redis-rs

Redis-rs is a high level Rust library for Redis. It provides convenient access to all Redis functionality through a very flexible but low-level API. It uses a customizable type conversion trait so that any operation can return results in just the type you are expecting. This makes for a very pleasant development experience.

The crate is called redis and you can depend on it via cargo:

[dependencies]
redis = "0.27.6"

Documentation on the library can be found at docs.rs/redis.

Basic Operation

To open a connection you need to create a client and then to fetch a connection from it.

Many commands are implemented through the Commands trait but manual command creation is also possible.

use redis::Commands;

fn fetch_an_integer() -> redis::RedisResult<isize> {
    // connect to redis
    let client = redis::Client::open("redis://127.0.0.1/")?;
    let mut con = client.get_connection()?;
    // throw away the result, just make sure it does not fail
    let _: () = con.set("my_key", 42)?;
    // read back the key and return it.  Because the return value
    // from the function is a result for integer this will automatically
    // convert into one.
    con.get("my_key")
}

Variables are converted to and from the Redis format for a wide variety of types (String, num types, tuples, Vec<u8>). If you want to use it with your own types, you can implement the FromRedisValue and ToRedisArgs traits, or derive it with the redis-macros crate.

Async support

To enable asynchronous clients, enable the relevant feature in your Cargo.toml, tokio-comp for tokio users or async-std-comp for async-std users.

# if you use tokio
redis = { version = "0.27.6", features = ["tokio-comp"] }

# if you use async-std
redis = { version = "0.27.6", features = ["async-std-comp"] }

Connection Pooling

When using a sync connection, it is recommended to use a connection pool in order to handle disconnects or multi-threaded usage. This can be done using the r2d2 feature.

redis = { version = "0.27.6", features = ["r2d2"] }

For async connections, connection pooling isn't necessary, unless blocking commands are used. The MultiplexedConnection is cloneable and can be used safely from multiple threads, so a single connection can be easily reused. For automatic reconnections consider using ConnectionManager with the connection-manager feature. Async cluster connections also don't require pooling and are thread-safe and reusable.

Multiplexing won't help if blocking commands are used since the server won't handle commands from blocked connections until the connection is unblocked. If you want to be able to handle non-blocking commands concurrently with blocking commands, you should send the blocking commands on another connection.

TLS Support

To enable TLS support, you need to use the relevant feature entry in your Cargo.toml. Currently, native-tls and rustls are supported.

To use native-tls:

redis = { version = "0.27.6", features = ["tls-native-tls"] }

# if you use tokio
redis = { version = "0.27.6", features = ["tokio-native-tls-comp"] }

# if you use async-std
redis = { version = "0.27.6", features = ["async-std-native-tls-comp"] }

To use rustls:

redis = { version = "0.27.6", features = ["tls-rustls"] }

# if you use tokio
redis = { version = "0.27.6", features = ["tokio-rustls-comp"] }

# if you use async-std
redis = { version = "0.27.6", features = ["async-std-rustls-comp"] }

Add rustls to dependencies

rustls = { version = "0.23", features = ["ring"] }

And then, before creating a connection, ensure that you install a crypto provider. For example:

    rustls::crypto::ring::default_provider()
        .install_default()
        .expect("Failed to install rustls crypto provider");

With rustls, you can add the following feature flags on top of other feature flags to enable additional features:

• tls-rustls-insecure: Allow insecure TLS connections
• tls-rustls-webpki-roots: Use webpki-roots (Mozilla's root certificates) instead of native root certificates

then you should be able to connect to a redis instance using the rediss:// URL scheme:

let client = redis::Client::open("rediss://127.0.0.1/")?;

To enable insecure mode, append #insecure at the end of the URL:

let client = redis::Client::open("rediss://127.0.0.1/#insecure")?;

Deprecation Notice: If you were using the tls or async-std-tls-comp features, please use the tls-native-tls or async-std-native-tls-comp features respectively.

Cluster Support

Support for Redis Cluster can be enabled by enabling the cluster feature in your Cargo.toml:

redis = { version = "0.27.6", features = [ "cluster"] }

Then you can simply use the ClusterClient, which accepts a list of available nodes. Note that only one node in the cluster needs to be specified when instantiating the client, though you can specify multiple.

use redis::cluster::ClusterClient;
use redis::Commands;

fn fetch_an_integer() -> String {
    let nodes = vec!["redis://127.0.0.1/"];
    let client = ClusterClient::new(nodes).unwrap();
    let mut connection = client.get_connection().unwrap();
    let _: () = connection.set("test", "test_data").unwrap();
    let rv: String = connection.get("test").unwrap();
    return rv;
}

Async Redis Cluster support can be enabled by enabling the cluster-async feature, along with your preferred async runtime, e.g.:

redis = { version = "0.27.6", features = [ "cluster-async", "tokio-std-comp" ] }

use redis::cluster::ClusterClient;
use redis::AsyncCommands;

async fn fetch_an_integer() -> String {
    let nodes = vec!["redis://127.0.0.1/"];
    let client = ClusterClient::new(nodes).unwrap();
    let mut connection = client.get_async_connection().await.unwrap();
    let _: () = connection.set("test", "test_data").await.unwrap();
    let rv: String = connection.get("test").await.unwrap();
    return rv;
}

JSON Support

Support for the RedisJSON Module can be enabled by specifying "json" as a feature in your Cargo.toml.

redis = { version = "0.27.6", features = ["json"] }

Then you can simply import the JsonCommands trait which will add the json commands to all Redis Connections (not to be confused with just Commands which only adds the default commands)

use redis::Client;
use redis::JsonCommands;
use redis::RedisResult;
use redis::ToRedisArgs;

// Result returns Ok(true) if the value was set
// Result returns Err(e) if there was an error with the server itself OR serde_json was unable to serialize the boolean
fn set_json_bool<P: ToRedisArgs>(key: P, path: P, b: bool) -> RedisResult<bool> {
    let client = Client::open("redis://127.0.0.1").unwrap();
    let connection = client.get_connection().unwrap();

    // runs `JSON.SET {key} {path} {b}`
    connection.json_set(key, path, b)?
}

To parse the results, you'll need to use serde_json (or some other json lib) to deserialize the results from the bytes. It will always be a Vec, if no results were found at the path it'll be an empty Vec. If you want to handle deserialization and Vec unwrapping automatically, you can use the Json wrapper from the redis-macros crate.

Development

To test redis you're going to need to be able to test with the Redis Modules, to do this you must set the following environment variable before running the test script

• REDIS_RS_REDIS_JSON_PATH = The absolute path to the RedisJSON module (Either librejson.so for Linux or librejson.dylib for MacOS).

• Please refer to this link to access the RedisJSON module:

If you want to develop on the library there are a few commands provided by the makefile:

To build:

$ make

To test:

Note: make test requires cargo-nextest installed, to learn more about it please visit homepage of cargo-nextest.

$ make test

To run benchmarks:

$ make bench

To build the docs (require nightly compiler, see rust-lang/rust#43781):

$ make docs

We encourage you to run clippy prior to seeking a merge for your work. The lints can be quite strict. Running this on your own workstation can save you time, since Travis CI will fail any build that doesn't satisfy clippy:

$ cargo clippy --all-features --all --tests --examples -- -D clippy::all -D warnings

To run fuzz tests with afl, first install cargo-afl (cargo install -f afl), then run:

$ make fuzz

If the fuzzer finds a crash, in order to reproduce it, run:

$ cd afl/<target>/
$ cargo run --bin reproduce -- out/crashes/<crashfile>