watermelon

watermelon is an independent and opinionated implementation of the NATS client protocol and the NATS client API for Rust. The goal of the project is to produce a more secure, composable and idiomatic implementation compared to the official one.

Most users of this project will depend on the watermelon crate directly and on watermelon-proto and watermelon-nkeys via the re-exports in watermelon.

Watermelon is divided into multiple crates, all hosted in the same monorepo.

Crate name	Crates.io release	Docs	Description
watermelon			High level actor based NATS Core and NATS Jetstream client implementation
watermelon-mini			Bare bones NATS Core client implementation
watermelon-net			Low-level NATS Core network implementation
watermelon-proto			#[no_std] NATS Core Sans-IO protocol implementation
watermelon-nkeys			Minimal NKeys implementation for NATS client authentication

Philosophy and Design

1. Security by design: this library uses type-safe and checked APIs, such as Subject, to prevent entire classes of errors and security vulnerabilities.
2. Layering and composability: the library is split into layers. You can get a high-level, batteries included implementation via watermelon, or depend directly on the lower-level crates for maximum flexibility.
3. Opinionated, Rusty take: we adapt the Go-style API of nats-server and apply different trade-offs to make NATS feel more Rusty. We sacrifice a bit of performance by enabling server verbose mode, and get better errors in return.
4. Legacy is in the past: we only support nats-server >= 2.10 and avoid legacy versions compatibility code like the STARTTLS-style TLS upgrade path or fallbacks for older JetStream APIs. We also prefer pull consumers over push consumers given the robust flow control, easier compatibility with multi-account environments and stronger permissions handling.
5. Permissive licensing: dual licensed under MIT and APACHE-2.0.

License

Licensed under either of

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

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.