Module storage 

Storage backend trait and implementations.

The StorageBackend trait abstracts over where narinfo metadata and compressed NAR blobs are persisted. Three implementations are provided:

• LocalStorage — local filesystem (default)
• S3Storage — S3-compatible object storage (AWS, MinIO, R2, RustFS)
• RedisBackend — Redis L1 hot cache (sub-ms, TTL/eviction-aware)
• PgStorageBackend — Postgres L2 durable cache tier (shared, authoritative)
• TieredBackend — L1→L2→L3 read-through/write-through resolver
• StorageIndex — redb ephemeral metadata index (accelerates S3 lookups)

build_backend is the typed config-select factory: it dispatches a BackendConfig to its concrete backend (recursing for the tiered arm), so a deployment picks {disk | s3 | redis | pg | tiered} by configuration — never a silent hard-coded constructor.

Re-exports

pub use index::StorageIndex;

pub use local::LocalStorage;

pub use pg::PgCacheConn;

pub use pg::PgStorageBackend;

pub use pg::PgTable;

pub use redis::RedisBackend;

pub use redis::RedisConn;

pub use s3::S3Storage;

pub use tiered::TieredBackend;

pub use tiered::TieredTier;

pub use tiered::WritePolicy;

pub use tiered::TIERED_BACKEND_TIER;

Modules

index

redb metadata index — ephemeral local cache for S3 narinfo lookups.

local

Local filesystem storage backend.

pg

Postgres-backed L2 durable cache tier StorageBackend.

redis

Redis-backed L1 hot cache StorageBackend.

s3

S3-compatible object storage backend.

tiered

Tiered StorageBackend — the Redis L1 → Postgres L2 → object L3 read-through / write-through cache resolver.

Traits

StorageBackend

Abstraction over binary cache storage.

Functions

build_backend

Config-select factory: build the concrete StorageBackend a BackendConfig names.