Struct HintStore 

pub struct HintStore { /* private fields */ }

Node-local hint store.

The store is internally synchronised so std::sync::Arc clones share the same per-peer queues. Operations are O(1) with respect to the number of pending hints for the queried peer and O(N) for HintStore::expire_now.

Implementations

impl HintStore

pub fn new(max_bytes: u64) -> Self

Build a new store with the supplied byte cap.

max_bytes of zero means “no cap”; this is intended for tests that drive enqueue/take patterns and never want to exercise the back-pressure branch.

pub fn open<P: AsRef<Path>>( dir: P, max_bytes: u64, ) -> Result<Self, HintStoreOpenError>

Build a durable store backed by per-peer segment files under dir, replaying any segments already present.

On success the in-memory queues are pre-populated with every intact hint found on disk whose wall-clock deadline has not yet passed (re-anchored to the monotonic clock). A torn trailing record in any segment is discarded silently; see the module-level torn-tail documentation. The replayed bytes are counted toward max_bytes, so a store recovered from disk enforces the same combined cap the RAM-only store does.

Errors

• HintStoreOpenError::Dir when dir cannot be created or its entries cannot be listed.
• HintStoreOpenError::Segment when a segment file exists but cannot be opened or read (a torn tail is not an error; an unreadable file is).

Examples

use std::time::Duration;
use dynomite::cluster::hints::HintStore;

let dir = tempfile::tempdir().unwrap();
let store = HintStore::open(dir.path(), 1024).unwrap();
store.enqueue(1, b"hi".to_vec(), Duration::from_secs(60)).unwrap();
drop(store);
let reopened = HintStore::open(dir.path(), 1024).unwrap();
assert_eq!(reopened.len_for(1), 1);

pub fn enqueue( &self, peer_idx: u32, payload: Vec<u8>, ttl: Duration, ) -> Result<(), HintStoreError>

Append a hint for peer_idx. The hint expires at Instant::now() + ttl.

Errors

• HintStoreError::ZeroTtl when ttl is zero.
• HintStoreError::EmptyPayload when payload is empty.
• HintStoreError::OverCapacity when accepting the hint would push the cumulative payload bytes over max_bytes.

pub fn take_for(&self, peer_idx: u32) -> Vec<Hint>

Drain every pending hint for peer_idx. Hints that have expired are dropped on the floor (and counted toward HintStoreStats::expired_total).

Returned hints are ordered by enqueue time, oldest first.

pub fn expire_now(&self, now: Instant) -> usize

Drop every hint whose deadline has passed at now. Returns the number of hints dropped. Walks the entire store; intended for the periodic drainer task.

pub fn total_len(&self) -> usize

Number of hints across every peer.

pub fn len_for(&self, peer_idx: u32) -> usize

Pending hint count for peer_idx. Useful for tests.

pub fn stats(&self) -> HintStoreStats

Snapshot the store’s accounting fields.

pub fn peers_with_hints(&self) -> Vec<u32>

Iterate the peer indices that currently have pending hints. Used by the drainer to decide which peers to ship to without holding the inner lock across the network send.

Trait Implementations

impl Debug for HintStore

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.