Struct MemoryBackend 

pub struct MemoryBackend { /* private fields */ }

An in-memory Backend. Cloning gives another handle onto the same state.

let backend = MemoryBackend::new();
let same_state = backend.clone();
assert_eq!(same_state.pending("nothing.here"), 0);

Implementations

impl MemoryBackend

pub fn new() -> MemoryBackend

Create an empty backend with no queues declared.

pub fn pending(&self, queue: &str) -> usize

Number of messages waiting in queue.

Messages that were handed to a consumer but not yet settled are not counted, and neither are delayed publishes whose delay has not elapsed.

pub fn acked(&self, queue: &str) -> Vec<Envelope>

Envelopes that were acked on queue, in ack order.

A successful Delivery::retry acks the original envelope, so it shows up here too (the rescheduled copy arrives separately with attempt + 1).

pub fn deferred(&self, queue: &str) -> usize

Number of deferred envelopes still sitting in queue’s hold.

These are the ones Backend::defer (or Delivery::defer) accepted but whose delay has not elapsed: they are not pending yet and no consumer can see them. The count drops back to zero as each hold expires or, if the backend was closed in the meantime, as each held envelope is dropped.

pub fn dead_letters(&self, queue: &str) -> Vec<(Envelope, String)>

Envelopes that were dead-lettered on queue, with the reason given.

pub fn queue_names(&self) -> Vec<String>

Names of every declared (or implicitly created) queue.

pub fn queue_config(&self, queue: &str) -> Option<QueueConfig>

Config recorded for queue by the first declare call, if any.

pub fn is_closed(&self) -> bool

Whether Backend::close has been called.

Trait Implementations

impl Backend for MemoryBackend

fn declare<'life0, 'life1, 'async_trait>( &'life0 self, queues: &'life1 [QueueConfig], ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, MemoryBackend: 'async_trait,

Idempotently create all queues (plus any retry / dead-letter infrastructure).

fn publish<'life0, 'life1, 'async_trait>( &'life0 self, envelope: &'life1 Envelope, delay: Option<Duration>, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, MemoryBackend: 'async_trait,

Publish envelope to envelope.queue, optionally delayed.

fn defer<'life0, 'life1, 'async_trait>( &'life0 self, envelope: &'life1 Envelope, delay: Duration, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, MemoryBackend: 'async_trait,

Publish envelope into a hold that releases it onto envelope.queue after delay. This is the publish half of Delivery::defer, also used by crate::Producer::defer.

fn consume<'life0, 'life1, 'async_trait>( &'life0 self, queue: &'life1 QueueConfig, ) -> Pin<Box<dyn Future<Output = Result<Pin<Box<dyn Stream<Item = Result<Box<dyn Delivery>, Error>> + Send>>, Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, MemoryBackend: 'async_trait,

Start consuming queue with the given prefetch. The stream ends when the backend is closed or the connection is lost.

fn close<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, MemoryBackend: 'async_trait,

Graceful shutdown: stop all consumers, flush, close connections.

impl Clone for MemoryBackend

fn clone(&self) -> MemoryBackend

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MemoryBackend

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

Formats the value using the given formatter.

impl Default for MemoryBackend

fn default() -> MemoryBackend

Returns the “default value” for a type.