From fade83a61edf6e4ea67ce8e0d71bf2573685810b Mon Sep 17 00:00:00 2001
From: Mel <97147377+MelissaAutumn@users.noreply.github.com>
Date: Wed, 22 May 2024 13:13:06 -0700
Subject: [PATCH] if $REDIS_USE_CLUSTER = True then connect to a redis cluster
 (#417)

---
 backend/.env.example                          |  2 ++
 .../src/appointment/controller/calendar.py    |  7 ++---
 .../src/appointment/dependencies/database.py  | 30 ++++++++++++++-----
 backend/src/appointment/routes/api.py         |  4 +--
 4 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/backend/.env.example b/backend/.env.example
index 541c15619..0949ad5d7 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -99,6 +99,8 @@ REDIS_DB=0
 # No value = Python None
 REDIS_PASSWORD
 REDIS_USE_SSL=False
+# Connect to a redis cluster instead of a single instance
+REDIS_USE_CLUSTER=False
 
 # In minutes, the time a cached remote event will expire at.
 REDIS_EVENT_EXPIRE_TIME=15
diff --git a/backend/src/appointment/controller/calendar.py b/backend/src/appointment/controller/calendar.py
index 4b981ed64..77ac7a451 100644
--- a/backend/src/appointment/controller/calendar.py
+++ b/backend/src/appointment/controller/calendar.py
@@ -4,13 +4,12 @@
 """
 import json
 import logging
-import uuid
 import zoneinfo
 import os
 
 import caldav.lib.error
 import requests
-from redis import Redis
+from redis import Redis, RedisCluster
 from caldav import DAVClient
 from fastapi import BackgroundTasks
 from google.oauth2.credentials import Credentials
@@ -29,11 +28,11 @@
 
 
 class BaseConnector:
-    redis_instance: Redis | None
+    redis_instance: Redis | RedisCluster | None
     subscriber_id: int
     calendar_id: int
 
-    def __init__(self, subscriber_id: int, calendar_id: int | None, redis_instance: Redis | None = None):
+    def __init__(self, subscriber_id: int, calendar_id: int | None, redis_instance: Redis | RedisCluster | None = None):
         self.redis_instance = redis_instance
         self.subscriber_id = subscriber_id
         self.calendar_id = calendar_id
diff --git a/backend/src/appointment/dependencies/database.py b/backend/src/appointment/dependencies/database.py
index 6f6f435dc..67d5ecc62 100644
--- a/backend/src/appointment/dependencies/database.py
+++ b/backend/src/appointment/dependencies/database.py
@@ -1,6 +1,6 @@
 import os
 
-from redis import Redis
+from redis import Redis, RedisCluster
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 
@@ -29,17 +29,33 @@ def get_db():
         db.close()
 
 
-def get_redis() -> Redis | None:
+def get_redis() -> Redis | RedisCluster | None:
     """Retrieves a redis instance or None if redis isn't available."""
     # TODO: Create pool and simply grab instance?
     if os.getenv('REDIS_URL') is None:
         return None
 
+    host = os.getenv('REDIS_URL')
+    port = int(os.getenv('REDIS_PORT'))
+    db = os.getenv('REDIS_DB')
+    password = os.getenv('REDIS_PASSWORD')
+    ssl = os.getenv('REDIS_USE_SSL')
+
+    if os.getenv('REDIS_USE_CLUSTER'):
+        return RedisCluster(
+            host=host,
+            port=port,
+            db=db,
+            password=password,
+            ssl=ssl,
+            decode_responses=True,
+        )
+
     return Redis(
-        host=os.getenv('REDIS_URL'),
-        port=os.getenv('REDIS_PORT'),
-        db=os.getenv('REDIS_DB'),
-        password=os.getenv('REDIS_PASSWORD'),
-        ssl=os.getenv('REDIS_USE_SSL'),
+        host=host,
+        port=port,
+        db=db,
+        password=password,
+        ssl=ssl,
         decode_responses=True,
     )
diff --git a/backend/src/appointment/routes/api.py b/backend/src/appointment/routes/api.py
index 0e00a7351..8db06f425 100644
--- a/backend/src/appointment/routes/api.py
+++ b/backend/src/appointment/routes/api.py
@@ -5,7 +5,7 @@
 
 import requests.exceptions
 import validators
-from redis import Redis
+from redis import Redis, RedisCluster
 from requests import HTTPError
 from sentry_sdk import capture_exception
 from sqlalchemy.exc import SQLAlchemyError
@@ -316,7 +316,7 @@ def read_remote_events(
     db: Session = Depends(get_db),
     google_client: GoogleClient = Depends(get_google_client),
     subscriber: Subscriber = Depends(get_subscriber),
-    redis_instance: Redis | None = Depends(get_redis),
+    redis_instance: Redis | RedisCluster | None = Depends(get_redis),
 ):
     """endpoint to get events in a given date range from a remote calendar"""
     db_calendar = repo.calendar.get(db, calendar_id=id)