Struct ClientManager 

pub struct ClientManager { /* private fields */ }

Manages all connected WebSocket clients using lock-free DashMap.

Key design decisions:

• Uses DashMap for lock-free concurrent access to client registry
• Uses try_send instead of send to never block on slow clients
• Disconnects clients that are backpressured (queue full) to prevent cascade failures
• All public methods are non-blocking or use fine-grained per-key locks

Implementations

impl ClientManager

pub fn new() -> Self

pub fn with_timeout(self, timeout: Duration) -> Self

pub fn with_message_queue_size(self, queue_size: usize) -> Self

pub fn add_client(&self, client_id: Uuid, ws_sender: WebSocketSender)

Add a new client connection.

Spawns a dedicated sender task for this client that reads from its mpsc channel and writes to the WebSocket. If the WebSocket write fails, the client is automatically removed from the registry.

pub fn remove_client(&self, client_id: Uuid)

Remove a client from the registry.

pub fn client_count(&self) -> usize

Get the current number of connected clients.

This is lock-free and returns an approximate count (may be slightly stale under high concurrency, which is fine for max_clients checks).

pub fn send_to_client( &self, client_id: Uuid, data: Arc<Bytes>, ) -> Result<(), SendError>

Send data to a specific client (non-blocking).

This method NEVER blocks. If the client’s queue is full, the client is considered too slow and is disconnected to prevent cascade failures. Use this for live streaming updates.

For initial snapshots where you expect to send many messages at once, use send_to_client_async instead which will wait for queue space.

pub async fn send_to_client_async( &self, client_id: Uuid, data: Arc<Bytes>, ) -> Result<(), SendError>

Send data to a specific client (async, waits for queue space).

This method will wait if the client’s queue is full, allowing the client time to catch up. Use this for initial snapshots where you need to send many messages at once.

For live streaming updates, use send_to_client instead which will disconnect slow clients rather than blocking.

pub fn update_subscription( &self, client_id: Uuid, subscription: Subscription, ) -> bool

Update the subscription for a client.

pub fn update_client_last_seen(&self, client_id: Uuid)

Update the last_seen timestamp for a client.

pub fn get_subscription(&self, client_id: Uuid) -> Option<Subscription>

Get the subscription for a client.

pub fn has_client(&self, client_id: Uuid) -> bool

Check if a client exists.

pub async fn add_client_subscription( &self, client_id: Uuid, sub_key: String, token: CancellationToken, )

pub async fn remove_client_subscription( &self, client_id: Uuid, sub_key: &str, ) -> bool

pub async fn cancel_all_client_subscriptions(&self, client_id: Uuid)

pub fn cleanup_stale_clients(&self) -> usize

Remove stale clients that haven’t been seen within the timeout period.

pub fn start_cleanup_task(&self)

Start a background task that periodically cleans up stale clients.

Trait Implementations

impl Clone for ClientManager

fn clone(&self) -> ClientManager

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for ClientManager

fn default() -> Self

Returns the “default value” for a type.