Struct ConnectionPoolManager 

pub struct ConnectionPoolManager { /* private fields */ }

Adaptive connection pool with health checking, multiple acquisition policies, idle/lifetime eviction, event streaming, and dynamic resize.

Implementations

impl ConnectionPoolManager

pub fn new(config: CpmPoolConfig) -> Self

Create a new pool with the given configuration.

Returns CpmPoolError::InvalidConfiguration if min > max or max == 0.

pub fn validate_config(config: &CpmPoolConfig) -> Result<(), CpmPoolError>

Validate the current configuration.

pub fn add_connection( &mut self, address: String, tags: Vec<String>, ) -> Result<u64, CpmPoolError>

Add a new connection to the pool.

Returns the new connection’s unique ID, or CpmPoolError::PoolExhausted if max_connections has been reached.

pub fn add_connection_at( &mut self, address: String, tags: Vec<String>, created_at: u64, ) -> Result<u64, CpmPoolError>

Add a connection with an explicit creation timestamp (useful in tests).

pub fn acquire(&mut self, current_ts: u64) -> Result<u64, CpmPoolError>

Acquire an idle connection according to the configured AcquirePolicy.

Returns the ID of the acquired connection, or an error if:

• No idle connections exist and the pool is at capacity → CpmPoolError::PoolExhausted
• All connections are busy and no idle ones can be selected → CpmPoolError::AcquireTimeout (using acquire_timeout_us as the waited value)

pub fn release( &mut self, conn_id: u64, current_ts: u64, health_degraded: bool, ) -> Result<(), CpmPoolError>

Release a previously acquired connection back to Idle.

If health_degraded is true, the health score is reduced by 0.1 (floored at 0.0).

pub fn remove_connection(&mut self, conn_id: u64) -> Result<(), CpmPoolError>

Permanently remove a connection from the pool.

pub fn health_check( &mut self, conn_id: u64, score: f64, current_ts: u64, ) -> Result<PoolEvent, CpmPoolError>

Record the result of a health check for the given connection.

If score < 0.3, emits a PoolEvent::HealthCheckFailed and returns it. Otherwise returns PoolEvent::ConnectionAdded as a no-op sentinel (callers should match on the returned variant).

pub fn run_maintenance(&mut self, current_ts: u64) -> Vec<PoolEvent>

Evict connections that have exceeded idle or absolute lifetime limits.

Returns a list of PoolEvent::ConnectionRemoved events for each evicted connection.

pub fn resize(&mut self, new_max: usize) -> Result<(), CpmPoolError>

Resize the pool’s maximum connection limit.

When shrinking, excess idle connections are drained (closed) immediately.

pub fn drain(&mut self) -> Vec<u64>

Close all connections in insertion order and return their IDs.

pub fn connections_with_tag(&self, tag: &str) -> Vec<&PooledConnection>

Return references to all connections that carry the given tag.

pub fn stats(&self) -> CpmPoolStats

Compute a statistics snapshot.

pub fn drain_events(&mut self) -> Vec<PoolEvent>

Drain and return all pending events.

pub fn connections(&self) -> &HashMap<u64, PooledConnection>

Returns a reference to the underlying connection map (read-only).

pub fn config(&self) -> &CpmPoolConfig

Returns the current configuration.