Struct ConnectionDrainer 

pub struct ConnectionDrainer { /* private fields */ }

Manages graceful connection draining for orderly node shutdown.

Tracks all registered connections, transitions them through the Active → Draining → Drained lifecycle, and collects statistics.

Implementations

impl ConnectionDrainer

pub fn new(config: DrainerConfig) -> Self

Create a new drainer with the given configuration.

pub fn register_connection(&mut self, peer_id: &str) -> u64

Register a new active connection and return its unique id.

pub fn start_drain(&mut self, conn_id: u64) -> Result<(), String>

Begin draining a single connection.

Returns an error if the connection does not exist or is already draining/drained.

pub fn start_drain_all(&mut self)

Begin draining every currently-active connection.

pub fn complete_request(&mut self, conn_id: u64) -> Result<(), String>

Record the completion of one request on a connection.

If the connection is draining and pending drops to zero it transitions to Drained.

pub fn add_request(&mut self, conn_id: u64) -> Result<(), String>

Add a new request to a connection.

If the connection is draining and reject_new_requests is set, the request is rejected and the rejection counter incremented.

pub fn check_drained(&mut self, conn_id: u64) -> Option<DrainState>

Check whether a connection has been fully drained.

Returns Some(DrainState::Drained) when pending requests reach zero while draining, Some(current_state) otherwise, or None if the connection does not exist.

pub fn check_timeouts(&mut self, now: u64) -> Vec<u64>

Force-drain connections whose drain timeout has elapsed.

now is a monotonic timestamp in milliseconds. Returns the ids of connections that were force-drained.

pub fn remove_drained(&mut self) -> usize

Remove all connections in the Drained state and return how many were removed.

pub fn get_connection(&self, conn_id: u64) -> Option<&DrainableConnection>

Look up a connection by id.

pub fn active_count(&self) -> usize

Number of connections in the Active state.

pub fn draining_count(&self) -> usize

Number of connections in the Draining state.

pub fn is_fully_drained(&self) -> bool

Returns true when there are no active or draining connections.

pub fn stats(&self) -> &DrainerStats

Reference to the current statistics.

pub fn set_drain_start_time(&mut self, conn_id: u64, timestamp_ms: u64)

Set a real wall-clock start time on a draining connection.

This is a helper so callers that use start_drain followed by check_timeouts(now) can record accurate timestamps.