Struct AssignmentSnapshotStore 

pub struct AssignmentSnapshotStore { /* private fields */ }

I/O wrapper for AssignmentSnapshot on an object store.

Implementations

impl AssignmentSnapshotStore

pub fn new(store: Arc<dyn ObjectStore>) -> Self

Wrap a pre-constructed object store.

pub async fn stage_recovery_proposal( &self, proposal: &AssignmentSnapshot, ) -> Result<AssignmentSnapshotRef, SnapshotError>

Stage one committed successor under its canonical content address.

Identical retries converge on the same immutable object. This does not change the durable assignment head; callers publish the returned reference through their fencing authority before materialization.

Errors

Rejects an invalid/non-committed successor or a write that cannot be reconciled exactly.

pub async fn load_recovery_proposal( &self, reference: &AssignmentSnapshotRef, ) -> Result<AssignmentSnapshot, SnapshotError>

Load and verify one exact immutable recovery proposal.

Errors

Rejects a missing, malformed, non-canonical, or reference-mismatched object.

pub async fn load(&self) -> Result<Option<AssignmentSnapshot>, SnapshotError>

Load the current (highest-versioned) snapshot; Ok(None) on fresh cluster.

Errors

Object-store I/O or JSON decode failure.

pub async fn load_version( &self, version: u64, ) -> Result<Option<AssignmentSnapshot>, SnapshotError>

Load a specific version’s snapshot. Ok(None) if that version was never written or has been pruned.

Errors

Object-store I/O or JSON decode failure.

pub async fn load_drain_transition( &self, version: u64, ) -> Result<Option<AssignmentDrainTransition>, SnapshotError>

Load the immutable drain transition underlying a materialized assignment version.

A terminal load_version result intentionally contains only the installed assignment. Cluster readers use this accessor to bind that materialized result back to the shared authority decision before adoption. Ordinary assignment versions return None.

Errors

Object-store I/O, JSON decode failure, or a malformed base snapshot.

pub async fn save_if_absent( &self, snapshot: &AssignmentSnapshot, ) -> Result<Option<AssignmentSnapshot>, SnapshotError>

CAS-create the version-one seed. Ok(None) means another initial writer won.

Errors

Object-store I/O or JSON encode failure.

pub async fn save_if_version( &self, snapshot: &AssignmentSnapshot, prior_version: u64, ) -> Result<RotateOutcome, SnapshotError>

Rotate to snapshot assuming the current durable version is prior_version. Returns RotateOutcome::Conflict carrying the winner’s snapshot if a racer produced prior_version + 1 first.

Errors

Object-store I/O, JSON encode, or a non-monotonic version bump (caller bug).

pub async fn finalize_drain( &self, draining: &AssignmentSnapshot, proposal: &AssignmentSnapshot, ) -> Result<RotateOutcome, SnapshotError>

Append exactly one immutable winner for a draining object: its target or a rollback.

The object version is intentionally unchanged: source receipts certify the target assignment version, so committing the map under another version would discard the very identity they proved. PutMode::Create makes commit versus abort a store-level race with one winner on local and cloud backends; the original transition remains auditable. Cluster callers must first serialize the verdict through LeaderLeaseStore; this method only materializes that already-authoritative verdict.

Errors

Rejects a stale/non-draining expected value, an unrelated proposal, or a non-head object.

pub async fn prune_before(&self, before: u64) -> Result<(), SnapshotError>

Delete every snapshot object with version < before. Idempotent — missing objects are tolerated.

Errors

Object-store I/O.

Trait Implementations

impl Debug for AssignmentSnapshotStore

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.