Struct ConsumerCursor 

pub struct ConsumerCursor {
    pub consumer_id: String,
    pub partition_key: String,
    pub current_offset: u64,
}

Partition-specific durable read position for one consumer.

Fields

consumer_id: String

Stable consumer identifier.

partition_key: String

Durable channel partition key, formatted as channel_id:partition_index.

current_offset: u64

Current persisted read offset for this consumer and partition.

Implementations

impl ConsumerCursor

pub fn new( consumer_id: impl Into<String>, partition_key: impl Into<String>, ) -> Self

Creates a fresh cursor at offset zero.

pub fn from_persisted( consumer_id: impl Into<String>, partition_key: impl Into<String>, current_offset: u64, ) -> Self

Creates a cursor from an offset read from durable storage.

pub async fn resume( consumer_id: impl Into<String>, partition_key: impl Into<String>, store: &dyn DurableStore, ) -> Result<Self, DurabilityError>

Resumes a cursor by reading the CAS-backed offset value.

Errors

Propagates store read errors from DurableStore::read_value.

pub fn consumer_id(&self) -> &str

Returns the stable consumer identifier.

pub fn partition_key(&self) -> &str

Returns the durable channel partition key, formatted as channel_id:partition_index.

pub const fn current_offset(&self) -> u64

Returns the current persisted read offset.

pub fn cursor_key(&self) -> String

Returns the haematite CAS key used for this cursor.

pub async fn checkpoint( &mut self, store: &dyn DurableStore, new_offset: u64, ) -> Result<(), DurabilityError>

Persists a new cursor position with compare-and-swap.

Errors

Returns DurabilityError::CursorRegression when new_offset is lower than this cursor’s current offset, and propagates store CAS errors including stale checkpoints.

Trait Implementations

impl Clone for ConsumerCursor

fn clone(&self) -> ConsumerCursor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ConsumerCursor

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

Formats the value using the given formatter.

impl Eq for ConsumerCursor

impl PartialEq for ConsumerCursor

fn eq(&self, other: &ConsumerCursor) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for ConsumerCursor