Struct RequestDeduplicator 

pub struct RequestDeduplicator {
    pub max_waiters_per_key: usize,
    pub request_timeout: Duration,
    pub stats: DedupStats,
    /* private fields */
}

Deduplicates concurrent requests for the same CID.

try_acquire returns Leader to the first caller; all subsequent callers for the same CID before resolve is called receive a Waiter handle. Once the leader calls resolve, the flight record is marked complete and removed, so the next caller starts a fresh leader/waiter cycle.

If the waiter queue reaches max_waiters_per_key, additional callers are promoted to Leader so they can independently issue their own request.

Fields

max_waiters_per_key: usize

Maximum number of waiters allowed per CID before overflow callers become leaders.

request_timeout: Duration

Duration after which unresolved flight records are considered stale.

stats: DedupStats

Atomic counters.

Implementations

impl RequestDeduplicator

pub fn new(max_waiters_per_key: usize, request_timeout: Duration) -> Self

Creates a new deduplicator with the given waiter cap and request timeout.

Arguments

• max_waiters_per_key – once this many waiters exist for a CID, additional callers are promoted to Leader instead of waiting.
• request_timeout – flights older than this are pruned by timeout_expired_flights.

pub fn try_acquire(&self, cid: &str) -> AcquireResult

Attempt to acquire the right to issue the outbound request for cid.

Returns Leader if no in-flight record exists (or the waiter queue is full), or Waiter(handle) if the caller should coalesce.

pub fn resolve(&self, cid: &str, result: ResolveResult) -> bool

Mark the in-flight record for cid as resolved with result.

The flight record is removed from in_flight; the number of waiters that were coalesced is added to DedupStats::total_coalesced. Returns true if an active flight was found and resolved, false if no matching record existed.

pub fn timeout_expired_flights(&self) -> usize

Prune all flight records that have exceeded request_timeout.

Returns the number of records removed.

pub fn in_flight_count(&self) -> usize

Returns the number of currently in-flight records.

pub fn waiter_count_for(&self, cid: &str) -> Option<usize>

Returns the current waiter count for a specific CID, or None if no in-flight record exists for that CID.

Trait Implementations

impl Debug for RequestDeduplicator

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

Formats the value using the given formatter.

impl Default for RequestDeduplicator

fn default() -> Self

Returns the “default value” for a type.