dig-store-cache

The DIG Node's on-disk cache of already-verified .dig capsules — the cache + reshare leg of the content-replication flywheel (install → connect → discover → read → CACHE → reshare). Every capsule a node fetches and verifies is admitted here and becomes a discoverable holding, so every read makes content more available.

[dependencies]
dig-store-cache = "0.1"

What it is

A bounded, crash-safe, content-addressed store with pluggable (LRU by default) eviction and pinning:

• Pure filesystem primitive — no chain, no network, no keys. The caller verifies content before put (dig-node runs the NC-9 merkle/chain verify) and chooses where the cache lives.
• Path-based byte flow — capsules can be ~1 GiB, so admission stream-copies and reads go through CachedCapsule::path(); never assume a capsule fits in RAM.
• Crash-safe — atomic admission (stage → fsync → rename); disk is authoritative and the cache rebuilds from a scan on open, so a lost manifest costs only recency ordering + pins, never a capsule.

Usage

use dig_store_cache::{Cache, CacheConfig, PutOptions, CapsuleIdentity};
use std::path::Path;

let cache = Cache::open(Path::new("/var/lib/dig/cache"), CacheConfig::default())?;

// Admit an already-verified capsule.
let admission = cache.put_file(id, Path::new("/tmp/verified.dig"), PutOptions::default())?;
// `admission.evicted` = capsules the node must stop advertising.

// Read it back (streams from disk).
if let Some(hit) = cache.get(&id) {
    let path = hit.path();
}

// Advertisable holdings for the DHT provider announce.
let holdings: Vec<CapsuleIdentity> = cache.holdings();

Documentation

• SPEC.md — the normative contract (layout, admission, rebuild, eviction, invariants).
• runbooks/ — release (crates.io) + local development.

License

Licensed under either of Apache-2.0 or MIT at your option.