Crate skiff_rs 

skiff

An embedded Raft consensus library backed by sled. Skiff lets you embed a replicated key-value store directly in your application without running a separate consensus service.

Architecture

Each participating process runs a Skiff node. Nodes elect a leader among themselves using the Raft protocol. All writes are routed to the leader, replicated to a majority of followers, and only acknowledged once they are durably committed. Followers automatically forward client requests to the current leader, so callers can connect to any node.

Persistent state (Raft hard state, the log, and applied key-value data) is stored in a sled embedded database. A node that restarts will recover its identity and log from disk and re-join the cluster without any manual intervention.

Quick start

use std::net::Ipv4Addr;
use skiff_rs::{Builder, Client};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Build and start a single-node cluster.
    let node = Builder::new()
        .set_dir("/tmp/my-skiff-node")
        .bind("127.0.0.1".parse()?)
        .build()?;

    let node_ref = node.clone();
    tokio::spawn(async move { node_ref.start().await });

    // Block until a leader is elected before connecting a client.
    node.wait_for_leader(std::time::Duration::from_secs(2)).await?;

    // Connect a client and perform some operations.
    let mut client = Client::new(vec!["127.0.0.1".parse()?]);
    client.connect().await?;

    client.insert("greeting", "hello world").await?;
    let value: Option<String> = client.get("greeting").await?;
    println!("{:?}", value);

    Ok(())
}

Multi-node cluster

Pass the addresses of existing cluster members to Builder::join_cluster when constructing additional nodes. The new node will contact one of its peers and register itself via the Raft add_server RPC.

use skiff_rs::Builder;

// Node 1 – sole member of a brand-new cluster.
let node1 = Builder::new()
    .set_dir("/tmp/node1")
    .bind("127.0.0.1".parse()?)
    .build()?;

// Node 2 – joins the cluster seeded by node 1.
let node2 = Builder::new()
    .set_dir("/tmp/node2")
    .bind("127.0.0.2".parse()?)
    .join_cluster(vec!["127.0.0.1".parse()?])
    .build()?;

Structs

Builder

Builder for constructing a Skiff node.

Client

A client for interacting with a skiff cluster.

Skiff

A single node in a skiff cluster.

Subscriber

A streaming receiver for key-value change notifications.

Enums

ElectionState

The current role of a node in the Raft protocol.

Error

All errors that can be returned by skiff.