Struct TransactionalPartitions 

pub struct TransactionalPartitions { /* private fields */ }

Transactional publishers, one per source partition, materialized on first use.

Kafka permits one open transaction per producer and one live producer per transactional id (initializing a second fences the first), so concurrent transactional handlers need one producer each. The source partition is the natural scope: under the default LaneKey::Partition worker pool a partition’s deliveries process serially on one lane, so a publisher per partition gives every lane an independent transaction with no coordination. The id set ("{base}-p{partition}") follows the topic’s partitions rather than the worker count: changing workers(n) neither changes the ids nor weakens zombie fencing - the scheme Kafka Streams uses for its per-task producers.

Not for LaneKey::RecordKey pools: record-key lanes spread one partition across lanes, so two lanes would share a partition’s publisher and collide on its single transaction (KafkaError::TransactionBusy).

Clones share the cache, so one injected handle serves every handler invocation.

Implementations

impl TransactionalPartitions

pub async fn for_partition( &self, partition: i32, ) -> Result<KafkaTransactionalPublisher, KafkaError>

The publisher owning partition’s transactional id, created and initialized on first use.

partition is the delivery’s source partition (KafkaContext’s Partition field in a handler); passing anything else still works but forfeits the serialization argument that makes the per-partition scope safe.

Errors

Returns KafkaError::Closed once the broker has shut down and KafkaError::Publish when the partition’s producer cannot be created or its transactions cannot be initialized.

Panics

Panics when the internal cache mutex is poisoned, which requires a prior panic while materializing a publisher (an invariant violation, not an operational failure).

Trait Implementations

impl Clone for TransactionalPartitions

fn clone(&self) -> TransactionalPartitions

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TransactionalPartitions

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

Formats the value using the given formatter.