scylladb/scylla-rust-driver

ScyllaDB Rust Driver

This is a client-side driver for ScyllaDB written in pure Rust with a fully async API using Tokio. Although optimized for ScyllaDB, the driver is also compatible with Apache Cassandra®.

Getting Started

The documentation book is a good place to get started. Another useful resource is the Rust and ScyllaDB lesson on Scylla University.

Examples

use futures::TryStreamExt;

let uri = "127.0.0.1:9042";

let session: Session = SessionBuilder::new().known_node(uri).build().await?;

let query_pager = session.query_iter("SELECT a, b, c FROM ks.t", &[]).await?;
let mut stream = query_pager.rows_stream::<(i32, i32, String)>()?;
while let Some((a, b, c)) = stream.try_next().await? {
    println!("a, b, c: {}, {}, {}", a, b, c);
}

Please see the full example program for more information. You can also run the example as follows if you have a ScyllaDB server running:

SCYLLA_URI="127.0.0.1:9042" cargo run --example basic

All examples are available in the examples directory

Features and Roadmap

The driver supports the following:

• Asynchronous API
• Type-safe serialization and deserialization
• Zero-copy deserialization
• Derive macros for user struct serialization and deserialization
• Token-aware routing
• Shard-aware and Tablet-aware routing (specific to ScyllaDB)
• Prepared, unprepared and batch statements
• Query paging - both transparent and manual
• CachingSession that transparently prepares statements
• CQL binary protocol version 4
• Configurable policies:
  • Load balancing
  • Retry
  • Speculative execution
  • and other (timestamp generation, address translation, host filtering)
• Execution profiles
• Driver-side metrics, and query execution history
• TLS. Both OpenSSL and Rustls are supported
• Compression (LZ4 and Snappy algorithms)
• Authentication
• Cluster metadata access
• CQL tracing

For planned future improvements, see our Milestones.

Feature flags

The driver has several optional features that can be enabled or disabled in Cargo.toml. Refer to scylla/Cargo.toml for the list of available features and their descriptions.

Getting Help

We invite you to discuss any issues and ask questions on the ScyllaDB Forum and the #rust-driver channel on ScyllaDB Slack.

Version support

The driver is considered production ready, hence its version is not 0.x. We do however acknowledge that the API will surely need some breaking changes in the future, which means it is not our goal to stay on 1.x forever - we will release new major version in the future.

The API stability guarantee we provide is that we won't release new major versions very often. In case of 2.0, it won't be released earlier than 9 months after release 1.0. For further major versions this duration may be increased.

After new major version is released, the previous major version will still receive bugfixes for some time (exact time is yet to be determined), but new features will only be developed for the latest major version.

Supported Rust Versions

Our driver's minimum supported Rust version (MSRV) is 1.88.0. Changes to MSRV can only happen in major and minor releases, but not in patch releases. We will not bump MSRV to a Rust version that was released less than 6 months ago.

Reference Documentation

• CQL binary protocol specification version 4

Other Drivers

• cdrs-tokio: Apache Cassandra driver written in pure Rust.
• cassandra-rs: Rust wrappers for the DataStax C++ driver for Apache Cassandra.

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.