Crate zub 

zub - git-like object tree

a content-addressed filesystem store for rootfs fragments with git-like semantics. similar in spirit to ostree but simpler, designed for composing Linux system images.

Core concepts

• Blob: content-addressed file data (compressed with zstd)
• Tree: a serialized directory structure (CBOR + zstd)
• Commit: a snapshot of a tree with metadata (CBOR + zstd)
• Ref: a named pointer to a commit (hierarchical, like git branches)

Hash format

blob hash = SHA256(uid | gid | mode | xattr_count | xattrs… | content)

where xattrs are sorted by name and each is: name_len | name | value_len | value

Example usage

use zub::{Repo, ops};
use std::path::Path;

// initialize a repository
let repo = Repo::init(Path::new("/path/to/repo")).unwrap();

// commit a directory
let hash = ops::commit(&repo, Path::new("/source"), "my/ref", Some("initial commit"), None).unwrap();

// checkout to a directory
ops::checkout(&repo, "my/ref", Path::new("/destination"), ops::CheckoutOptions::default()).unwrap();

Re-exports

pub use ops::du;

pub use ops::stats;

pub use ops::truncate_history;

pub use ops::RefSize;

pub use ops::RepoStats;

pub use ops::TruncateStats;

pub use types::ChangeKind;

pub use types::Commit;

pub use types::DiffEntry;

pub use types::EntryKind;

pub use types::SparseRegion;

pub use types::Tree;

pub use types::TreeEntry;

pub use types::Xattr;

Modules

fs

ops

high-level operations on zub repositories

transport

transport layer for remote operations

types

Structs

Config

repository configuration stored in config.toml

Hash

SHA-256 hash used for content addressing

MapEntry

a single range in a uid/gid mapping

NsConfig

namespace configuration with uid and gid mappings

Repo

a zub repository

Enums

Error

error type for zuboperations

Functions

blob_exists

check if a blob exists in the object store

commit_path

get the filesystem path to a commit object

compute_blob_hash

compute blob hash over (uid, gid, mode, xattrs, content)

current_gid_map

read current process gid map from /proc/self/gid_map

current_uid_map

read current process uid map from /proc/self/uid_map

delete_ref

delete a ref

delete_refs_matching

delete refs matching a glob pattern, returns list of deleted refs

inside_to_outside

convert inside (logical namespace) id to outside (on-disk) id

list_refs

list all refs

list_refs_matching

list refs matching a glob pattern

mappings_equal

check if two namespace configs are equivalent (same mappings)

outside_to_inside

convert outside (on-disk) id to inside (logical namespace) id

parse_id_map

parse /proc/self/uid_map or gid_map format format: “inside_start outside_start count” per line, whitespace separated

read_blob

read blob content

read_commit

read a commit from the object store

read_ref

read a ref

read_tree

read a tree from the object store

ref_exists

check if a ref exists

remap

remap an id from one namespace to another old_outside -> inside (via old_map) -> new_outside (via new_map)

resolve_ref

resolve a ref or hash string to a hash

tree_path

get the filesystem path to a tree object

write_blob

write a blob to the object store

write_commit

write a commit to the object store

write_ref

write a ref (create or update)

write_tree

write a tree to the object store

Type Aliases

Result