Struct RootfsCache 

pub struct RootfsCache { /* private fields */ }

Cache for fully-built rootfs directories.

Rootfs entries are stored under cache_dir/rootfs/<key>/. Metadata is stored alongside as <key>.meta.json.

Implementations

impl RootfsCache

pub fn new(cache_dir: &Path) -> Result<Self>

Create a new rootfs cache at the given directory.

pub fn compute_key( image_ref: &str, layer_digests: &[String], entrypoint: &[String], env: &[(String, String)], ) -> String

Compute a cache key from image components.

The key is a SHA256 hash of the concatenation of:

• image reference (e.g., “nginx:latest”)
• sorted layer digests
• entrypoint
• sorted environment variables

pub fn get(&self, key: &str) -> Result<Option<PathBuf>>

Get the path to a cached rootfs by key.

Returns None if the rootfs is not cached or the cache entry is invalid.

pub fn put( &self, key: &str, source_rootfs: &Path, description: &str, ) -> Result<PathBuf>

Store a built rootfs directory in the cache.

Copies the contents of source_rootfs into the cache keyed by key. Returns the path to the cached rootfs directory.

pub fn invalidate(&self, key: &str) -> Result<()>

Remove a cached rootfs by key.

pub fn prune(&self, max_entries: usize, max_bytes: u64) -> Result<usize>

Prune the cache to stay within the given entry count / byte limit.

Evicts least-recently-accessed entries first. Returns the number evicted.

pub fn prune_protecting( &self, max_entries: usize, max_bytes: u64, protected: &HashSet<String>, ) -> Result<usize>

Like RootfsCache::prune, but never evicts an entry whose key is in protected. Such an entry is currently serving as a box’s overlayfs lowerdir, and remove_dir_all-ing it out from under a concurrent box’s mount(2) makes the mount fail with ENOENT (“No such file or directory”). This is the same in-use guard crate::SnapshotStore::prune applies to live copy-on-write lowers — without it, two pipelines built from the same image (one cache-hit overlay box, one cache-miss box that prunes after its put) can race and corrupt each other.

pub fn list_entries(&self) -> Result<Vec<RootfsMeta>>

List all cached rootfs entries with their metadata.

pub fn total_size(&self) -> Result<u64>

Get the total size of all cached rootfs entries in bytes.

pub fn entry_count(&self) -> Result<usize>

Get the number of cached rootfs entries.

Trait Implementations

impl CacheBackend for RootfsCache

fn get(&self, key: &str) -> Result<Option<PathBuf>>

Retrieve a cached directory by key.

fn put( &self, key: &str, source_dir: &Path, description: &str, ) -> Result<PathBuf>

Store a directory tree in the cache under the given key.

fn invalidate(&self, key: &str) -> Result<()>

Remove a cached entry by key.

fn prune(&self, max_entries: usize, max_bytes: u64) -> Result<usize>

Evict entries to satisfy the given constraints.

fn list(&self) -> Result<Vec<CacheEntry>>

List all cache entries with their metadata.

fn stats(&self) -> Result<CacheStats, BoxError>

Get aggregate cache statistics.