Struct LeaseKey 

pub struct LeaseKey { /* private fields */ }

The name one shard’s lease and checkpoint live under: the stream and the shard id.

Shard ids repeat across streams (the first shard of every stream is shardId-000000000000), so a store keys by both, and one store serves every stream a broker consumes. The stream is the name the subscription’s KinesisStream was given.

Examples

A store over a string-keyed table writes each shard’s row under the key’s stream:shard form:

use std::collections::HashMap;
use std::sync::Mutex;

use futures::future::BoxFuture;
use ruststream_kinesis::{LeaseError, LeaseKey, LeaseState, LeaseStore};

/// Checkpoints for a single instance, which owns every shard.
#[derive(Default)]
pub struct Checkpoints(Mutex<HashMap<String, String>>);

impl LeaseStore for Checkpoints {
    fn checkpoint<'a>(
        &'a self,
        key: &'a LeaseKey,
        _owner: &'a str,
        sequence: &'a str,
    ) -> BoxFuture<'a, Result<bool, LeaseError>> {
        Box::pin(async move {
            let mut rows = self.0.lock().map_err(|e| e.to_string())?;
            rows.insert(key.to_string(), sequence.to_owned());
            Ok(true)
        })
    }

    fn read<'a>(&'a self, key: &'a LeaseKey) -> BoxFuture<'a, Result<LeaseState, LeaseError>> {
        Box::pin(async move {
            let rows = self.0.lock().map_err(|e| e.to_string())?;
            let mut state = LeaseState::default();
            state.checkpoint = rows.get(&key.to_string()).cloned();
            Ok(state)
        })
    }
}

Implementations

impl LeaseKey

pub fn new(stream: impl Into<Arc<str>>, shard: impl Into<Arc<str>>) -> Self

The lease of shard on stream.

pub fn stream(&self) -> &str

The stream the shard belongs to.

pub fn shard(&self) -> &str

The shard id, unique within its stream only.

Trait Implementations

impl Clone for LeaseKey

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LeaseKey

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

Formats the value using the given formatter.

impl Display for LeaseKey

stream:shard, the form a store that keeps one string key writes. A stream name holds no colon, so the form is unambiguous.

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

Formats the value using the given formatter.

impl Eq for LeaseKey

impl Hash for LeaseKey

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LeaseKey

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for LeaseKey