reactive-messaging

Provides Stream-based reactive client/server communications focused on high performance.

Still in beta, the distinct features of this library are:

• ease of logic decoupling by using reactive Streams for the client / server logic;
• protocol modeling through Rust's powerful enums;
• 3 serialization strategies: textual (new-line separated), fixed size binary, and variable size binary, with different compromises between debugging, integration, speed, and flexibility;
• custom serializers / deserializers allowed, with defaults being ron (for textual), mmap (for fixed size binary), and rkyv (for variable size binary);
• serdes may be selected at runtime, sharing the same logic (with some exceptions in rkyv);
• simple API for creating the client and server instances;
• yet allowing advanced usages: composite protocols with different models between "states" and state transition logic;
• when working with composite protocols, you are free to upgrade the serializers -- like authenticating with ron and message passing with mmap;
• the network loops for both client & server are fully optimized and generics is fully used, providing yet more optimizations;
• compile-time (generics & const, yet powerful) configurations, to achieve the most performance possible;
• full support for retrying strategies, using zero-cost abstractions provided by keen-retry;

Taste it

Take a look at the ping-pong game in example/, which shows some nice patterns on how to use this library:

• How the ping-pong game logic is shared among the client and server;
• How the protocol is modeled (we use the composite-protocol pattern there);
• How to work with server-side sessions;
• How decoupled and testable those pieces are;
• How straight-forward it is to create flexible server & client applications once the processors are complete.

beta status

The API has been stabilized -- new features yet to be added for v1.0:

• allow reactive processors to produce all combinations of fallible/non-fallible & futures/non-futures for; responsive & unresponsive logic processors (currently, only Streams of non-fallible & non-future items are allowed);
• unified tests for all the 3 default serdes;
• better docs;
• complete the companion book.

Production-ready?

This crate is currently being used successfully in production for both Textual (ron) and Fixed Binary (mmap), supporting 380 msgs/s per instance, with 0.5% CPU overhead on a GCE e2-micro instance -- please check the "Flood Example" to measure base system resources needed for an arbitrary msgs/s load.

We will formally claim "Production ready" once the book is ready and more tests and examples are made.