Crate monocoque 

Monocoque

A high-performance, multi-protocol messaging runtime built on io_uring.

Architecture

Monocoque is structured as a messaging kernel with clean layering:

• monocoque-core: Lock-free allocators, io_uring proactor, SPSC queues
• Protocol crates: Pure state machines (sans-IO)
• monocoque: Public API surface (this crate)

Protocols (opt-in via features)

Each protocol is gated behind a feature flag to avoid loading unused code:

• zmq - ZeroMQ (ZMTP 3.x) implementation

[dependencies]
monocoque-rs = { version = "0.1", features = ["zmq"] }

Quick Start

ZeroMQ DEALER Socket (Client)

use monocoque::zmq::prelude::*;

// Connect to a ZeroMQ peer
let mut socket = DealerSocket::connect("127.0.0.1:5555").await?;

// Send a multipart message
socket.send(vec![b"Hello".to_vec().into(), b"World".to_vec().into()]).await?;

// Receive a reply
if let Ok(Some(msg)) = socket.recv().await {
    println!("Received: {:?}", msg);
}

ZeroMQ ROUTER Socket (Server)

use monocoque::zmq::prelude::*;

// Bind and accept first connection
let (listener, mut socket) = RouterSocket::bind("127.0.0.1:5555").await?;

// Echo server
while let Ok(Some(msg)) = socket.recv().await {
    socket.send(msg).await?;
}

Performance

• Zero-copy: Uses bytes::Bytes for refcounted message buffers
• io_uring: Native Linux async I/O (via compio)
• Lock-free: SPSC queues, no shared mutable state in hot paths
• Sans-IO: Protocol logic is pure, testable, and runtime-agnostic

Safety

• unsafe code is isolated to monocoque-core/src/alloc/ (slab allocator)
• All protocol and routing layers are 100% safe Rust
• Formal invariants documented in docs/blueprints/06-safety-model-and-unsafe-audit.md

Structs

Bytes

A cheaply cloneable and sliceable chunk of contiguous memory.

ReconnectState

Reconnection state tracker for managing connection attempts and backoff.

SocketOptions

Socket configuration options.

Enums

ReconnectError

Error type for reconnection operations.

SocketType

ZeroMQ socket types.