Add support for Redis Sentinel

.github/workflows/test.yaml

@@ -6,34 +6,9 @@ jobs:
         strategy:
             matrix:
                 python-version: [3.8, 3.9, 3.10, 3.11, 3.12]
-        services:
-            mongodb:
-                image: mongo
-                ports:
-                    - 27017:27017
-            dynamodb:
-                image: amazon/dynamodb-local
-                ports:
-                    - 8000:8000
-
-            postgresql:
-                image: postgres:latest
-                ports:
-                    - 5433:5432
-                env:
-                    POSTGRES_PASSWORD: pwd
-                    POSTGRES_USER: root
-                    POSTGRES_DB: dummy
-                # Set health checks to wait until postgres has started
-                options: >-
-                    --health-cmd pg_isready
-                    --health-interval 10s
-                    --health-timeout 5s
-                    --health-retries 5
         steps:
             - uses: actions/checkout@v4
-            - uses: supercharge/[email protected]
-            - uses: niden/actions-memcached@v7
+            - uses: hoverkraft-tech/[email protected]
             - name: Install testing requirements
               run: pip3 install -r requirements/dev.txt
             - name: Run tests

README.md

@@ -48,7 +48,7 @@ def get():
 
 ## Supported Storage Types
 
--   Redis
+-   Redis (standalone and Sentinel)
 -   Memcached
 -   FileSystem
 -   MongoDB

docker-compose.yml

@@ -41,8 +41,152 @@ services:
     volumes:
       - postgres_data:/var/lib/postgresql/data
 
+  redis-master:
+      image: redis:latest
+      container_name: redis-master
+      command:
+        [
+            "redis-server",
+            "--port",
+            "6380",
+            "--protected-mode",
+            "no"
+        ]
+      network_mode: host
+      volumes:
+          - redis_ha_master_data:/data
+
+
+  redis-slave-1:
+      image: redis:latest
+      container_name: redis-slave-1
+      depends_on:
+          - redis-master
+      command:
+        [
+            "redis-server",
+            "--port",
+            "6381",
+            "--replicaof",
+            "127.0.0.1",
+            "6380",
+            "--protected-mode",
+            "no"
+        ]
+      network_mode: host
+      volumes:
+          - redis_ha_slave_1_data:/data
+
+
+  redis-slave-2:
+      image: redis:latest
+      container_name: redis-slave-2
+      depends_on:
+          - redis-master
+      command:
+        [
+            "redis-server",
+            "--port",
+            "6382",
+            "--replicaof",
+            "127.0.0.1",
+            "6380",
+            "--protected-mode",
+            "no"
+        ]
+      network_mode: host
+      volumes:
+          - redis_ha_slave_2_data:/data
+
+
+  sentinel-1:
+      image: redis:latest
+      container_name: sentinel-1
+      depends_on:
+          - redis-master
+      configs:
+          - source: sentinel
+            target: /data/sentinel.conf
+            mode: 0660
+            uid: "999"
+      command:
+        [
+            "redis-server",
+            "sentinel.conf",
+            "--port",
+            "26379",
+            "--sentinel",
+        ]
+      network_mode: host
+      ports:
+          - "26379:26379"
+      volumes:
+          - redis_ha_sentinel_1_data:/data
+
+
+  sentinel-2:
+      image: redis:latest
+      container_name: sentinel-2
+      depends_on:
+          - redis-master
+      configs:
+          - source: sentinel
+            target: /data/sentinel.conf
+            mode: 0660
+            uid: "999"
+      command:
+        [
+            "redis-server",
+            "sentinel.conf",
+            "--port",
+            "26380",
+            "--sentinel",
+        ]
+      network_mode: host
+      volumes:
+          - redis_ha_sentinel_2_data:/data
+
+
+  sentinel-3:
+      image: redis:latest
+      container_name: sentinel-3
+      depends_on:
+          - redis-master
+      configs:
+          - source: sentinel
+            target: /data/sentinel.conf
+            mode: 0660
+            uid: "999"
+      command:
+        [
+            "redis-server",
+            "sentinel.conf",
+            "--port",
+            "26381",
+            "--sentinel",
+        ]
+      network_mode: host
+      volumes:
+          - redis_ha_sentinel_3_data:/data
+
 volumes:
-  postgres_data:
-  mongo_data:
-  redis_data:
-  dynamodb_data:
+    postgres_data:
+    mongo_data:
+    redis_data:
+    dynamodb_data:
+    redis_ha_master_data:
+    redis_ha_slave_1_data:
+    redis_ha_slave_2_data:
+    redis_ha_sentinel_1_data:
+    redis_ha_sentinel_2_data:
+    redis_ha_sentinel_3_data:
+
+configs:
+    sentinel:
+        content: |
+            bind 0.0.0.0
+            sentinel monitor mymaster 127.0.0.1 6380 2
+            sentinel resolve-hostnames yes
+            sentinel down-after-milliseconds mymaster 5000
+            sentinel failover-timeout mymaster 5000
+            sentinel parallel-syncs mymaster 1

