Struct rdkafka::consumer::BaseConsumer
source · [−]pub struct BaseConsumer<C = DefaultConsumerContext> where
C: ConsumerContext, { /* private fields */ }
Expand description
A low-level consumer that requires manual polling.
This consumer must be periodically polled to make progress on rebalancing, callbacks and to receive messages.
Implementations
Polls the consumer for new messages.
It won’t block for more than the specified timeout. Use zero Duration
for non-blocking
call. With no timeout it blocks until an event is received.
This method should be called at regular intervals, even if no message is expected, to serve any queued callbacks waiting to be called. This is especially important for automatic consumer rebalance, as the rebalance function will be executed by the thread calling the poll() function.
Lifetime
The returned message lives in the memory of the consumer and cannot outlive it.
pub fn iter(&self) -> Iter<'_, C>ⓘNotable traits for Iter<'a, C>impl<'a, C> Iterator for Iter<'a, C> where
C: ConsumerContext, type Item = KafkaResult<BorrowedMessage<'a>>;
pub fn iter(&self) -> Iter<'_, C>ⓘNotable traits for Iter<'a, C>impl<'a, C> Iterator for Iter<'a, C> where
C: ConsumerContext, type Item = KafkaResult<BorrowedMessage<'a>>;
impl<'a, C> Iterator for Iter<'a, C> where
C: ConsumerContext, type Item = KafkaResult<BorrowedMessage<'a>>;
Returns an iterator over the available messages.
It repeatedly calls poll
with no timeout.
Note that it’s also possible to iterate over the consumer directly.
Examples
All these are equivalent and will receive messages without timing out.
loop {
let message = consumer.poll(None);
// Handle the message
}
for message in consumer.iter() {
// Handle the message
}
for message in &consumer {
// Handle the message
}
pub fn split_partition_queue(
self: &Arc<Self>,
topic: &str,
partition: i32
) -> Option<PartitionQueue<C>>
pub fn split_partition_queue(
self: &Arc<Self>,
topic: &str,
partition: i32
) -> Option<PartitionQueue<C>>
Splits messages for the specified partition into their own queue.
If the topic
or partition
is invalid, returns None
.
After calling this method, newly-fetched messages for the specified
partition will be returned via PartitionQueue::poll
rather than
BaseConsumer::poll
. Note that there may be buffered messages for the
specified partition that will continue to be returned by
BaseConsumer::poll
. For best results, call split_partition_queue
before the first call to BaseConsumer::poll
.
You must continue to call BaseConsumer::poll
, even if no messages are
expected, to serve callbacks.
Note that calling Consumer::assign
will deactivate any existing
partition queues. You will need to call this method for every partition
that should be split after every call to assign
.
Beware that this method is implemented for &Arc<Self>
, not &self
.
You will need to wrap your consumer in an Arc
in order to call this
method. This design permits moving the partition queue to another thread
while ensuring the partition queue does not outlive the consumer.
Trait Implementations
Returns the current consumer group metadata associated with the consumer. Read more
Subscribes the consumer to a list of topics.
Unsubscribes the current subscription list.
Manually assigns topics and partitions to the consumer. If used, automatic consumer rebalance won’t be activated. Read more
Seeks to offset
for the specified topic
and partition
. After a
successful call to seek
, the next poll of the consumer will return the
message with offset
. Read more
fn commit(
&self,
topic_partition_list: &TopicPartitionList,
mode: CommitMode
) -> KafkaResult<()>
fn commit(
&self,
topic_partition_list: &TopicPartitionList,
mode: CommitMode
) -> KafkaResult<()>
Commits the offset of the specified message. The commit can be sync (blocking), or async. Notice that when a specific offset is committed, all the previous offsets are considered committed as well. Use this method only if you are processing messages in order. Read more
Commits the current consumer state. Notice that if the consumer fails after a message has been received, but before the message has been processed by the user code, this might lead to data loss. Check the “at-least-once delivery” section in the readme for more information. Read more
Commit the provided message. Note that this will also automatically commit every message with lower offset within the same partition. Read more
Stores offset to be used on the next (auto)commit. When
using this enable.auto.offset.store
should be set to false
in the
config. Read more
Like Consumer::store_offset
, but the offset to store is derived from
the provided message. Read more
Store offsets to be used on the next (auto)commit. When using this
enable.auto.offset.store
should be set to false
in the config. Read more
Returns the current topic subscription.
Returns the current partition assignment.
Retrieves the committed offsets for topics and partitions.
fn committed_offsets<T: Into<Timeout>>(
&self,
tpl: TopicPartitionList,
timeout: T
) -> KafkaResult<TopicPartitionList>
fn committed_offsets<T: Into<Timeout>>(
&self,
tpl: TopicPartitionList,
timeout: T
) -> KafkaResult<TopicPartitionList>
Retrieves the committed offsets for specified topics and partitions.
fn offsets_for_timestamp<T: Into<Timeout>>(
&self,
timestamp: i64,
timeout: T
) -> KafkaResult<TopicPartitionList>
fn offsets_for_timestamp<T: Into<Timeout>>(
&self,
timestamp: i64,
timeout: T
) -> KafkaResult<TopicPartitionList>
Looks up the offsets for this consumer’s partitions by timestamp.
fn offsets_for_times<T: Into<Timeout>>(
&self,
timestamps: TopicPartitionList,
timeout: T
) -> KafkaResult<TopicPartitionList>
fn offsets_for_times<T: Into<Timeout>>(
&self,
timestamps: TopicPartitionList,
timeout: T
) -> KafkaResult<TopicPartitionList>
Looks up the offsets for the specified partitions by timestamp.
Retrieve current positions (offsets) for topics and partitions.
fn fetch_metadata<T: Into<Timeout>>(
&self,
topic: Option<&str>,
timeout: T
) -> KafkaResult<Metadata>
fn fetch_metadata<T: Into<Timeout>>(
&self,
topic: Option<&str>,
timeout: T
) -> KafkaResult<Metadata>
Returns the metadata information for the specified topic, or for all topics in the cluster if no topic is specified. Read more
Returns the low and high watermarks for a specific topic and partition.
fn fetch_group_list<T: Into<Timeout>>(
&self,
group: Option<&str>,
timeout: T
) -> KafkaResult<GroupList>
fn fetch_group_list<T: Into<Timeout>>(
&self,
group: Option<&str>,
timeout: T
) -> KafkaResult<GroupList>
Returns the group membership information for the given group. If no group is specified, all groups will be returned. Read more
Pauses consumption for the provided list of partitions.
Resumes consumption for the provided list of partitions.
Reports the rebalance protocol in use.
Returns a reference to the ConsumerContext
used to create this
consumer. Read more
Creates a client from a client configuration. The default client context will be used. Read more
Creates a new BaseConsumer
starting from a ClientConfig
.
fn from_config_and_context(
config: &ClientConfig,
context: C
) -> KafkaResult<BaseConsumer<C>>
fn from_config_and_context(
config: &ClientConfig,
context: C
) -> KafkaResult<BaseConsumer<C>>
Creates a client from a client configuration and a client context.
type Item = KafkaResult<BorrowedMessage<'a>>
type Item = KafkaResult<BorrowedMessage<'a>>
The type of the elements being iterated over.