` engine environment variable by @joeyorlando
+  ([#3368](https://github.com/grafana/oncall/pull/3368))
+
 ### Fixed
 
 - Fixed recurrency limit issue in the Rotation Modal ([#3358](https://github.com/grafana/oncall/pull/3358))
 - Added dragging boundary constraints for Rotation Modal and show scroll for the users list ([#3365](https://github.com/grafana/oncall/pull/3365))
 - Delete direct paging integration on team delete by @vadimkerr ([#3367](https://github.com/grafana/oncall/pull/3367))
 
-### Added
-
-- Populate `users` field of the public Shift GET API with `rolling_users` from the type override created from web UI([#3303](https://github.com/grafana/oncall/pull/3303))
-- Do not retry to update slack user group on every API error ([#3363](https://github.com/grafana/oncall/pull/3363))
-
 ## v1.3.58 (2023-11-14)
 
 ### Added

engine/apps/api/tests/test_openapi_schema.py

@@ -1,13 +1,14 @@
 import pytest
 import yaml
+from django.test import override_settings
 from django.urls import reverse
 from rest_framework import status
 from rest_framework.test import APIClient
 
 
 @pytest.mark.django_db
+@override_settings(DRF_SPECTACULAR_ENABLED=True)
 def test_fetching_the_openapi_schema_works(settings, reload_urls):
-    settings.DRF_SPECTACULAR_ENABLED = True
     reload_urls()
 
     client = APIClient()

engine/settings/base.py

@@ -220,9 +220,7 @@ if REDIS_USE_SSL:
 CACHES = {
     "default": {
         "BACKEND": "redis_cache.RedisCache",
-        "LOCATION": [
-            REDIS_URI,
-        ],
+        "LOCATION": REDIS_URI,
         "OPTIONS": {
             "DB": REDIS_DATABASE,
             "PARSER_CLASS": "redis.connection.HiredisParser",