Flask-Redis

Flask-Redis is an extension for Flask that adds support for Redis to your application. It aims to simplify manage multi Redis databases with Flask.

Installing

Install and update using pip:

pip install flask-redis-ext

A Simple Example

from flask import Flask
from flask-redis import Redis

redis = Redis()
app = Flask(__name__)

app.config["REDIS_PREFIX"] = "EG:"
app.config["REDIS_URL"] = "redis://:password@host:port/db"
app.config["REDIS_DECODE_RESPONSES"] = True
redis.init_app(app)

redis.get("test")

Multiple Databases

from flask import Flask
from flask_redis import Redis

redis = Redis()
app = Flask(__name__)

app.config["REDIS_BINDS"] = {
    "default": {
        "REDIS_URL": "redis://:password@host:port/db",
    },
    "DB12": {
        "REDIS_PREFIX": "EG12:",
        "REDIS_URL": "redis://:password@host:port/db",
    },
    "DB13": {
        "REDIS_PREFIX": "EG13:",
        "REDIS_URL": "redis://:password@host:port/db",
    }
}
redis.init_app(app)

# use default database
redis.set("key1", "value1)
# use db12
redis["DB12"].set("key1", "value1")
# use getter
redis.DB12.set("key1", "value1)

Support Parameter

Parameter	Explain	Example
REDIS_PREFIX	storage key prefix	app.config["REDIS_PREFIX"] = "EG:"
REDIS_BINDS	bind multi databases	--
REDIS_URL	redis url	redis://xx
REDIS_DEFAULT_BIND_KEY	default redis bind key	app.config["REDIS_DEFAULT_BIND_KEY"] = "default"
REDIS_CONNECTION_POOL	custom connection pool	app.config["REDIS_CONNECTION_POOL"] = ConnectionPool()

Redis Parameter

We support all of the origin redis init parameter which should be started with "REDIS_". socket_timeout should be config as REDIS_SOCKET_TIMEOUT. encoding should be config as REDIS_ENCODING. All other parameters follow the same rules.

Redis Prefix

Flask-Redis support auto add key prefix for all of the DataAccessCommands.

For example, if you use redis.set("k", "v") to store value at k and redis prefix is EG:, the really key in redis storage is "EG:k".

Redis prefix is a globally effective configuration parameter. if you don't want to add prefix for special key, you can add - character to ignore prefix. e.g. redis.set("-k", "v") which will store really 'k' as key in redis.

Decorator cached

Flask-Redis support cached decorator to cache function result.

@redis.cached(key="{k1}:{k2}:{k3}", timeout=10)
def cache_func(sf, k1, k2=1, **kwargs):
    return sf.v1

Cluster Mode

Flask-Redis support redis cluster mode. There are multiple ways in which a cluster instance can be created:

Specially, Flask-Redis don't support multi cluster, therefore REDIS_BINDS is invalid for this mode.

• Using the Redis URL specification:

from flask import Flask
from flask_redis import RedisCluster

app = Flask(__name__)
app.config["REDIS_DECODE_RESPONSES"] = True
app.config["REDIS_PREFIX"] = "CLU:"
app.config["REDIS_URL"] = "redis://:@127.0.0.1:7001/0"

redis = RedisCluster()
redis.init_app(app)

print(redis.get_nodes())
redis.set("K", "V")

• Using host and port arguments:

from flask import Flask
from flask_redis import RedisCluster

app = Flask(__name__)
app.config["REDIS_DECODE_RESPONSES"] = True
app.config["REDIS_PREFIX"] = "CLU:"
app.config["REDIS_HOST"] = "127.0.0.1"
app.config["REDIS_PORT"] = "7001"

redis = RedisCluster()
redis.init_app(app)

print("redis.get_nodes()")
redis.set("K", "V")

Sentinel Mode

Flask-Redis support sentinel mode. You can use a Sentinel connection to discover the master and slaves network address. You can also create redis client connections from a sentinel instance.

from flask import Flask
from flask_redis import Sentinel

app = Flask(__name__)

app.config["REDIS_PREFIX"] = "SEN:"
app.config["REDIS_SENTINELS"] = [("192.168.1.189", 18001)]
app.config["REDIS_SENTINEL_KWARGS"] = {
    "socket_timeout": 0.1
}
app.config["REDIS_CONNECTION_KWARGS"] = {
    "decode_responses": True
}

rds = Sentinel()
rds.init_app(app)

print(rds.discover_master("mymaster"))
print(rds.discover_slaves("mymaster"))

master = rds.master_for("mymaster")
slave = rds.slave_for("mymaster")

master.set("k", "v")
slave.get("k")

Sentinel mode is different from other simple and Cluster mode. in this mode, you should use REDIS_SENTINELS parameter to config connection info. You will get details about sentinel mode parameter at below:

Parameter	Explain	Example
REDIS_SENTINELS	sentinel connections	app.config["REDIS_SENTINELS"] = [("192.168.1.189", 18001)]
REDIS_SENTINEL_KWARGS	sentinel kwargs for Sentinel	app.config["REDIS_SENTINEL_KWARGS"] = {"socket_timeout": 0.1}
REDIS_CONNECTION_KWARGS	redis connection kwargs	app.config["REDIS_CONNECTION_KWARGS"] = {"decode_responses": True}

Links

• Release: https://pypi.org/project/flask-redis-ext/
• Code: https://github.com/Eastwu5788/Flask-Redis
• Issue tracker: https://github.com/Eastwu5788/Flask-Redis/issues
• Test status: https://coveralls.io/github/Eastwu5788/Flask-Redis