mm1

An Erlang-style actor runtime for Rust.

mm1 gives you lightweight actors that communicate by asynchronous message passing, with Erlang/OTP-inspired building blocks: process links and monitors, trap_exit-style supervision, supervisors, a gen_server-like server behaviour, timers, a name service, and optional multi-node messaging.

Status: pre-1.0 (0.7.x). The API still moves between minor versions. See CHANGELOG.md.

Concepts

• Actor — an async function that receives an exclusive reference to a context and interacts with the system only through traits on that context (send/receive, spawn, link, watch, bind, …). The concrete context type stays opaque to the actor.
• Message — any type marked with #[message]. Addresses are opaque, IPv6-like values; a subnet is an address plus a net-mask.
• Supervision — link/monitor signals plus uniform (many children of one kind) and mixed (a fixed set of heterogeneous children) supervisors.

Example: defining and matching messages

use std::time::Duration;

use mm1::address::Address;
use mm1::proto::message;

// `#[message]` derives serde and marks the type as sendable between actors.
// The crate that uses it must depend on `serde` directly.
#[message]
struct Ping {
    reply_to: Address,
    seq:      u64,
}

#[message]
struct Pong {
    seq: u64,
}

Inside an actor you receive an Envelope and match on it with dispatch!:

use mm1::core::envelope::dispatch;

loop {
    let envelope = ctx.recv().await?;
    dispatch!(match envelope {
        Ping { reply_to, seq } => {
            ctx.tell(reply_to, Pong { seq }).await.ok();
        }
        // `dispatch!` requires a catch-all today, otherwise an unexpected
        // message panics the actor.
        other @ _ => {
            // handle or ignore
        }
    });
}

For complete, runnable programs — starting a node, wiring config, supervision, and multi-node messaging — see the crates under tests/ (for example tests/mm1-node-tests and the tests/mm1-multinode-tests/examples directory).

Features

The umbrella mm1 crate re-exports the subsystem crates behind feature flags.

Default: ask, runtime, server, sup, timer, multinode.

Minimum supported Rust version

mm1 builds on Rust 1.91 and later. Bumping the MSRV is treated as a routine change, not a breaking one, while the crate is pre-1.0.

License

MIT. See LICENSE.