Struct DeadLetterQueue 

pub struct DeadLetterQueue { /* private fields */ }

A bounded dead letter queue.

Implementations

impl DeadLetterQueue

pub fn new(config: DlqConfig) -> Self

Create a new queue with the given configuration.

pub fn push(&mut self, letter: DeadLetter) -> Result<(), DlqError>

Push a dead letter into the queue.

Returns DlqError::QueueFull if the queue has reached max_size.

pub fn pop(&mut self) -> Option<DeadLetter>

Remove and return the oldest dead letter (FIFO).

pub fn peek(&self) -> Option<&DeadLetter>

Peek at the oldest dead letter without removing it.

pub fn len(&self) -> usize

Number of entries currently in the queue.

pub fn is_empty(&self) -> bool

Returns true when the queue is empty.

pub fn total_received(&self) -> u64

Total number of dead letters ever pushed into this queue (including ones that were later popped or purged).

pub fn purge_expired(&mut self, current_time_ms: u64) -> usize

Remove entries whose last_failed_at is older than max_age_ms relative to current_time_ms.

Returns the number of entries removed.

pub fn find_by_topic(&self, topic: &str) -> Vec<&DeadLetter>

Return references to all entries whose original_topic equals topic.

pub fn replay( &mut self, message_id: &str, ) -> Result<Option<DeadLetter>, DlqError>

If enable_replay is true, remove the entry with the given message_id and return it for re-processing.

Returns None if no matching entry exists. Returns Err(DlqError::ReplayDisabled) if replay is turned off.

pub fn group_by_reason(&self) -> HashMap<String, usize>

Group entries by their failure reason label and return a map of label → count.