Crate composefs_oci 

OCI container image support for composefs.

This crate provides functionality for working with OCI (Open Container Initiative) container images in the context of composefs. It enables importing, extracting, and mounting container images as composefs filesystems with fs-verity integrity protection.

Key functionality includes:

• Pulling container images from registries using skopeo
• Converting OCI image layers from tar format to composefs split streams
• Creating mountable filesystems from OCI image configurations
• Importing from containers-storage with zero-copy reflinks (optional feature)

Re-exports

pub use boot::boot_image;

pub use boot::remove_boot_image;

pub use oci_image::ImageInfo;

pub use oci_image::LayerInfo;

pub use oci_image::OCI_REF_PREFIX;

pub use oci_image::OciFsckError;

pub use oci_image::OciFsckResult;

pub use oci_image::OciImage;

pub use oci_image::OciImageNotFound;

pub use oci_image::OciRefNotFound;

pub use oci_image::SplitstreamInfo;

pub use oci_image::add_referrer;

pub use oci_image::layer_dumpfile;

pub use oci_image::layer_info;

pub use oci_image::layer_tar;

pub use oci_image::list_images;

pub use oci_image::list_referrers;

pub use oci_image::list_refs;

pub use oci_image::oci_fsck;

pub use oci_image::oci_fsck_image;

pub use oci_image::remove_referrer;

pub use oci_image::remove_referrers_for_subject;

pub use oci_image::resolve_ref;

pub use oci_image::tag_image;

pub use oci_image::untag_image;

pub use skopeo::pull_image;

pub use composefs;

Modules

boot

Boot image management for OCI containers.

cstor

containers-storage integration for zero-copy layer import.

design

How to create a composefs from an OCI image

image

OCI image processing and filesystem construction.

layer

Shared layer import logic for OCI container images.

layer_sync

Shared, content-agnostic splitdirfdstream producer and consumer for layer synchronisation.

layer_transport

Abstraction layer for the OCI GetLayer producer side.

oci_image

OCI image and artifact storage for composefs.

oci_layout

Direct OCI layout directory import without the skopeo proxy.

progress

Re-exported from composefs::progress; use that path directly in new code.

sealing_spec

OCI Sealing Specification for Composefs

skopeo

Container image pulling and registry interaction via skopeo/containers-image-proxy.

tar

TAR archive processing and split stream conversion.

varlink_types

Shared wire types and client proxy for the org.composefs.Oci interface.

Structs

ComponentId

Identity of a component being tracked, typically an OCI layer diff_id or an HTTP object path.

ImportStats

Statistics from an image import operation.

NullReporter

A no-op reporter that discards all events.

OciDigest

OCI content-addressable digest type (e.g. sha256:abcd...).

OciTransformOptions

Options controlling FileSystem::transform_for_oci.

OpenConfig

Parsed OCI config and its associated references.

PullOptions

Options for a pull operation.

PullResult

Result of a pull operation.

UpgradeResult

Result of a repository upgrade operation.

Enums

LocalFetchOpt

Controls whether and how the containers-storage: native import path is used when pulling images.

ProgressEvent

Events emitted during a pull or download operation.

XattrFiltering

Controls which extended attributes FileSystem::transform_for_oci keeps when processing a filesystem for OCI container image consistency.

Constants

BLOB_CONTENT_TYPE

The content-type tag used to identify non-tar OCI artifact blob splitstreams in the repository.

BOOT_IMAGE_REF_KEY

Named ref key for the V2 boot EROFS image derived from this OCI config, built with the default XattrFiltering::AllowlistOnly mode.

BOOT_IMAGE_REF_KEY_V1

Named ref key for the V1 boot EROFS image derived from this OCI config, built with the default XattrFiltering::AllowlistOnly mode.

IMAGE_REF_KEY

Named ref key for the V2 EROFS image derived from this OCI config.

IMAGE_REF_KEY_V1

Named ref key for the V1 EROFS image derived from this OCI config.

LAYER_CONTENT_TYPE

The content-type tag used to identify OCI layer (tar) splitstreams in the repository.

Traits

ProgressReporter

Receives progress events from a pull or download operation.

Functions

composefs_boot_erofs_for_config

Returns the boot EROFS ObjectID for version built with the given xattr filtering mode, from the given OCI config, if any.

composefs_boot_erofs_for_manifest

Returns the boot EROFS ObjectID for version built with the given xattr filtering mode, for an OCI image identified by manifest, if any.

composefs_erofs_for_config

Returns the composefs EROFS ObjectID for version referenced by the given OCI config, if any.

composefs_erofs_for_manifest

Returns the composefs EROFS ObjectID for an OCI image identified by manifest, if any.

extract_diff_ids

Extract ordered diff_ids from a config descriptor.

extract_layer_ids

Extract ordered layer identifiers from raw manifest and config JSON.

import_layer

Imports a container layer from a tar stream into the repository.

layer_content_id

Return the content-identifier string used to register a layer splitstream.

open_config

Opens and parses a container configuration.

pull

Pull the target image, and add the provided tag. If this is a mountable image (i.e. not an artifact), it is not unpacked by default.

sha256_content_digest

Compute the SHA-256 content digest of bytes, returning an OCI digest (e.g. sha256:abcd...).

upgrade_repo

Upgrades all tagged OCI images in the repository to the current format.

write_config

Writes a container configuration to the repository.

write_config_raw

Rewrites a container configuration in the repository from raw JSON bytes.

Type Aliases

ContentAndVerity

A tuple of (content digest, fs-verity ObjectID).

SharedReporter

Convenience type alias for a shared, type-erased progress reporter.