Crate clocksync 

Fault-tolerant clock synchronization using Marzullo’s algorithm with nanosecond-precision Nulid timestamps.

This crate provides a decentralized clock consensus mechanism based on Marzullo’s algorithm, which finds the smallest interval consistent with the majority of time sources. All time values are in nanoseconds and the Nulid type is the core data currency throughout.

Usage

Implement ClockSource to define how your application probes remote endpoints. Each probe returns a ProbeResponse containing the peer’s Nulid and round-trip timing. The crate converts this into nanosecond-precision Sample bounds and runs Marzullo’s algorithm to produce a consensus Interval.

use clocksync::{ClockSource, ProbeResponse, consensus};
use nulid::Nulid;
use std::time::Instant;

struct MyClient;

impl ClockSource for MyClient {
    type Error = std::io::Error;

    async fn probe(&self, address: &str) -> Result<ProbeResponse, Self::Error> {
        let start = Instant::now();
        // ... send request to `address`, receive peer's Nulid ...
        let rtt = start.elapsed().as_nanos();
        let peer_id: Nulid = todo!("parse from response");
        Ok(ProbeResponse::new(peer_id, rtt, 0))
    }
}

let source = MyClient;
let addrs = vec!["10.0.0.1:8080", "10.0.0.2:8080", "10.0.0.3:8080"];
let interval = consensus(&addrs, &source).await.expect("consensus found");

// Generate a NULID from consensus time
let id = interval.nulid();

Or use marzullo directly if you already have samples:

use clocksync::{Sample, marzullo};
use nulid::Nulid;

let id = Nulid::from_nanos(1_000_000_000, 1);
let samples = vec![
    Sample::new(100, 110, id, "peer1"),
    Sample::new(105, 115, id, "peer2"),
    Sample::new(108, 118, id, "peer3"),
];

let interval = marzullo(&samples).expect("consensus found");
assert_eq!(interval.lower(), 108);
assert_eq!(interval.upper(), 110);

// Generate a NULID at the consensus midpoint
let consensus_id = interval.nulid();

Structs

Interval

The consensus time interval produced by Marzullo’s algorithm.

ProbeResponse

Response from probing a remote time source.

Sample

A clock sample representing an interval of possible true time in nanoseconds.

Traits

ClockSource

Trait for probing remote endpoints to obtain clock readings.

Functions

consensus

Probe all addresses via source and compute a consensus interval.

marzullo

Apply Marzullo’s algorithm to a set of samples.