docs/api.rst

@@ -15,6 +15,7 @@ Anything documented here is part of the public API that Flask-Session provides,
    :members: regenerate
 
 .. autoclass:: flask_session.redis.RedisSessionInterface
+.. autoclass:: flask_session.redis.RedisSentinelSessionInterface
 .. autoclass:: flask_session.memcached.MemcachedSessionInterface
 .. autoclass:: flask_session.filesystem.FileSystemSessionInterface
 .. autoclass:: flask_session.cachelib.CacheLibSessionInterface

docs/config_example.rst

@@ -17,6 +17,21 @@ If you do not set ``SESSION_REDIS``, Flask-Session will assume you are developin
 :meth:`redis.Redis` instance for you. It is expected you supply an instance of
 :meth:`redis.Redis` in production.
 
+Similarly, if you use a high-availability setup for Redis using Sentinel you can use the following setup
+
+.. code-block:: python
+
+    from redis import Sentinel
+    app.config['SESSION_TYPE'] = 'redissentinel'
+    app.config['SESSION_REDIS_SENTINEL'] = Sentinel(
+            [("127.0.0.1", 26379), ("127.0.0.1", 26380), ("127.0.0.1", 26381)],
+        )
+
+It is expected that you set ``SESSION_REDIS_SENTINEL`` to your own :meth:`redis.Sentinel` instance.
+The name of the master set is obtained via the config ``SESSION_REDIS_SENTINEL_MASTER_SET`` which defaults to ``mymaster``.
+
+
+
 .. note::
 
     By default, sessions in Flask-Session are permanent with an expiration of 31 days.

docs/config_reference.rst

@@ -13,6 +13,7 @@ These are specific to Flask-Session.
    Specifies which type of session interface to use. Built-in session types:
 
    - **redis**: RedisSessionInterface
+   - **redissentinel**: RedisSentinelSessionInterface
    - **memcached**: MemcachedSessionInterface
    - **filesystem**: FileSystemSessionInterface (Deprecated in 0.7.0, will be removed in 1.0.0 in favor of CacheLibSessionInterface)
    - **cachelib**: CacheLibSessionInterface

src/flask_session/__init__.py

@@ -61,6 +61,9 @@ def _get_interface(self, app):
         # Redis settings
         SESSION_REDIS = config.get("SESSION_REDIS", Defaults.SESSION_REDIS)
 
+        SESSION_REDIS_SENTINEL = config.get("SESSION_REDIS_SENTINEL", Defaults.SESSION_REDIS_SENTINEL)
+        SESSION_REDIS_SENTINEL_MASTER_SET = config.get("SESSION_REDIS_SENTINEL_MASTER_SET", Defaults.SESSION_REDIS_SENTINEL_MASTER_SET)
+
         # Memcached settings
         SESSION_MEMCACHED = config.get("SESSION_MEMCACHED", Defaults.SESSION_MEMCACHED)
 
@@ -144,6 +147,14 @@ def _get_interface(self, app):
                 **common_params,
                 client=SESSION_REDIS,
             )
+        elif SESSION_TYPE == "redissentinel":
+            from .redis import RedisSentinelSessionInterface
+
+            session_interface = RedisSentinelSessionInterface(
+                **common_params,
+                client=SESSION_REDIS_SENTINEL,
+                master=SESSION_REDIS_SENTINEL_MASTER_SET,
+            )
         elif SESSION_TYPE == "memcached":
             from .memcached import MemcachedSessionInterface
 

src/flask_session/defaults.py

@@ -16,6 +16,10 @@ class Defaults:
     # Redis settings
     SESSION_REDIS = None
 
