Trait Collect 

pub trait Collect:
    Clone
    + Send
    + Sync {
    // Provided methods
    fn connection_attempt(&self) { ... }
    fn connection_error(&self) { ... }
    fn connection_abort(&self) { ... }
    fn connection(&self) { ... }
    fn disconnect(&self) { ... }
    fn blacklist_add(&self) { ... }
    fn blacklist_remove(&self) { ... }
    fn request_queued(&self) { ... }
    fn request_forwarded(&self) { ... }
    fn pool_closed(&self) { ... }
}

An object implementing trait may collect metrics of a connection pool

Provided Methods

fn connection_attempt(&self)

We started establishing connection

This pairs either with connection on success or connection_abort and connection_error on error

fn connection_error(&self)

Error establishing connection

fn connection_abort(&self)

Aborted connection attempt (name changed, and doesn’t include address)

fn connection(&self)

Connection established successfully

fn disconnect(&self)

Connection closed (usully means name changed)

fn blacklist_add(&self)

Host address added to a blacklist (i.e. connection error)

fn blacklist_remove(&self)

Host address removed from a blacklist

Note this callback is only called when we’re searching for a new connection and all others are busy. I.e. unlisting a host from a blacklist may be delayed arbitrarily when not under backpressure. This may be fixed in future.

fn request_queued(&self)

Request queued in the internal queue

fn request_forwarded(&self)

Request unqueued from the internal queue and forwarded to a sink

Note: this might not mean that request is already sent as we can’t control the underlying sinks used.

fn pool_closed(&self)

Connection pool is closed

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Collect for Noop