Crate xds_cache 

xds-cache

High-performance snapshot cache for xDS resources.

This crate provides the caching layer for xDS control plane implementations:

• ShardedCache - DashMap-based concurrent cache for snapshots
• Snapshot - Immutable collection of resources for a node
• Watch - Subscription system for cache updates

Key Design Decisions

• Uses DashMap for lock-free concurrent access
• All DashMap references are dropped before any .await to prevent deadlocks
• Snapshots are immutable and atomically replaced
• Watch notifications are async and non-blocking

Example

use xds_cache::{Cache, ShardedCache, Snapshot};
use xds_core::NodeHash;

// Create a cache
let cache = ShardedCache::new();

// Build a snapshot
let snapshot = Snapshot::builder()
    .version("v1")
    .build();

// Set snapshot for a node (sync; watch notifications are async internally)
cache.set_snapshot(NodeHash::from_id("node-1"), snapshot);

Structs

CacheStats

Statistics for cache operations.

ShardedCache

A high-performance sharded cache using DashMap.

Snapshot

An immutable snapshot of xDS resources for a node.

SnapshotBuilder

Builder for creating snapshots.

SnapshotResources

Resources for a specific type within a snapshot.

Watch

A watch subscription for receiving snapshot updates.

WatchId

Unique identifier for a watch subscription.

WatchManager

Manager for watch subscriptions.

Traits

Cache

Trait for xDS snapshot caches.