Module barrier 

Barrier cuts: an exact, reproducible point in every input at once.

A krabka broker injects an epoch-stamped marker into every partition of a named barrier group and publishes the resulting cut, one marker offset per partition, to the internal topic __barrier_state. The marker is a Kafka control record, so no consumer ever receives one. A task aligns on a cut by comparing its consumed offsets against the cut’s offsets, never by watching for a marker.

Key Types

• BarrierCut — one epoch’s cut, with the marker offset of each partition.
• CutReader — reads published cuts from __barrier_state.
• BarrierAlignment — tells a runtime which group to align on, and where to keep each cut’s snapshot.
• BarrierListener — the callback that fires when a barrier is reached.

Examples

use std::sync::Arc;

use krabka_client_streams::{barrier::BarrierAlignment, store::snapshot::FileSnapshotStore};

let snapshots = Arc::new(FileSnapshotStore::new("/var/lib/app/state"));
BarrierAlignment::on("transactions", snapshots)

Structs

Barrier

The barrier a stream thread reached: the cut, the tasks it snapshotted, and the offsets it committed.

BarrierAlignment

Tells a stream thread which barrier group to align on.

BarrierCut

One epoch’s cut across every partition of a barrier group.

CutReader

Reads the cuts a barrier coordinator published to __barrier_state.

Enums

CutStatus

Whether the coordinator reached every partition of a barrier group.

Constants

BARRIER_STATE_TOPIC

The internal topic a krabka broker publishes barrier state to.

Traits

BarrierListener

Receives a barrier after a stream thread commits at a cut.

Functions

decode_barrier_cut

Decodes one record of BARRIER_STATE_TOPIC into a cut.