Crate crabka_client_consumer

Expand description

Subscribe-style consumer client for Apache Kafka in Rust.

Builds on crabka-client-core for transport; adds the classic consumer-group lifecycle (JoinGroup → SyncGroup → Heartbeat → Fetch → OffsetCommit → LeaveGroup) and a built-in heartbeat task.

§Quick start

use crabka_client_consumer::{AutoOffsetReset, Consumer};
use std::time::Duration;

let mut consumer = Consumer::builder()
    .bootstrap("localhost:9092")
    .group_id("my-group")
    .client_id("my-app")
    .auto_offset_reset(AutoOffsetReset::Earliest)
    .subscribe(["my-topic".to_string()])
    .build()
    .await?;

loop {
    let records = consumer.poll(Duration::from_millis(500)).await?;
    for _r in records {
        // ... handle r ...
    }
    consumer.commit_sync().await?;
}

use crabka_client_consumer::{ShareAckMode, ShareAckType, ShareConsumer};
use std::time::Duration;

let mut consumer = ShareConsumer::builder()
    .bootstrap("localhost:9092")
    .group_id("share-workers")
    .subscribe(["jobs".to_string()])
    .ack_mode(ShareAckMode::Explicit)
    .build()
    .await?;

let records = consumer.poll(Duration::from_secs(1)).await?;
for record in &records {
    consumer.acknowledge(record, ShareAckType::Accept)?;
}
consumer.commit().await?;

§Capabilities and boundaries

This crate owns consumer-facing semantics: classic group membership, assignment, fetch/poll, offset commit, cooperative shutdown, and KIP-932 share-group consumption. It intentionally does not duplicate admin-client surfaces such as DescribeGroups/ListGroups, and manual partition fetches remain available through the lower-level helpers in crabka-client-core. Transactional consume-process-produce workflows use this crate’s ConsumerGroupMetadata together with crabka-client-producer’s send_offsets_to_transaction support.

§Cargo features

None for now.

Structs§

Consumer: Subscribe-style consumer handle. Construct via Consumer::builder.
ConsumerGroupMetadata: The identity a consumer presents to a transactional producer for KIP-447 offset-commit fencing. Mirrors the JVM’s org.apache.kafka.clients.consumer.ConsumerGroupMetadata.
ConsumerRecord: One record returned by Consumer::poll.
ShareConsumer: A share-group consumer. Construct via ShareConsumer::builder.
ShareConsumerRecord: One record delivered by ShareConsumer::poll.

Enums§

Assignor
AutoOffsetReset: What to do when a partition has no committed offset.
ConsumerError: Errors returned by Consumer.
IsolationLevel: Controls which records are visible to this consumer.
ShareAckMode: How acquired records are acknowledged.
ShareAckType: The disposition of an acknowledged record (KIP-932 wire codes).