+    # Redis Sentinal settings
+    SESSION_REDIS_SENTINEL = None
+    SESSION_REDIS_SENTINEL_MASTER_SET = "mymaster"
+
     # Memcached settings
     SESSION_MEMCACHED = None
 

src/flask_session/redis/__init__.py

@@ -1 +1,2 @@
 from .redis import RedisSession, RedisSessionInterface  # noqa: F401
+from .redis_sentinel import RedisSentinelSession, RedisSentinelSessionInterface

src/flask_session/redis/redis_sentinel.py

@@ -0,0 +1,57 @@
+from typing import Optional
+
+from flask import Flask
+from redis import Sentinel
+
+from .redis import RedisSessionInterface
+from ..base import ServerSideSession
+from ..defaults import Defaults
+
+
+class RedisSentinelSession(ServerSideSession):
+    pass
+
+
+class RedisSentinelSessionInterface(RedisSessionInterface):
+    """Uses the Redis key-value store deployed in a high availability mode as a session storage. (`redis-py` required)
+
+    :param client: A ``redis.Sentinel`` instance.
+    :param master: The name of the master node.
+    :param key_prefix: A prefix that is added to all storage keys.
+    :param use_signer: Whether to sign the session id cookie or not.
+    :param permanent: Whether to use permanent session or not.
+    :param sid_length: The length of the generated session id in bytes.
+    :param serialization_format: The serialization format to use for the session data.
+    """
+
+    session_class = RedisSentinelSession
+    ttl = True
+
+    def __init__(
+        self,
+        app: Flask,
+        client: Optional[Sentinel] = Defaults.SESSION_REDIS_SENTINEL,
+        master: str = Defaults.SESSION_REDIS_SENTINEL_MASTER_SET,
+        key_prefix: str = Defaults.SESSION_KEY_PREFIX,
+        use_signer: bool = Defaults.SESSION_USE_SIGNER,
+        permanent: bool = Defaults.SESSION_PERMANENT,
+        sid_length: int = Defaults.SESSION_ID_LENGTH,
+        serialization_format: str = Defaults.SESSION_SERIALIZATION_FORMAT,
+    ):
+        if client is None or not isinstance(client, Sentinel):
+            raise TypeError("No valid Sentinel instance provided.")
+        self.sentinel = client
+        self.master = master
+        super().__init__(
+            app, self.client, key_prefix, use_signer, permanent, sid_length, serialization_format
+        )
+        self._client = None
+
+    @property
+    def client(self):
+        return self.sentinel.master_for(self.master)
+
+    @client.setter
+    def client(self, value):
+        # the _client is only needed and the setter only needed for the inheritance to work
+        self._client = value

tests/test_redis.py

@@ -2,8 +2,9 @@
 from contextlib import contextmanager
 
 import flask
-from flask_session.redis import RedisSession
-from redis import Redis
+from flask_session.defaults import Defaults
+from flask_session.redis import RedisSession, RedisSentinelSession
+from redis import Redis, Sentinel
 
 
 class TestRedisSession:
@@ -40,3 +41,46 @@ def test_redis_default(self, app_utils):
                     json.loads(byte_string.decode("utf-8")) if byte_string else {}
                 )
                 assert stored_session.get("value") == "44"
+
+
+class TestRedisSentinelSession:
+    """This requires package: redis"""
+
+    @contextmanager
+    def setup_sentinel(self):
+        self.sentinel = Sentinel(
+            [("127.0.0.1", 26379), ("127.0.0.1", 26380), ("127.0.0.1", 26381)],
+            # sentinel_kwargs={"password": "redispassword"},
+            # socket_timeout=1
+        )
+        self.master: Redis = self.sentinel.master_for(
+            Defaults.SESSION_REDIS_SENTINEL_MASTER_SET
+        )
+        self.master.flushall()
+        yield
+        self.master.flushall()
+
+    def retrieve_stored_session(self, key):
+        master = self.sentinel.master_for(
+            Defaults.SESSION_REDIS_SENTINEL_MASTER_SET
+        )
+        return master.get(key)
+
+    def test_redis_default(self, app_utils):
+        with self.setup_sentinel():
+            app = app_utils.create_app(
+                {"SESSION_TYPE": "redissentinel", "SESSION_REDIS_SENTINEL": self.sentinel}
+            )
+
+            with app.test_request_context():
+                assert isinstance(flask.session, RedisSentinelSession)
+                app_utils.test_session(app)
+
+                # Check if the session is stored in Redis
+                cookie = app_utils.test_session_with_cookie(app)
+                session_id = cookie.split(";")[0].split("=")[1]
+                byte_string = self.retrieve_stored_session(f"session:{session_id}")
+                stored_session = (
+                    json.loads(byte_string.decode("utf-8")) if byte_string else {}
+                )
+                assert stored_session.get("value") == "44"