Enum KinesisPosition 

pub enum KinesisPosition {
    Horizon,
    Latest,
    Timestamp(u64),
    Sequence {
        shard: String,
        sequence: String,
    },
}

A position in the stream’s retained log: the whole start vocabulary of this broker, accepted by Seeker::seek and by the start_at(..) clause of #[subscriber(..)].

Repositioning resets the checkpoint bookkeeping of every shard it moves: acknowledgements of records delivered before the seek stop advancing the watermark, so a stale checkpoint cannot drag the cursor back over the position just taken. Records from the new position onward are delivered again, which at-least-once permits.

Without a position a subscription resumes from the stored checkpoint of each shard, and starts at the tip on a shard that has none.

Examples

use ruststream_kinesis::KinesisPosition;

// Every retained record on every shard, replayed from the trim horizon.
let backlog = KinesisPosition::horizon();

Variants

Horizon

The trim horizon: everything the stream still retains.

Stream-wide - it applies to every shard of the subscription, including shards discovered later (the children of a split or merge).

Latest

The tip: only records published after the reposition.

Stream-wide, and the position a shard without a checkpoint starts at by default.

Timestamp(u64)

The first record at or after this timestamp, in milliseconds since the Unix epoch.

Stream-wide; each shard opens at its own first record from that instant.

Sequence

Exactly one record on one shard.

This is the pinned form the framework defines for captured positions (Positioned::position): seeking to one redelivers that very record. It addresses a single shard, so it moves that shard’s reader only, the way a partitioned log seeks per partition, and the shard must be owned and live.

Fields

shard: String

The shard the position lives on.

sequence: String

The record’s sequence number.

Implementations

impl KinesisPosition

pub const fn horizon() -> Self

The trim horizon, for every shard: see KinesisPosition::Horizon.

pub const fn latest() -> Self

The tip, for every shard: see KinesisPosition::Latest.

pub const fn timestamp(millis: u64) -> Self

A wall-clock instant (milliseconds since the Unix epoch), for every shard: see KinesisPosition::Timestamp.

pub fn sequence(shard: impl Into<String>, sequence: impl Into<String>) -> Self

One record on one shard: see KinesisPosition::Sequence.

Captured positions come from Positioned::position; this constructor is for a sequence number carried in from elsewhere (an operator’s replay request, say).

Trait Implementations

impl Clone for KinesisPosition

fn clone(&self) -> KinesisPosition

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for KinesisPosition

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

Formats the value using the given formatter.

impl Eq for KinesisPosition

impl PartialEq for KinesisPosition

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for KinesisPosition