Struct Consumer

pub struct Consumer { /* private fields */ }

The Kafka Consumer

See module level documentation.

Implementations

impl Consumer

pub fn from_client(client: KafkaClient) -> Builder

Starts building a consumer using the given kafka client.

pub fn from_hosts(hosts: Vec<String>) -> Builder

Starts building a consumer bootstraping internally a new kafka client from the given kafka hosts.

pub fn client(&self) -> &KafkaClient

Borrows the underlying kafka client.

pub fn client_mut(&mut self) -> &mut KafkaClient

Borrows the underlying kafka client as mut.

pub fn into_client(self) -> KafkaClient

Destroys this consumer returning back the underlying kafka client.

pub fn subscriptions(&self) -> HashMap<String, Vec<i32>>

Retrieves the topic partitions being currently consumed by this consumer.

pub fn poll(&mut self) -> Result<MessageSets>

Polls for the next available message data.

pub fn group(&self) -> &str

Retrieves the group on which behalf this consumer is acting. The empty group name specifies a group-less consumer.

pub fn last_consumed_message(&self, topic: &str, partition: i32) -> Option<i64>

Retrieves the offset of the last “consumed” message in the specified partition. Results in None if there is no such “consumed” message.

pub fn consume_message( &mut self, topic: &str, partition: i32, offset: i64, ) -> Result<()>

Marks the message at the specified offset in the specified topic partition as consumed by the caller.

Note: a message with a “later/higher” offset automatically marks all preceding messages as “consumed”, this is messages with “earlier/lower” offsets in the same partition. Therefore, it is not necessary to invoke this method for every consumed message.

Results in an error if the specified topic partition is not being consumed by this consumer.

pub fn consume_messageset(&mut self, msgs: MessageSet<'_>) -> Result<()>

A convenience method to mark the given message set consumed as a whole by the caller. This is equivalent to marking the last message of the given set as consumed.

pub fn commit_consumed(&mut self) -> Result<()>

Persists the so-far “marked as consumed” messages (on behalf of this consumer’s group for the underlying topic - if any.)

See also Consumer::consume_message and Consumer::consume_messageset.

Trait Implementations

impl Debug for Consumer

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

Formats the value using the given formatter.