redis4cats

Redis client built on top of Cats Effect, Fs2 and the async Java client Lettuce.

Quick Start

import cats.effect.*
import cats.implicits.*
import dev.profunktor.redis4cats.Redis
import dev.profunktor.redis4cats.effect.Log.Stdout.given

object QuickStart extends IOApp.Simple:

  val run: IO[Unit] =
    Redis[IO].utf8("redis://localhost").use: redis =>
      for
        _ <- redis.set("foo", "123")
        x <- redis.get("foo")
        _ <- redis.setNx("foo", "should not happen")
        y <- redis.get("foo")
        _ <- IO(assert(x === y))
      yield ()

The API is quite stable and heavily used in production. However, binary compatibility is not guaranteed across versions for now.

If you like it, give it a ⭐ ! If you think we could do better, please let us know!

Versions

The 1.x.x series is built on Cats Effect 3 whereas the 0.x.x series is built on Cats Effect 2.

redis4cats is a thin wrapper over the async Java client Lettuce, so each series tracks a particular Lettuce major version:

redis4cats	Lettuce	Cats Effect
3.x	7.x	3.x
2.x	6.x (currently 6.8.x)	3.x
1.x	6.x (6.1.x–6.5.x)	3.x
0.x	5.3.x then 6.0.x	2.x

Dependencies

Add this to your build.sbt for the Effects API (depends on cats-effect):

libraryDependencies += "dev.profunktor" %% "redis4cats-effects" % Version

Add this for the Streams API (depends on fs2 and cats-effect):

libraryDependencies += "dev.profunktor" %% "redis4cats-streams" % Version

Log4cats support

redis4cats needs a logger for internal use and provides instances for log4cats. It is the recommended logging library:

libraryDependencies += "dev.profunktor" %% "redis4cats-log4cats" % Version

Running the tests locally

Start both a single Redis node and a cluster using docker-compose:

> docker-compose up
> sbt +test

If you are trying to run cluster mode tests on macOS you might receive host not found errors. As a workaround add new environment variable in docker-compose.yml for RedisCluster: IP=0.0.0.0

The environment section should look like this:

    environment:
      - INITIAL_PORT=30001
      - DEBUG=false
      - IP=0.0.0.0

Code of Conduct

See the Code of Conduct

Contribution Guidelines

This project tracks Redis 8 For the Valkey fork please see Valkey4Cats

LICENSE

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this project except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.