Trait Source 

pub trait Source: Send {
    // Required methods
    fn poll(&mut self, out: &mut Out) -> Poll;
    fn on_barrier(&mut self, epoch: u64) -> Vec<u8> ;

    // Provided methods
    fn position(&mut self) -> Vec<u8>  { ... }
    fn on_commit(&mut self, _epoch: u64) { ... }
    fn on_stop(&mut self) { ... }
}

A source drives itself: the runtime calls poll until it returns Poll::Done (or the coordinator stops it).

Required Methods

fn poll(&mut self, out: &mut Out) -> Poll

fn on_barrier(&mut self, epoch: u64) -> Vec<u8>

A barrier for epoch: record the position the epoch covers; the bytes are the source’s own record of it, opaque to the runtime (a single-partition source writes it with position_record, the shape the checkpoint reads back).

Provided Methods

fn position(&mut self) -> Vec<u8>

The position now, in the record on_barrier writes — read once when the source runs dry, so every checkpoint taken after it still names where it ended (a restore then resumes it there, past everything it emitted, instead of replaying it from the start). An unbounded source never runs dry: the default records nothing.

fn on_commit(&mut self, _epoch: u64)

Every task reported epoch: the position recorded at its barrier may be committed.

fn on_stop(&mut self)

The task is ending (the source ran dry, the coordinator stopped it, or it failed): the last chance to flush anything chained into this task.

Trait Implementations

impl Source for Box<dyn Source>

fn poll(&mut self, out: &mut Out) -> Poll

fn on_barrier(&mut self, epoch: u64) -> Vec<u8>

A barrier for epoch: record the position the epoch covers; the bytes are the source’s own record of it, opaque to the runtime (a single-partition source writes it with position_record, the shape the checkpoint reads back).

fn position(&mut self) -> Vec<u8>

The position now, in the record on_barrier writes — read once when the source runs dry, so every checkpoint taken after it still names where it ended (a restore then resumes it there, past everything it emitted, instead of replaying it from the start). An unbounded source never runs dry: the default records nothing.

fn on_commit(&mut self, epoch: u64)

Every task reported epoch: the position recorded at its barrier may be committed.

fn on_stop(&mut self)

The task is ending (the source ran dry, the coordinator stopped it, or it failed): the last chance to flush anything chained into this task.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl Source for Box<dyn Source>

fn poll(&mut self, out: &mut Out) -> Poll

fn on_barrier(&mut self, epoch: u64) -> Vec<u8>

fn position(&mut self) -> Vec<u8>

fn on_commit(&mut self, epoch: u64)

fn on_stop(&mut self)

Implementors

impl<S, K> Source for Chained<S, K>

where S: Source, K: Sink,